Impact of the quality of coronal restoration versus the quality of root canal fillings on success of root canal treatment: a systematic review and meta-analysis

The impact of passive ultrasonic irrigation on the bond strength of two different self-etch adhesives to human pulp chamber dentine: a laboratory investigation

OBJECTIVES

To evaluate the impact of passive ultrasonic irrigation on the micro-tensile bond strength of two different self-etch adhesive systems, including a universal one-step adhesive and a two-step adhesive system, to pulp chamber dentine compared to conventional syringe irrigation.

METHODS

Twenty-four extracted human mandibular first molar teeth were chosen according to strict criteria and mounted in epoxy resin blocks. Subsequently, the pulp chambers were exposed using an Isomet cutting machine. The specimens were numbered and assigned to four groups (6 teeth each) based on the canal irrigation method and the adhesive system used as follows: Conventional syringe irrigation in which a universal one-step self-etch adhesive system was applied (CSIU), conventional syringe irrigation in which a two-step self-etch adhesive system was used (CSIT), passive ultrasonic irrigation in which a universal one-step self-etch adhesive system was utilized (PUIU), and passive ultrasonic irrigation in which a two-step self-etch adhesive system was employed (PUIT). Following placement of the final restoration and submission to simultaneous thermo-mechanical cycling (artificial aging) equivalent to 6-month intra-oral aging, the teeth were sectioned and dentine/restoration beams were prepared. The micro-tensile bond strength was evaluated and the failure mode was defined, with a confirmatory evaluation of the dentine-resin interface using a scanning electron microscope. Statistical analysis was conducted using one-way ANOVA and Tukey's post hoc tests to compare irrigation regimens for each adhesive technique independently, while failure modes of each adhesive system were represented as the frequency for each irrigation method. The significance level was set at 5%, with a confidence interval (CI) of 95%.

RESULTS

The micro-tensile bond strength of composite resin restorations to pulp chamber dentine was reduced significantly with ultrasonic irrigation with more unfavorable failure modes compared to syringe irrigation (P < 0.0001), irrespective of the type of adhesive system used. The means of the micro-tensile strength for teeth treated with the two-step adhesive system were 26.1055 ± 4.7611 MPa and 16.0079 ± 3.7665 MPa for CSIT and PUIT, respectively. For teeth treated with the universal adhesive system, the mean for CSIU (20.1818 ± 3.8500 MPa) was significantly higher than that of PUIU (11.2090 ± 2.9928 MPa). The micro-tensile bond strength was significantly greater with the two-step adhesive system compared to the universal adhesive, regardless of the irrigation method (p < 0.05). An adhesive layer with varying thickness was noted in all groups, displaying distinct morphological features.

CONCLUSIONS

Within the limitations of the present laboratory investigation, ultrasonic irrigation may negatively affect the bond between composite resin restorations and pulp chamber dentine compared to conventional syringe irrigation. The two-step self-etch adhesive tended to achieve a stronger bond to pulp chamber dentine than the universal one-step self-etch adhesive.

CLINICAL RELEVANCE

While ultrasonic irrigation would be essential for effective root canal debridement and disinfection, it is imperative for clinicians to consider its potential adverse effects. This method may considerably impact the bond strength of composite resin restorations to the pulp chamber dentine, particularly when compared to conventional syringe irrigation. In root canal-treated teeth, a two-step self-etch adhesive system might be more effective in maximizing the bond strength to pulp chamber dentine than a universal adhesive system. However, these findings were concluded under the conditions of the present study and must be interpreted cautiously. Further research is recommended to validate these results and fully understand the clinical ramifications of ultrasonic irrigation on adhesive performance in different dental situations.

CLINICAL TRIAL NUMBER

Non-applicable. Conducting the current experiment was limited to the approval of the local Research Ethics Committee at the Faculty of Dentistry, Minia University, Egypt (Committee No. 106, Registration No. 910, Date: April 30, 2024).

Success and failure of endodontic treatment: predictability, complications, challenges and maintenance

The fundamentals of successful endodontic treatment are an awareness of the aetiology of the disease process and an understanding of factors that affect outcome. This paper aims to outline the prognostic factors found in the endodontic outcome literature to facilitate options appraisal and predictable treatment delivery. We will discuss pre-treatment, treatment and post-treatment factors. In summary, the significance of infection control throughout treatment, provision of an adequate coronal seal and appropriate restoration of the root-filled tooth are highlighted.

Radiographic Assessment of the Quality of Post and Core Restorations and the Effect of the Gap Between the Post-Restoration and the Remaining Root Canal Filling on the Apical Status in a Saudi Subpopulation

Background

The objective of this study was to assess the quality of post and core restorations carried out by general dentists in the Hail region of Saudi Arabia using periapical radiographs. Additionally, the assessment included the examination of periapical lesions.

Methods

A comprehensive analysis was conducted on 301 periapical digital radiographs to assess various factors including the type of post, type of coronal restoration, post length in relation to crown and root length, presence of any abnormalities in the post space, condition of the remaining gutta-percha (GP), gap between the end of the post and the GP, and the presence of apical lesions. Analysis was conducted to determine the frequency distribution and cross-tabulation of the variables.

Results

Prefabricated metallic posts were most commonly used (62.1%), followed by metal posts which were found in 28.9% of the cases, and fiber posts which were used in 9.0% of the cases. The length of the posts in relation to the tooth were 2:1 in 32.6%, followed by 1:1 (27.9%) and 1:2 (23.6%). Parallel posts were used in 54.2% of cases, while the remaining 45.8% used tapered posts. Smooth posts were utilized in 77.1% of the cases, while serrated posts were utilized in 22.9%. Approximately 54.2% of the cases exhibited remaining GP of more than 5 mm, whereas 35.2% demonstrated adequate GP between 3-5 mm and 8.0% with remaining GP less than 3 mm. According to the study's findings, 65.1% of the samples under investigation had full coverage indirect restorations placed.

Conclusion

It was found that the post and core procedures' quality was comparable to earlier epidemiological studies. However, a significant proportion of posts were deemed to have poor technical quality, and apical periodontitis was seen in slightly more than one-third of the cases.

The effect of the gap between the cast post and residual gutta-percha and cement type on microleakage of endodontically treated teeth using the fluid filtration method

Background

The aim of this study was to investigate the impact of the distance between the gutta-percha and the post, as well as the type of cement used, on the incidence of microleakage in endodontically treated teeth.

Materials and Methods

This experimental-laboratory study involved 72 single-canal, single-rooted teeth, which were randomly sorted into six study groups and two control groups, each containing nine teeth. The six groups were further divided based on the distance between gutta-percha and post (0 mm, 0-2 mm, and >2 mm) and then categorized by cement type into glass ionomers and resins. Microleakage was evaluated using the fluid filtration method at 15 and 30 days. Data were analyzed using SPSS software, employing between-subjects effects and post hoc Tukey tests at a 5% significance level.

Results

Cement type did not significantly affect microleakage (P = 0.598). However, microleakage increased significantly with larger gaps between the post and remaining gutta-percha (P = 0.002). No significant difference in microleakage was observed between the gapless and ≤2 mm groups (P = 0.328). Similarly, ≤2 mm and >2 mm groups did not show any notable difference (P = 0.054). However, the difference in microleakage between the gapless group and the ≥2 mm gap group was significant (P = 0.001).

Conclusion

This study found no significant difference in microleakage between glass ionomers and resin cements. Only gaps >2 mm significantly affected microleakage.

Effect of using different materials and restorative techniques on cuspal deflection and microleakage in endodontically treated teeth

BACKGROUND

This study aimed to evaluate the effects of different restorative techniques and materials on cuspal deflection and microleakage in MOD restorations. Eight groups were tested using incremental and bulk-fill techniques, with or without fiber reinforcement. The restorative materials included Filtek Z250 and Filtek Bulk-fill Posterior, while reinforcement materials such as Interlig glass fiber, EverX Posterior, and Surefill SDR were incorporated to assess their impact.

METHODS

In total, 96 freshly extracted, sound human maxillary first premolars were selected and stored in 0.1% thymol solution at 37 °C. The teeth were randomly assigned into eight groups (n = 12). Standardized MOD cavities were prepared, followed by endodontic treatment and sealing with glass ionomer cement. The groups were as follows: Group 1-Filtek Z250 applied incrementally in 2-mm layers; Group 2-U-shaped Interlig glass fiber followed by incremental Filtek Z250; Group 3-Filtek Bulk-fill Posterior using the bulk technique; Group 4-U-shaped Interlig glass fiber followed by Filtek Bulk-fill Posterior; Group 5-EverX Posterior followed by incremental Filtek Z250; Group 6-EverX Posterior followed by Filtek Bulk-fill Posterior; Group 7-Surefill SDR followed by incremental Filtek Z250; and Group 8-Surefill SDR followed by Filtek Bulk-fill Posterior. Cuspal deflection was measured using a digital micrometer with 0.05 μm precision. Microleakage was assessed using a 0.5% basic fuchsin dye solution at 37 °C for 24 h, followed by sectioning and examination under magnification.

RESULTS

The lowest mean cuspal deflection was observed in Group 2 (15.8 μm), while the highest was in Group 5 (27.2 μm). Statistically significant differences were observed in cuspal deflection across the groups and over time (p < 0.05). Significant differences in microleakage scores were also found among the groups, indicating the impact of restorative materials and techniques on these outcomes (p < 0.05).

CONCLUSION

This study demonstrated that Filtek Z250 and Filtek Bulk-fill Posterior showed different effects on cuspal deflection and microleakage. The use of glass fiber and EverX Posterior improved restoration performance by reducing polymerization effects. Surefill SDR also reduced cuspal deflection due to its low polymerization shrinkage. Clinically, selecting the appropriate restorative materials and techniques based on the extent of tooth structure loss can improve long-term outcomes.

Comparison of fracture resistance between immediate and delayed composite restorations with or without fiber after root canal treatment: a field-emission-gun scanning electron microscope study

Background

This study aimed to evaluate the fracture resistance of immediate and delayed restorations after root canal treatment (RCT).

Methods

Sixty human intact premolar teeth were used. Teeth were prepared disto-occlusally. After RCT, teeth were randomly divided into two groups according to restoration times (immediate or 3 months delayed). The three month delay was imitated by thermomechanical aging. Then, samples were divided into six subgroups (n = 10). While I (Composite resin), II (Flowable bulk-fill) and III (Ribbond+Flowable bulk-fill) were restored immediately, Groups IV, V and VI were restored with temporary filling material and stored in distilled. After subjected to thermo-cycling (2,500 cycles, 5-55 °C) and exposed to 60,000 cycles in a chewing simulator, Group IV (Composite resin), V (Flowable bulk-fill) and VI (Ribbond+Flowable bulk-fill) were restored. All of the teeth were fractured on the universal testing machine. Failure modes were analyzed using scanning electron microscope. Data were analyzed using the Shapiro-Wilk and two-way ANOVA tests (p < 0.05).

Results

The highest fracture resistance was recorded in Group III while the lowest in Group VI. No statistically significant difference was observed among groups (p > 0.05). Most of the repairable fractures were seen in Groups I and II.

Conclusion

Delaying the permanent restorations of teeth for 3 months did not affect fracture resistance. However, it was suggested to avoid delaying restorations for obtaining repairable surfaces.

Effect of Er: YAG laser and different surface treatment methods on the push-out bond strength of glass fiber post to self adhesive resin cement

To compare the push-out bond strength of adhesive resin cement and glass fiber posts (GFP) at different root levels after exposure to Er: YAG laser irradiation compared to other conventional surface treatment procedures. A total of 24 mandibular premolars were decoronated, root canal treatment was done, post spaces were prepared, and roots were mounted in acrylic resin blocks. Fiber posts were divided into four groups (n = 6) according to surface treatment methods: (1) silane only (control group), (2) Er: YAG laser 1.5 W + silane, (3) 30% hydrogen peroxide + silane, (4) sandblasting with 50 μm aluminum oxide particles + silane. GFP were cemented using self-adhesive resin cement. Scanning electron microscope images with 500x magnification were taken for all groups. Push-out test was performed using a universal testing machine at different root levels. The difference between groups was statistically significant with laser group recording the highest mean ± SD value of push-out bond strength (5.668042 ± 1.16 MPa), followed by the H2O2 group, then the control group, meanwhile the lowest value was recorded with Sand-blasting group. There were no statistically significant differences between the Control group and Er: YAG group; Control group and sandblasted group. The difference between the radicular regions was not statistically significant, with the middle region recorded the highest push-out bond strength (4.746851 ± 0.73 MPa). GPF surface treatment using an Er: YAG laser is effective as it increases the retention to resin cement, while sandblasting decreases fiber post retention to resin cement. The hydrogen peroxide and the control groups give similar bond strength. The middle and apical regions of GFP have better retention to resin cement than the coronal one.

The effect of different bioceramic root canal sealer removal protocols on the bond strength of composite to coronal dentin in diabetic and non-diabetic patients: an ex vivo study

BACKGROUND

Diabetes mellitus can alter the physical and mechanical properties of dentin, compromising bonding. Furthermore, residual sealer on dentin may inhibit the bond strength. The aim of this study was to evaluate and compare the effects of different cleaning protocols on the adhesive bond strength of composite to coronal dentin contaminated with a tricalcium silicate (TCS)based root canal sealer in diabetic and non-diabetic patients.

METHODS

Diabetic (n = 50) and non-diabetic (n = 50) teeth were randomly divided into two groups. Coronal dentin surface specimens were obtained. The samples were contaminated with a TCS based sealer and then divided into five subgroups, four different cleaning procedures (dry cotton, wet cotton, ultrasonic-15, ultrasonic-30) and a control group (n = 10). The samples were restored with composite. A standard shear bond strength (SBS) test was performed. All failures were categorized as adhesive, cohesive or mixed. Data were analyzed using Independent Samples t-test and One-Way Analysis of Variance at a significance level of p < 0.05.

RESULTS

SBS values ​​were lower in diabetic dentin group than in non-diabetic dentin group. Dry cotton showed the lowest SBS value in both main groups. Ultrasonic-15 and ultrasonic-30 groups showed equal SBS values ​​in the non-diabetic group (p = 0.001), while the highest SBS was seen in the ultrasonic-30 subgroup in the diabetic dentin group. The highest adhesive failure was observed in the diabetic dentin group, and the dominant failure type was mixed for both groups.

CONCLUSION

The use of dry cotton was an insufficient method for removing bioceramic root canal sealer residues from coronal dentin in both the diabetic and non-diabetic patients. 15 s of ultrasonic activation was effective for removing bioceramic root canal sealer remnants from the non-diabetic coronal dentin. However, for the coronal dentin in the diabetic group, 30-sec ultrasonic activation was the most effective method for removing bioceramic root canal sealer remnants.

Fracture resistance and mode of failure of modified Polyether-ether-ketone versus lithium disilicate endocrowns

PURPOSE

The current study aimed to compare modified Polyether-ether-ketone's fracture resistance and failure mode versus lithium disilicate glass-ceramic endocrowns.

MATERIALS AND METHODS

A total of 16 butt-joint endocrown specimens on mandibular second molar teeth were fabricated and divided into two equivalent groups; Pressable modified Polyether-ether-ketone (PEEK) (BioHPP®) and Pressable lithium disilicate glass ceramic (IPS e.max® Press). A computer-aided design/computer-aided manufacturing system was used to digitally create and milled wax patterns. Final restorations were cemented each to its corresponding prepared tooth. Thermomechanical cycling loading representing one year of clinical service was done in a chewing simulator. Fracture resistance was evaluated utilizing a universal testing machine. The failure mode was evaluated by inspecting fractured surfaces using a Stereomicroscope and further examined by a Scanning Electron Microscope (SEM) amongst both groups.

RESULTS

A statistically significant variation in fracture resistance was recorded with a mean load of (2762.96 ± 216.15 N) for modified PEEK and (2175.91 ± 267.72 N) for lithium disilicate glass-ceramic endocrowns.

CONCLUSION

Modified PEEK endocrowns have higher fracture resistance than lithium disilicate glass-ceramic endocrowns. Moreover, the likeliness of catastrophic fracture in molars receiving endodontic treatment restored by modified PEEK is less than teeth restored with lithium disilicate glass ceramics.

Three-dimensional printed apical barrier model technology for pre-clinical dental education

BACKGROUND

Clinically, apical barrier procedure can be adopted to create an immediate artificial barrier for tooth with an open apex. Given that the quality of the barrier is crucial, the apical barrier procedure is known for its high technical sensitivity, posing significant learning challenges for dental students. Therefore, a new dental teaching model not only effectively enhances the future clinical skills of dental students but also benefits a wider range of patients.

OBJECTIVE

A new dental model for simulating apical barrier procedure in vitro, is helpful for dental students to practice apical barrier procedure. This study aims to design, assess, and evaluate the feasibility of a three-dimensional (3D) printed apical barrier model for pre-clinical dental education.

METHODS

A novel 3D-printed apical barrier model was developed, consisting of a tooth model and a matching blind box. Total 200 3D-printed apical barrier models were used to train dental students, and fifty fifth-year dental students participated in this voluntary hands-on course. Each student performed apical barrier procedures on four 3D-printed models. The outcome of the first model served as the representative result for the "direct barrier group", whereas the outcome of the fourth model represented the result of the "post-training barrier group". The quality of the apical barrier procedure was assessed through X-ray examination, and a questionnaire was used to evaluate the 3D-printed model's benefits, with scores ranging from 1 (strongly agree) to 5 (strongly disagree).

RESULTS

The overall rating for the 3D-printed model was 2.0 ± 0.6. The model was noted for its high degree of realism, ease of use, and practical applicability. Post-training assessments showed significant improvements in the density of apical barrier fillings (P< 0.05), reduction in underfilling rates (P< 0.05), and decrease in overfilling distances (P< 0.05). Students overwhelmingly agreed that the model was beneficial for training in apical barrier procedures (1.06 ± 0.24), helped identify their shortcomings (1.62 ± 0.53), and improved their operational skills (1.90 ± 0.51).

CONCLUSIONS

Both the questionnaire feedback and the quality of the fillings confirmed the feasibility and efficacy of the 3D-printed apical barrier model for dental education. The students had the possibility to learn the correct apical barrier procedure on printed dental models.

Effect of radiotherapy, immediate dentin sealing and irrigation simulating single- or two-visits endodontic treatment on the bond strength to pulp chamber dentin: an in vitro study

This study aimed to evaluate the influence of radiotherapy and different endodontic treatment protocols on the bond strength to pulp chamber dentin. Eighty mandibular molars were randomly divided into two groups (n = 40): non-irradiated and irradiated (60 Gy). The pulp chambers were sectioned, and each group was subdivided (n = 8), according to the endodontic treatment protocol: no treatment (Control); Single-visit; Two-visits; Immediate dentin sealing (IDS) + single-visit; and IDS + two-visits. Each endodontic treatment visit was simulated through irrigation with 2.5% NaOCl, 17% EDTA and distilled water. IDS was performed by actively applying two coats of a universal adhesive to the lateral walls of the pulp chamber. After, the pulp chambers were restored with resin composite and four sticks were obtained for microtensile test. In addition, the dentin of the pulp chamber roof was assessed for surface roughness, chemical composition, and topography after each treatment protocol. Two-way ANOVA, Tukey's post hoc, Mann-Whitney, Kruskal-Wallis and Dunn's post hoc were performed (α = 5%). The treatment protocol affected bond strength (p < 0.05), while the irradiation did not (p > 0.05). The control group presented the highest values (p < 0.05). The single-visit group demonstrated better performance compared to the other groups (p < 0.05), which did not differ from each other (p > 0.05) The use of IDS changed the surface roughness (p < 0.05), chemical composition (p < 0.05) and topography of the dentin. In conclusion, the treatment protocol influenced dentin adhesion, while irradiation did not.

Obturation quality of bioceramic sealers with different obturation techniques: a micro-CT evaluation

This micro-computed tomography (micro-CT) analysis in vitro study was designed to compare void volume in root canal fillings performed using the single-cone (SC) technique and the continuous wave condensation (CWC) technique with bioceramic (BC) sealer. Forty human-extracted, single-rooted mandibular premolars were cleaned, shaped, and divided into two groups (n = 20) based on the obturation technique. In the first group, obturation was performed using the CWC technique with TotalFill HiFlow BC sealer. In the second group, obturation was performed using the SC technique with the conventional TotalFill BC sealer. All roots were scanned with micro-CT, and ©CTAn software version 1.20.8.0 was used to measure the void volume of each root third in all samples. Despite the different obturation techniques, both groups exhibited voids in filled root canals. The overall mean void volume in the SC group (0.253 ± 0.186) was significantly higher (p = 0.000) than that in the CWC group (0.035 ± 0.043). The difference was significant in the coronal (p = 0.000) and middle (p = 0.017) thirds. The CWC technique with TotalFill HiFlow BC sealer achieved superior obturation quality compared to the SC technique with conventional BC sealer in oval-shaped premolars.

Unveiling the mechanical performance of partially replaced coronal restorations in root canal-treated teeth: an in-vitro study

OBJECTIVES

To compare the mechanical performance of partially replaced (repaired) intra-coronal restorations to totally replaced ones in root canal-treated teeth.

METHODS

Thirty maxillary second premolars were selected according to strict criteria, mounted on moulds, and had mesio-occluso-distal (MOD) cavities prepared. Resin composite restorative material was used to perform the initial restoration, followed by aging procedures using thermo-mechanical cycling fatigue to replicate six months of intraoral aging. The specimens were then randomly divided into two groups: a totally replaced restoration (TR) group (n = 15), which involved the preparation of a traditional endodontic access cavity after the complete removal of the pre-existing coronal filling; and a partially replaced restoration (PR) group (n = 15), which involved accessing the tooth through the pre-existing restoration without completely removing it. Root canal preparation and filling procedures were conducted, and the access cavity was sealed with a new resin composite restoration, followed by a new thermo-mechanical cycling aging procedure. Finally, the specimens were submitted to a static fracture test to measure specimen fracture strength and determine the failure mode pattern (repairable fracture or irreparable fracture). Chi-square and t-tests were used for statistical analysis.

RESULTS

Significant differences between the groups regarding their mechanical resistance were found. The average failure load of the TR group was 1115.13 N and 1330.23 N in the PR group (p = 0.002). Regarding the failure modes, the TR group exhibited eight irreparable fractures, while the PR group had four (p = 0.136).

CONCLUSIONS

Partially replaced restorations presented higher fracture strength and led to fewer irreparable fractures when compared to totally replaced restorations in root canal-treated teeth.

Evaluation of the Effect of Chitosan-Based Irrigation Solutions on the Bond Strength of Mineral Trioxide Aggregate to Bulk-Fill Composite

(1) Background: Bond strength between repair and restorative materials is crucial for endodontic success. This study assessed the effects of the following final irrigation solutions on the bond strength of mineral trioxide aggregate (MTA) to a bulk-fill composite: (1) 17% Ethylenediamine tetraacetic acid (EDTA); (2) 2% Chlorhexidine (CHX); (3) 0.2% chitosan; (4) 0.2% chitosan with 2% CHX; 5) 0.2% chitosan with AgNPs. (2) Methods: Sixty MTA samples were divided into six groups (n = 10) based on the final irrigation solution: 1. EDTA, 2. CHX, 3. Chitosan, 4. Chitosan-CHX, 5. Chitosan-AgNP, and 6. distilled water (control). After a 5-min solution exposure, each sample was restored with the bulk-fill composite, and the shear bond strength (SBS) was measured. Structural changes in MTA were analyzed using SEM and EDS, and failure modes were classified as adhesive, cohesive, or mixed. Data were analyzed by one-way ANOVA with Tamhane's T2 and Tukey's tests (α = 0.05). (3) Results: EDTA exhibited the lowest SBS (p < 0.001), while Chitosan-CHX showed the highest. SEM showed a spongy, void-rich surface in EDTA-treated MTA, with significant Ca depletion per EDS. Chitosan-CHX showed no structural change. Cohesive fractures within MTA were predominant. (4) Conclusions: EDTA significantly reduces SBS, while chitosan with CHX enhances bond strength.

Influence of Dentin Hybridization on the Chromatic Alteration of Teeth caused by Endodontic Sealers

This study evaluated the influence of dentin hybridization on coronary chromatic alteration of endodontically treated bovine teeth using different endodontic sealers and Portland cement. The 200 central incisors were endodontically treated using different materials (Sealapex, Bio-C Sealer, AH-Plus, Endofill, and Portland cement) and distributed according to the presence or absence of dentin hybridization. The teeth underwent colorimetric analysis using the Easyshade® spectrophotometer at four different times: determining the color of the dental substrate before root canal filling (RCF), 7 days, 60 days, and 180 days after RCF. The data were evaluated for normality and homogeneity by the Shapiro-Wilk and Levene tests. A two-way analysis of variance was performed, with Sidak's post-test for multiple comparisons. The significance level was 5%. Dentin hybridization influenced the coronary chromatic alteration of Sealapex® after 7 days and in Bio-C Sealer® and AH Plus® after 60 days. The AH Plus after 7 days obtained the highest ΔE* when hybridized, and the Endofill® obtained the highest ΔE* when not hybridized. The AH Plus after 60 days got the highest ΔE* when hybridized and non-hybridized. The Sealapex® after 180 days obtained the highest ΔE* when hybridized, and the AH Plus obtained the highest ΔE* when not hybridized. The studied root canal sealers behaved differently regarding coronary chromatic alteration, making it difficult to predict a particular behavior. All endodontic sealers caused clinically noticeable chromatic changes after 7 days, 60 days, and 180 days, regardless of hybridization.

Bonding Performance of a New Resin Core System with a Low-Polymerization-Shrinkage Monomer to Root Canal Dentin

Resin core build-ups following root canal treatment still have many issues. This study evaluated whether a new low-polymerization-shrinkage resin core system (LC2) could address these issues by assessing its bonding performance to root canal dentin using microtensile bond strength tests and gap formation using swept-source optical coherence tomography (SS-OCT). Twenty-four extracted human lower premolars were used for bonding performance tests, while forty-eight sound extracted human wisdom teeth were used for gap observation. Four systems were compared: Luminous Core LC flow (LC1), LC2, MI Core LC flow (MIC), and Filtek Fill & Core (FFC). Cylindrical cavities were prepared, bonded, and filled with resin cores, and gap formation was evaluated. The results showed significant differences in bond strength between the coronal and apical sides: LC1 (coronal: 29.9 ± 3.8 MPa; apical: 12.4 ± 2.0 MPa), LC2 (coronal: 31.2 ± 3.6 MPa; apical: 17.8 ± 3.6 MPa), MIC (coronal: 28.7 ± 3.8 MPa; apical: 8.8 ± 2.1 MPa), and FFC (coronal: 29.0 ± 4.2 MPa; apical: 9.5 ± 1.9 MPa). LC2 exhibited significantly higher bond strength at the apical side compared to the other systems (p < 0.05). Gap formation was significantly reduced in LC2 (10.9 ± 5.0%) and FFC (11.9 ± 5.0%) compared to LC1 (31.8 ± 10.5%) and MIC (32.0 ± 5.6%) (p < 0.05). These findings suggest that LC2 is advantageous for resin core build-ups, particularly in improving adhesion to root canal dentin and reducing gap formation.

Effect of different obturation techniques on treatment results in single-visit non-surgical endodontic retreatment: randomized controlled clinical study

BACKGROUND

Evaluating the effect of different obturation techniques on postoperative pain level and radiographic healing on non-surgical endodontic retreatment (NSER) applied in a single visit in teeth with a single root canal and apical periodontitis (AP).

MATERIALS AND METHODS

Sixty-three teeth from 50 systemically healthy patients (mean age 34.19 ± 9.75 years; 27 women, 23 men) were included in the study. Residual root canal filling materials were removed. All teeth were randomly divided into three groups according to the obturation technique: cold lateral compaction (CLC), continuous wave compaction (CWC), and thermoplasticized gutta-core (TGC). Pain status was evaluated using the Numerical Pain Rating Scale (NRS) in all cases. Periapical index (PAI) scores were recorded in preoperative and postoperative 6-month on the periapical radiographs. Data were analyzed as statistically (IBM, Armonk, NY, USA). The significance level was determined as p < 0.05.

RESULTS

It was found that more postoperative pain occurred in the 3rd-hour interval after CLC and CWC compared to the 7th-day interval (p < 0.05). There was no difference in postoperative pain between obturation techniques in all evaluated time intervals (p > 0.05). There was no difference in the PAI scores recorded at six months between obturation techniques for all periods (p > 0.05). Similar radiographic improvement was observed in all obturation techniques at 6-months (p > 0.05).

CONCLUSION

CLC, CWC, and TGC root canal obturation techniques were found to have similar efficacy after NSER in a single visit in teeth with AP at six months.

TRIAL REGISTRATION

The research was retrospectively registered on the website www.

CLINICALTRIALS

gov with the registration number NCT06226740 on 26/01/2024.

Teaching a New Obturation Technique in Preclinical Endodontic Training: Assessment of Student Learning Experience, Performance, and Self-Evaluation

INTRODUCTION

This study investigated the impact of implementing hydraulic condensation (HC) as a second obturation technique in the Endodontic Preclinical course for dental students trained in warm vertical compaction (WVC).

METHODS

A total of 70 students performed root canal treatment of 2 extracted molars; they performed the HC technique for the first time after a demonstration. The combination of the obturation technique (WVC or HC) and the type of molar (maxillary or mandibular) was randomly assigned, resulting in 4 groups (n = 35). The students answered a questionnaire appraising their learning experience and completed a self-evaluation rubric. Masked instructors graded projects. Data were statistically analyzed (significance set at 5%).

RESULTS

Most of the students (91%) considered learning 2 obturation techniques relevant and considered it difficult to perform the downpack in molars (P < .05). About half of the students (45.7%) responded that HC resulted in fewer errors and disagreed that WVC derives in a more homogeneous obturation; accordingly, 52.9% of the students selected the highest self-grading for HC obturations, while only 38.6% for WVC. No significant difference was found in the distribution of grades attributed by students and instructors (P > .05). Students reported significantly higher levels of confidence for HC and difficulty for WVC (P < .05). No difference was found between the techniques regarding the presence of voids. The presence of multiple errors was more frequent for WVC (P < .05).

CONCLUSION

The findings indicate a positive learning experience and comparable performance among preclinical dental students in implementing HC as an alternative obturation technique.

Contemporary Applications and Future Perspectives of Robots in Endodontics: A Scoping Review

BACKGROUND

In the era of modern advanced endodontics, the reduction of reliance on human hands and shifting towards robotics could benefit the precision and accuracy of endodontic treatment. This scoping review aims to describe current and emerging trends in the applications of robots in endodontics and highlight their limitations and future perspectives.

METHODS

This review followed the PRISMA Extension for Scoping Reviews (PRISMA-ScR) standards. A comprehensive search of internet databases was conducted until February 2024. Studies that specifically examined robots in the field of endodontics were included.

RESULTS

The studies focused on root canal cleaning, shaping, surgical procedures, and other applications. Robotic systems demonstrated improved accuracy, precision, reduced errors, and time savings compared with manual techniques.

CONCLUSION

Robotics in endodontics show promise, especially in surgical procedures, with AI integration enhancing accuracy and efficiency. Challenges such as cost, physical limitations, and absence of tactile feedback require further research and investment.

Assessment of Periodontitis Risk Factors in Endodontically Treated Teeth: A Cross-Sectional Study

The aim of the study was to collect data about the prevalence and risk factors of apical periodontitis in a population of endodontically treated patients. The study group included 151 patients (52 males, 99 females; mean age 48.36 ± 15.708 yrs.) with 391 endodontically treated teeth (mean follow-up of 5.25 ± 1.759 yrs.). According to the initial tooth diagnosis, root-filled teeth were divided into Group A, root-filled teeth treated for pulpitis or for the purpose of prosthetic pulpectomies (vital pulp group), and Group B, root-filled teeth with non-vital pulp (necrotic pulp). Clinical and radiographic evaluation of the root and its periapical area were performed to establish the success/failure of endodontic therapy, the quality of the root canal fillings (length, density, taper), and coronal restoration. The presence of recurrent caries, periodontal pathology, or endo-periodontal lesions were also recorded. Univariate and multivariate analyses were used to determine the risk factors for apical periodontitis and calculate their odds ratios (ORs). For the root-filled vital pulp tooth group, the highest risks for apical periodontitis are associated with inadequate homogeneity (OR 30.938), periodontitis (OR 9.226), and over-filling (OR 8.800). For the root-filled non-vital pulp tooth group, the highest risks are associated with periodontitis (OR 4.235) and age over 60 yrs. (OR 4.875). For the necrotic pulp tooth group, multivariate analysis identified an age > 60 yrs., filled molars, intracanal posts, poor coronal restoration quality, under-filling, and periodontitis as significant combined risk factors. Inadequate root canal filling and periodontitis in both groups were risk factors associated with most cases of apical periodontitis. Other risk factors include age > 60 yrs., poor coronal restoration quality, and the presence of intracanal posts in root-filled teeth with necrotic pulp.

Expert consensus on the diagnosis and therapy of endo-periodontal lesions

Endo-periodontal lesions (EPLs) involve both the periodontium and pulp tissue and have complicated etiologies and pathogenic mechanisms, including unique anatomical and microbiological characteristics and multiple contributing factors. This etiological complexity leads to difficulties in determining patient prognosis, posing great challenges in clinical practice. Furthermore, EPL-affected teeth require multidisciplinary therapy, including periodontal therapy, endodontic therapy and others, but there is still much debate about the appropriate timing of periodontal therapy and root canal therapy. By compiling the most recent findings on the etiology, pathogenesis, clinical characteristics, diagnosis, therapy, and prognosis of EPL-affected teeth, this consensus sought to support clinicians in making the best possible treatment decisions based on both biological and clinical evidence.

In vitro bacterial penetration and dissemination through dentinal tubules in roots filled with calcium silicate-based cements

The aim of this study was to assess whether calcium silicate root fillings prevent bacterial penetration and to determine how bacteria penetrate roots. Extracted single-rooted, single-canal human teeth were decoronated, prepared and filled with ProRootMTA or Biodentine (n = 12 each). Positive and negative (n = 2 each) controls were not filled. A two-chamber model was used with Streptococcus gordonii. The lower compartment was evaluated for turbidity over 150 days. Roots were split and examined for bacteria via SEM. The chi-squared test was used for comparisons (α = 0.05). Experimental groups had bacteria in their coronal thirds. Tubules contained bacteria in 90.9% and 91.7% of areas examined in the Biodentine and ProRootMTA groups, respectively, with no significant difference (p = 0.914). Experimental and negative roots had no turbidity with no significant difference between Biodentine and ProRootMTA (p = 1.000). Positive controls had turbidity. Bacteria penetrate roots via dentine tubules of root-filled teeth. Biodentine was comparable to ProRoot MTA.

Apical and lateral accuracy of intraradicular impressions made using the indirect and direct technique at three different locations: A comparative in vitro analysis

Background

There is limited literature available comparing the accuracy of intraradicular impressions made with a novel hybrid impression material using the indirect and direct technique at three different locations.

Materials and Methods

For this comparative in vitro analysis, postspace was prepared in 15 recently extracted teeth and impressions made with vinyl polysiloxane, polyether (PE), vinyl polyether silicone (VPES), and pattern resin. Postpatterns obtained were re-seated on the teeth and longitudinally sectioned. A binocular microscope was used to measure apical and lateral discrepancies at three locations (L1, L2, and L3). L1 at the postcore junction, L2 at the middle of the post space, and L3, 2 mm short of the apical end. The data obtained were statistically analyzed using the Statistical Package for the Social Sciences (SPSS) software. One-way analysis of variance (ANOVA) (intergroup) followed by Tukey's post hoc test with P ≤ 0.05 was used.

Results

The one-way ANOVA noted a highly significant difference at the apical location. Pattern resin had the highest apical discrepancy (151.93 ± 8.59 µm), whereas the lowest was with vinyl PE silicone (140.31 ± 11.46 µm). At L1, the highest discrepancy was seen with pattern resin (32.09 ± 2.31 µm), whereas the lowest was with the addition silicone (31.94 ± 2.54 µm). At L2, addition silicone (32.88 ± 2.81 µm) showed the highest discrepancy, whereas the lowest was with vinyl PE silicone (30.5 ± 8.79 µm). The PE group had the highest mean at the L3 location (31.38 ± 3.46 µm) and the lowest was with vinyl PE silicone (30.93 ± 2.25 µm). At all lateral locations, no significant difference was noted. Tukey's post hoc comparison showed a significant difference between pattern resin and VPES (11.62 µm) followed by pattern resin and addition silicone (11.47 µm) apically.

Conclusion

The indirect technique using VPES or addition silicone is more accurate than the direct technique at the apical location.

Does an incomplete ferrule affect the fracture of endodontically treated teeth? A systematic review of in vitro studies

OBJECTIVE

The purpose of this systematic review was to assess the impact of the incomplete ferrule on the fracture of endodontically treated teeth (ETT).

DATA

The keywords such as "incomplete ferrule," "ferrule," "ferrule effect," "residual dentin," "remaining dentin," or "remaining coronal dentin" were used for searching, and only in vitro studies investigating the incomplete ferrule effect on natural teeth were included.

SOURCES

PubMed, Medline, Embase, Cochrane Library, and Science Direct databases, and manual-searching.

STUDY SELECTION

The search strategy yielded 1633 hits, and a total of 19 in vitro studies closely related to the effect of incomplete ferrule on ETT were included.

CONCLUSION

The presence of an incomplete ferrule may significantly increase the fracture resistance of restored ETT, compared with restored ETT without ferrule. The number of residual axial walls of the incomplete ferrule may have an impact on the fracture resistance and fracture mode. The location of residual axial walls of the incomplete ferrule may affect the fracture resistance but not the fracture mode.

CLINICAL IMPLICATIONS

Limited data suggest that the presence of incomplete ferrule has a positive effect on the fracture resistance of restored ETT. An incomplete ferrule can be an alternative for restoring ETT when a complete ferrule is not present. Nevertheless, further high-quality studies are still needed to offer more robust evidence and to take potential confounding factors into account.

The use of sonic and ultrasonic activation of endodontic sealer to improve sealer filling quality in the root canal: a scoping review

This scoping review aimed to map whether the use of sonic and ultrasonic methods to activate the endodontic sealer improves the sealer filling quality in the root canal, considering the bond strength and intratubular penetration to the root dentin as evaluation criteria. The study protocol was prospectively registered and is available online ( https://osf.io/x5fma/ ). Reporting was based on PRISMA Extension for Scoping Reviews. The search was performed in Embase, PubMed, Scopus, and Web of Science. We selected studies without time and language restrictions that used sonic or ultrasonic methods to activate endodontic sealer, whose outcomes were bond strength and intratubular penetration. Three researchers independently selected the articles and collected data. Of 1422 articles, 19 were read in full and 13 studies were included. The vast majority of studies opted for direct activation of the endodontic sealer. The most investigated sealers were the epoxy resin-based sealers, and the ultrasonic activation method was the most explored. For the bond strength outcome, there was a trend toward higher values when the sealer was activated ultrasonically, but the findings seem to be divergent. The sonic activation was not effective for its intended purpose. For the outcome of intratubular penetration, the vast majority of studies indicate that the use of sonic and ultrasonic methods to activate the endodontic sealer is capable of increasing intratubular penetration. The use of sonic and ultrasonic methods to directly activate the endodontic sealer can increase the intratubular penetration of the sealer, but their benefits on the bond strength are uncertain.

Ill-fitting prosthesis is associated with an increased risk of elevated blood pressures

OBJECTIVE

Previous studies focused on the benefits of adequate prosthodontic treatment, while few studies have investigated the prosthodontic-related risks to health. As a modifiable oral health indicator, the association of ill-fitting prosthesis (IFP) with hypertension has not been fully explored.

METHODS

This cross-sectional study involved 158,659 adults in Beijing (2009-2017) receiving intra-oral examinations and blood pressure measurements. Logistic regression models were applied to assess the association of IFP with the prevalence of hypertension, systolic blood pressure (SBP) ≧ 140 mmHg and diastolic blood pressure (DBP) ≧ 90 mmHg, as well as subgroup analyses by different fixed IFP subgroups (according to involved teeth number) and removable IFP subgroup. We further investigated effect modifications among stratified populations.

RESULTS

158,659 individuals were included for analysis, 346 (26.86%) in IFP group and 27,380 (17.40%) in non-IFP group (p < 0.001) were hypertensive. After adjustment of sex, age, obesity, dyslipidaemia, diabetes, hsCRP, family history of CVD, self-reported smoking, self-reported drinking and WC, ORs of hypertension, SBP ≧ 140 mmHg and DBP ≧ 90 mmHg were 1.330 (95% CI: 1.162-1.522), 1.277 (95% CI: 1.098-1.486) and 1.376 (95% CI: 1.186-1.596), respectively (p < 0.05). Furthermore, after full adjustment, the number of involved teeth showed a significant incremental trend with hypertension risk in the population with and without IFP (p for trend <0.001). The IFP-blood pressure associations were more pronounced in females, 18-60 years, non-obese and diabetic participants.

CONCLUSION

As a modifiable oral indicator, IFP was significantly associated with a higher risk of hypertension.

Radiographic assessment of the quality of post and core restorations performed by general dental practitioners in Saudi Arabia

Background

Dentists utilize various techniques and materials for post and core restoration of endodontically treated teeth, which remains a noteworthy health concern and can be addressed through interdisciplinary strategies to enhance outcomes. Therefore, this study aimed to evaluate the technical quality of the residual gutta-percha (GP) and posts by analysing the periapical radiographs of endodontically restored teeth.

Methods

A total of 594 periapical digital radiographs were evaluated for tooth type, post material, post shape, design, diameter, length, residual GP, GP length, GP tapering, GP homogeneity, and final restoration. Frequency distribution and cross-tabulation of the variables were performed.

Results

Maxillary molars had the highest frequency of restorations, including posts, accounting for 27.4 %, followed by maxillary premolars (25.4 %) and maxillary anterior teeth (19.2 %). The prefabricated metallic posts were most commonly used (81.0 %), among these, 50.4 % were screwed posts. Tapered posts were the most commonly used (65.6 %). The percentage of posts with an acceptable length was 58.2 %. The most commonly used posts exhibited a width of one-third of the root diameter, accounting for 87.0 %. Suitable GP lengths were observed in 61.1 % of the restorations, and 62.8 % demonstrated adequate GP homogeneity. The findings of this study revealed that crown restoration accounted for 42.6 % of the studied sample.

Conclusions

The technical quality of the remaining GP after restoration was comparable to that of previous epidemiological investigations. However, the technical quality of the post was deemed suboptimal.

The efficacy of 3 root canal sealers combined with warm gutta-percha vertical compression technique in the treatment of dental pulp disease

To investigate the efficacy of 3 root canal sealants such as AH Plus, GuttaFlow and iRoot SP combined with warm gutta-percha vertical compression technique in the treatment of dental pulp disease. This was a single-center retrospective study. 180 patients with dental pulp disease were divided into AH Plus group (n = 60), GuttaFlow group (n = 60) and iRoot SP group (n = 60) according to the different treatment methods. Patients in different groups were treated with corresponding root canal sealant combined with warm gutta-percha vertical compression technique. The quality of root canal filling, filling time, filling area ratio, the incidence of pain after operation, serum interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) and efficacy at 6 months after operation were compared among the 3 groups, respectively. The filling time in the GuttaFlow group and the iRoot SP group was significantly shorter than that in the AH Plus group (P < .001). There were significant differences in pain grade (P = .015) and pain rate (P = .016) among the 3 groups, and the pain rate in the GuttaFlow group and the iRoot SP group was significantly lower than that in the AH Plus group (P = .016). The time-point effect, intergroup effect and time-groups effect of serum TNF-α and IL-6 were significantly different (P < .001), and the levels of the 3 groups after treatment were significantly lower than those before treatment (P < .05), and the levels were significantly lower in the GuttaFlow group and the iRoot SP group (P < .05). There were significant differences in efficacy grading and effective rate among the 3 groups (P = .028), and the effective rate of iRoot SP group was significantly higher than that of AH Plus group (P < .05). The iRoot SP or GuttaFlow as root canal sealant combined with warm gutta-percha vertical compression technique in the treatment of dental pulp disease is better than AH Plus, and the former one can shorten the filling time, relieve the postoperative pain and improve the inflammatory response, but the long-term apical sealing effect of iRoot SP is better than GuttaFlow.

Evaluation of calcium hydroxide root canal filling materials by cone beam computed tomography and three-dimensional modeling

AIM

The aim of this study was to compare the effectiveness of filling pastes in resin prototype primary molars by cone beam computed tomography (CBCT) and 3D modeling.

Effect of final irrigation protocols with chitosan nanoparticle and genipin on dentine against collagenase degradation: An ex-vivo study

AIM

Endodontic irrigants may affect the mechanical and chemical properties of dentine. This study evaluated the effects of various final irrigation protocols including the use of chitosan nanoparticle (CSnp) and cross-linking with genipin on the (1) mechanical and (2) chemical properties of dentine against enzymatic degradation.

METHODOLOGY

CSnp was synthesized and characterized considering physiochemical parameters and stability. The root canals of 90 single-rooted teeth were prepared and irrigated with NaOCl. Dentine discs were obtained and divided into groups according to the following irrigation protocols: Group NaOCl+EDTA, Group NaOCl+CSnp, Group NaOCl+EDTA+CSnp, Group NaOCl+CSnp+Genipin, Group NaOCl+EDTA+CSnp+Genipin and Group distilled water. (1) Mechanical changes were determined by microhardness analysis using Vickers-tester. (2) Chemical changes were determined by evaluating molecular and elemental compositions of dentine using Fourier transform infrared spectroscopy (FTIR) analysis and scanning electron microscope (SEM)/energy dispersive X-ray spectroscopy (EDS) analysis, respectively. All analyses were repeated after the discs were kept in collagenase for 24 h. Data were analysed with repeated measures analysis of variance and Bonferroni correction for microhardness analysis, and Kruskal-Wallis and Wilcoxon tests for FTIR and SEM/EDS analyses (p = .05).

RESULTS

(1) Collagenase application did not have a negative effect on microhardness only in Group NaOCl+EDTA+CSnp+Genipin when compared with the post-irrigation values (p > .05). Post-collagenase microhardness of Group NaOCl+EDTA+CSnp and Group NaOCl+CSnp+Genipin was similar to the initial microhardness (p > .05). (2) After collagenase, Amide III/PO 4 3 - ratio presented no change in Group NaOCl+EDTA+CSnp, Group NaOCl+CSnp+Genipin and Group NaOCl+EDTA+CSnp+Genipin (p > .05), while decreased in other groups (p < .05). Collagenase did not affectCO 3 2 - /PO 4 3 - ratio in the groups (p > .05). There were no changes in the groups in terms of elemental level before and after collagenase application (p > .05).

CONCLUSIONS

CSnp and genipin positively affected the microhardness and molecular composition of dentine. This effect was more pronounced when CSnp was used after EDTA.

Effects of endodontic irrigation solutions on structural, chemical, and mechanical properties of coronal dentin: A scoping review

OBJECTIVE

This review aims to assess structural, chemical, and mechanical properties of coronal dentin after endodontic irrigation.

MATERIALS AND METHODS

Reporting followed the PRISMA extension for scoping reviews. An electronic search was carried out in PubMed, Embase, and Cochrane Library. Records filtered by language and published up to November 4, 2022 were independently screened by two researchers. Studies evaluating structural, chemical, or mechanical properties of human permanent coronal dentin after irrigation within the scope of nonsurgical root canal treatment were included. Data were extracted regarding study type, sample description and size, experimental groups, outcome, evaluation method, and main findings.

RESULTS

From the initial 1916 studies, and by adding 2 cross-references, 11 in vitro studies were included. Seven studies provide ultrastructural and/or chemical characterization, and six assessed microhardness and/or flexural strength. One percent to 8% sodium hypochlorite (NaOCl) and 1%-17% ethylenediaminetetraacetic acid (EDTA) were the most commonly tested solutions, with contact times of 2-240 min (NaOCl) and 1-1440 min (EDTA) being evaluated.

CONCLUSIONS

Overall, the literature is consensual regarding the inevitable impact of NaOCl and chelating agents on coronal dentin, with both deproteinizing and decalcifying effects being concentration- and time-dependent. The alteration of mechanical parameters further confirmed the surface and subsurface ultrastructural and chemical changes.

CLINICAL SIGNIFICANCE

Endodontic treatment success highly depends on restorative sealing. Understanding the result of exposing coronal dentin, the main substrate for bonding, to irrigants' action is crucial. The deproteinizing and decalcifying effects of NaOCl and chelating agents are both concentration- and time-dependent, causing surface and subsurface ultrastructural, chemical, and mechanical alterations.

Reprint of: The Effect of Mineral Trioxide Aggregate Obturation Levels on the Outcome of Endodontic Retreatment: An Observational Study

INTRODUCTION

No clinical studies have examined the effect of mineral trioxide aggregate (MTA) obturation levels on the outcome of endodontic retreatment. This retrospective study examined treatment outcomes in three cohorts that compared overfilling, flush filling, and underfilling after orthograde retreatment using MTA.

METHODS

Two hundred fifty patients with 264 teeth diagnosed with previously treated root canals and apical periodontitis retreated in a private endodontic practice were included. All teeth received MTA obturation and the extent of the final filling level was measured in relation to the major apical foramen. After 6-month follow-ups, all nonhealing cases were treated surgically. After 24- to 72-month reviews, the effect of preoperative lesion size and the degree of MTA obturation level were assessed. Multiple linear regression and time-to-event analysis using Stata 17 software (StataCorp LLC, College Station, TX) were used to evaluate the data.

RESULTS

Within the three cohorts, 99 out of 108 overfilled teeth (91.7%), 90 out of 103 flush fills (87.4%), and 10 out of 53 underfilled teeth (18.9%) healed and were successfully retreated without surgery at 48-months. When surgical outcomes were included, the combined healed proportion was 93.2%. Preoperative lesion size was found to be an important predictor for retreatment nonhealing. A 1-mm increase in lesion size at baseline resulted in an estimated 11% (95% CI 1.04, 1.18)-38% (95% CI 1.22, 1.58) increase in the risk of surgery. Compared to overfilling and flush filling, underfilling was associated with an approximately three-fold increase in requiring surgery and characterized by delayed healing.

CONCLUSION

MTA obturation is a viable retreatment option for teeth with nonhealing endodontic treatment. MTA overfills or flush fillings do not adversely affect healing outcomes. However, MTA underfilling increases the chances for nonhealing and surgical intervention.

Predictors of apical periodontitis in root canal treated teeth from an adult Nepalese subpopulation: a cross-sectional study

BACKGROUND

Endodontic literature search revealed that no study has been conducted to evaluate the prevalence of apical periodontitis (AP) in root canal treated teeth from an adult Nepalese population of Madhesh Province. Consequently, little is known about the extent and risk factors associated with it. This study aimed to determine AP prevalence in root canal treated teeth from an adult Nepalese subpopulation and to analyze the related risk factors including age, sex, tooth type, type of coronal restoration and quality of root canal treatment and coronal restoration as predictors of AP.

METHODS

Digital panoramic radiographs were evaluated. Periapical status of 300 root canal-treated teeth was scored by using the periapical index. The quality of root canal treatment and coronal restorations were categorized as adequate or inadequate through radiographic and clinical evaluation. The data were analyzed using univariate and multivariate logistic regression models.

RESULTS

Prevalence of AP in the present study was 31.7%. In 45.7% of the treated teeth, quality of root canal treatment was adequate whereas 46% of the cases had adequate coronal restorations. Multivariate logistic regression analysis revealed statistically significant associations and remarkably increased risk for AP in teeth with inadequate root canal treatment (odds ratio [OR] = 7.92; 95% CI: 3.96-15.82; p < 0.001) whereas lower risk for AP was found in females (OR = 0.51; 95% CI: 0.28-0.90; p = 0.021) and in teeth restored with crown (OR = 0.22; 95% CI: 0.09-0.51; p < 0.001) and filling (OR = 0.18; 95% CI: 0.08-0.42; p < 0.001). Quality of coronal restoration, tooth type and age of the patient were not found to be the predictors of AP.

CONCLUSIONS

Within the limits of this study, a high prevalence of AP and poor overall quality of root canal treatment and coronal restoration was found in the subpopulation studied. Quality of root canal treatment, type of coronal restoration and sex of the patient are significant predictors of possible AP development in root canal treated teeth. Substantial efforts are needed to improve the endodontic treatment standards.

Effect of sodium hypochlorite, ethylenediaminetetraacetic acid, and dual-rinse irrigation on dentin adhesion using an etch-and-rinse or self-etch approach

The aim was to investigate the influence of endodontic irrigation solutions and protocols on the micro-tensile bond strength (μTBS) to dentin using an etch-and-rinse (ER) or self-etch (SE) adhesive approach. Eighty extracted human molars were ground to dentin. After pretreating for 27 min (21 min-3 min-3 min) with five different endodontic irrigation protocols (Group 1: NaOCl-EDTA-NaOCl; Group 2: NaOCl-NaOCl-EDTA; Group 3: NaOCl-NaCl-NaOCl; Group 4: Dual Rinse-Dual Rinse-Dual Rinse; Group 5: NaCl-NaCl-NaCl), an ER (Optibond FL, Kerr) or a SE (Clearfil SE Bond, Kuraray) adhesive system was applied. After light-curing, composite build-ups were made and cut into dentin-composite sticks. μTBS and failure modes were analyzed. Nonparametric statistical analyses (α = 0.05) were performed for comparison of the five groups within each type of adhesive as well as between the two adhesive systems used. The use of an ER instead of a SE adhesive system resulted in significantly higher μTBS for all irrigation protocols except for group 1 (NaOCl-EDTA-NaOCl) and 2 (NaOCl-NaOCl-EDTA). A statistical difference between the five different endodontic irrigation protocols was only found within the SE adhesive group, where group 1 (NaOCl-EDTA-NaOCl) achieved highest values. The use of an ER adhesive system cancels out the effect of the endodontic irrigation solution. The highest μTBS was achieved when using a NaOCl-EDTA-NaOCl-irrigation protocol in combination with Clearfil SE Bond, which shows that the selection of the endodontic irrigation should match the corresponding SE adhesive system.

Predicting early endodontic treatment failure following primary root canal treatment

BACKGROUND

Understanding when and why endodontic treatments fail could help clinicians make prognoses and thus improve treatment outcomes. This study was aimed to assess potential predictors of early endodontic treatment failure. We explored factors contributing to the failure of initial root canal treatment were explored, with a specific emphasis on evaluating the influence of the time elapsed since the initial treatment.

METHODS

This retrospective cohort study enrolled 1262 patients who sought endodontic treatment at our department and 175 patients were included for analysis. Potential causes of endodontic treatment failure were investigated, such as inadequate obturation quality, inadequate coronal status, the presence of additional untreated canals, anatomical complexity, instrument separation, iatrogenic perforation, cracks, and endodontic-periodontal lesions. The patients were divided into "short-term" and "long-term" groups depending on the time that had passed since the initial treatment (i.e., < 5 and > 10 years, respectively). The causes of failure in the short-term and long-term group were analyzed and compared using logistic regression analyses. Subgroup analysis was performed according to the number of years since the initial treatment in the short-term group to further investigate the association between the time and cause of failure (i.e., < 1, 2, 3, and 4 years, respectively).

RESULTS

Untreated additional canals were present in 21.7% of all cases, and in 36.9 and 6.4% of cases in the short-term and long-term groups, respectively. Multivariable analysis showed that the presence of untreated additional canals was significantly associated with short-term compared to long-term failure. Untreated additional canals were also associated with endodontic failure within 1, 2, 3, and 4 years.

CONCLUSIONS

The presence of untreated additional canals was a predictor of endodontic failure within 5 years following initial root canal treatment. To optimize long-term prognosis, it is important to detect and treat all root canals during the initial treatment.

The Outcomes of Endodontically Treated Teeth Restored with Custom-Made Cast Post-and-Core Restorations: A Retrospective Cohort Study

INTRODUCTION

Custom-made cast post-and-core (CMCPC) restorations have long been used to restore structurally deficient endodontically treated teeth (ETT). However, the evidence regarding their impact on the outcomes of ETT is largely inconclusive. This study evaluated the long-term treatment outcome of ETT restored with CMCPC.

METHODS

This retrospective cohort study examined the dental records of patients that received CMCPC at a specialty private practice in Toronto, Canada between 1999 and 2021. The proportion of ETT with complete periapical healing and those that survived were estimated, and prognostic factors were investigated using multiple logistic and Cox regression analyses respectively (P < .05).

RESULTS

A total of 500 and 1000 teeth met periapical healing and survival criteria, respectively. The periapical healing rate was 88.8% and was associated with the presence of baseline periapical radiolucency [odds ratio = 0.1; 95% confidence interval (CI), 0.05-0.2; P < .001]. The survival after a median follow-up time of 52.9 months (interquartile range: 26.5-99.4) was 90.1% and was associated with <75% of root length in bone [hazard ratio (HR) = 2.6; 95% CI, 1.0-6.6; P = .033], type and quality of final restoration (HR = 2.09; 95% CI, 1.1-3.9; P = .020; HR = 2.3; 95% CI, 1.2-4.5; P = .008, respectively), and the presence of periapical radiolucency at the latest recall (HR = 3.2; 95% CI, 1.7-6.3; P < .001).

CONCLUSIONS

The outcome of ETT restored with CMCPC was favorable. CMCPC may be regarded as a viable restorative option for structurally deficient ETT.

The association of endodontic prognostic factors with the presence of periapical lesion, its volume, and bone characteristics in endodontically treated molars: a cross-sectional study

BACKGROUND

This study intended to evaluate the association between several endodontic prognostic factors with the presence of periapical lesions (PLs), their volume, and bone characteristics including cortical bone destruction (CBD) and buccal plate bone height (BPBH) in root-filled molar teeth using cone-beam computed tomography.

METHODS

A collection of 143 scans of endodontically treated maxillary/mandibular first or second molars recorded over 8 years, were obtained from a specialized radiology center. Data on prognostic factors including tooth number, gender, jaw type, the status and number of missed canals, obturation length, restoration type, presence of a separated instrument, presence of a post or screw in the canals, and presence of perforation were collected. The assessed outcomes included PL presence, PL volume, CBD, and BPBH. The association between prognostic factors and outcomes was evaluated using multiple logistic regression models with adjusted covariates and multifactorial ANOVA at a significance level of 0.05.

RESULTS

A total of 282 molars from 82 women and 50 men with a mean age of 40.6 ± 12.27 were included. Among those, 139 teeth presented PL with a mean volume of 18.68 mm3. CBD was prevalent in 137 teeth and the mean BPBH appeared to be 9.45 mm. The presence of a missed canal (OR = 10.022, P < .05), underfilled canal (OR = 3.725, P < .05), overfilled canal (OR = 15.859, P = .018), and perforation (OR = 15.261, P = .013) was significantly associated with PLs. None of the prognostic factors could considerably contribute to the CBD (P > .05). The presence of a missed canal was positively associated with the PL volume (P < .05). Similarly, missed canals (P < .05), perforation (P < .05), and separated instruments (P = .004) were associated with a significantly reduced BPBH.

CONCLUSIONS

Overfillings, perforations, missed canals, and underfillings were identified as remarkable predictors of PL, arranged in descending order of their respective impact. The only factor capable of significantly increasing the PL volume was the missed canal. In brief, obturation length errors, perforations, missed canals, and separated instruments were robustly correlated with endodontic failure, which highlights the importance of mitigating the potential for errors by following the fundamentals of endodontics.

Effect of Obturation Techniques on the Quality of Root Canal Fillings: A Systematic Review and Meta-analysis of in Vitro Studies

Introduction

The current study aimed to compare the quality of root canal obturation performed with cold lateral condensation with other obturation techniques.

Materials and Methods

Diverse Search was conducted using six electronic/academic databases following PICOS (i.e. population, intervention, control, outcomes, and study design) strategy: (P) Extracted mature permanent teeth; (I) Obturation techniques except for cold lateral condensation; (C) Cold lateral condensation tyechnique; (O) Quality of root canal obturation; and (S) In vitro studies assessing parameters using micro-computed tomography. The statistical method used for the meta-analyses was the "inverse variance DerSimonian-Laird test". The heterogeneity data was calculated using the T2, Cochran Q test, and I2 statistics.

Results

Fifteen studies were included for the final analysis; one had a low risk of bias, eight a moderate risk, and six a high risk of bias. Ten studies were selected for meta-analyses; three studies comparing cold lateral condensation with carrier-based gutta-percha techniques [P=0.96; mean difference (MD)=-0.02; confidence interval (CI): (-0.77, 0.73); I2=21%]; three comparing cold lateral condensation with single-cone techniques [P=0.75; MD=-0.39; CI: (-2.77, 1.99); I2=92%]; two comparing cold lateral condensation and thermo-plasticized injectable techniques [P=0.37; MD=5.91; CI: (-7.13,18.94); I2=99%]; and five comparing cold lateral condensation with warm vertical condensation techniques [P<0.0001; MD=5.29; CI=(2.84, 7.74); I2=92%]. The overall effect reported significant results [P=0.0003; MD=2.69; CI=(1.23, 4.16); I2=96%]; favoring fewer voids and gaps for the other used obturation techniques.

Conclusions

Cold lateral condensation and single-cone techniques presented no statistical differences. Nonetheless, Warm vertical condensation technique had better results compared to cold lateral condensation.

Assessment of isthmus filling using two obturation techniques performed by students with different levels of clinical experience

Background/purpose

Root canal filling is a necessary skill for dental students and an important aspect of endodontic education. This study aimed to evaluate the effect of students' clinical experiences on isthmus filling using different techniques and sealers.

Materials and methods

One hundred eight three-dimensional-printed resin replicas of isthmus were divided into six groups and either continuous wave of condensation (CWC) or single-cone obturation (SC) was performed. One of three sealers (AH Plus Jet®, GuttaFlow2, iRoot SP) was used together with a size-fitted gutta-percha master cone. All the obturations were completed by students with three different levels of clinical experience including senior postgraduate students (SPS), junior postgraduate students (JPS), and undergraduate students (US). The percentages of filled areas (PFA) at 2, 4, 6, and 8 mm from the apex were analyzed using a light microscope. Data were analyzed using the Mann-Whitney U test or Kruskal-Wallis 1-way ANOVA with Dunn's tests (α = 0.05).

Results

The CWC group exhibited a higher PFA than the SC group (P < 0.05). The PFA was higher in the SPS group than in the JPS group or the US group with CWC (P < 0.05). The three clinical experience groups showed similar PFAs with SC (P > 0.05); however, when using SC with iRoot SP, the PFA was higher than with either of the other two sealers (P < 0.05).

Conclusion

CWC was found to be technique-sensitive and required clinical training. With SC, clinical experience did not improve the quality of isthmus filling without additional training. CWC was superior to SC for type IV isthmuses. When using SC, better filling quality was obtained with a bioceramic sealer.

A laboratory investigation on the effect of biguanide- and pyridine-derived antiseptics on the adhesion of resin composites to dentin

Optimal bonding of adhesive restorations to dentin is crucial to prevent microleakage and enhance the survival of root-filled teeth. The aim of this study was to investigate the effect of chlorhexidine (CHX), alexidine (ALX) and octenidine dihydrochloride (OCT) on the bond strength of resin composites to coronal dentin. Human coronal dentin specimens were treated with 2% CHX, 0.1% ALX, 0.1% OCT or saline then restored with traditional or bulk-fill resin composites. The adhesion strength between the resin and dentin was measured using the microtensile bond strength and failure mode was determined using a stereomicroscope. Treatment with ALX and OCT resulted in significantly greater μTBS compared with CHX and saline, irrespective of the resin composite used. Alexidine treatment predominantly resulted in mixed failure, while adhesive failures were frequently observed in CHX and saline-treated dentin. In conclusion, final irrigation with ALX or OCT improved the bonding of resin composites to dentin.

Diabetes Mellitus Increases the Risk of Apical Periodontitis in Endodontically-Treated Teeth: A Meta-Analysis from 15 Studies

INTRODUCTION

At present, the incidence of diabetes mellitus (DM) is gradually increasing globally. In clinical practice, many patients with diabetes with apical periodontitis (AP) have poor and slow healing of periapical lesions. However, the potential relationship between the 2 is still unclear and controversial. The consensus is that DM can be deemed a risk factor for AP in endodontically-treated teeth. Therefore, we pooled existing studies and carried out a meta-analysis to explore the potential association between the 2.

METHODS

Studies that met the inclusion criteria were selected from the database, and relevant data were extracted. Stata SE 17.0 software was used to analyze the relevant data, and the Newcastle-Ottawa Scale was used to assess the literature's quality. The pooled odds ratio (OR) with a 95% confidence interval (CI) was used to determine the strength of the association between DM and the prevalence of AP after root canal treatment (RCT).

RESULTS

After searching, 262 relevant studies were retrieved, fifteen of which met the inclusion criteria. A total of 1087 patients with 2226 teeth were included in this meta-analysis. According to the findings, diabetics showed a higher prevalence of AP after RCT than controls at the tooth level (OR = 1.51, 95% CI = 1.22-1.87, P < .01). At the patient level, DM increased the probability of developing AP in RCT teeth more than 3 times (OR = 3.38, 95% CI = 1.65-6.93, P < .01). Additionally, subgroup analysis was performed by blood glucose status, preoperative AP, and study design. Except for the status of blood glucose, the results were significant in the other 2 groups (P < .05).

CONCLUSIONS

Available scientific evidence suggests that DM may increase the risk of AP in endodontically-treated teeth. In teeth with preoperative AP, DM might promote the development of AP.

Differential expression of circular RNAs in interleukin 6-promoted osteogenic differentiation of human stem cells from apical papilla

INTRODUCTION

Studies have shown that interleukin 6 (IL-6) can regulate stem cell osteogenic differentiation; however, the exact mechanism is not clear. Circular RNAs (circRNAs) are closed circular non-coding RNAs that are involved in the process of stem cell osteogenic differentiation. Therefore, the purpose of this present study was to investigate the effect of IL-6 treatment on osteogenic differentiation of human apical tooth papillae stem cells (hSCAPs), and to detect the difference in circRNA expression using gene microarray technology.

METHODS

After extraction and identification of hSCAPs, alkaline phosphatase (ALP) activity, alizarin red staining, and calcium ion quantitative assay were used to determine the changes of ALP enzyme, mineralized nodules, and matrix calcium levels before and after IL-6 treatment of hSCAPs gene microarray technology was used to analyze the changes in circRNA expression levels before and after IL-6 induction of mineralization. The four selected circRNAs were validated by qRT-PCR. Moreover, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to predict the potential functions and biological signaling pathways of circRNAs. Finally, these data are integrated and analyzed to construct circRNA-microRNA-mRNA networks.

RESULTS

Alp and Alizarin red staining confirmed that IL-6 promoted the osteogenic differentiation of hSCAPs. The gene microarray results identified 132 differentially expressed circRNAs, of which 117 were upregulated and 15 were downregulated. Bioinformatic analysis predicted that the circRNA-406620/miR-103a-3p/FAT atypical cadherin 4 (FAT4) pathway might be involved in regulating IL-6 to promote osteogenic differentiation of hSCAPs.

CONCLUSION

Differentially expressed circRNAs might be closely involved in regulating IL-6 to promote osteogenic differentiation of hSCAPs.

Functionalization of gutta-percha surfaces with argon and oxygen plasma treatments to enhance adhesiveness

Gutta-percha's lack of adhesion has been presented as a drawback to avoid gaps at sealer/gutta-percha interface. Plasma treatments have been scarcely assessed on gutta-percha surfaces as a method of enhancing adhesiveness. This study aimed to evaluate the effect of low-pressure Argon and Oxygen plasma atmospheres on conventional and bioceramic gutta-percha standardized smooth discs, assessing their roughness, surface free energy, chemical structure, and sealer wettability. A Low-Pressure Plasma Cleaner by Diener Electronic (Zepto Model) was used. Different gases (Argon or Oxygen), powers (25 W, or 50 W), and exposure times (30 s, 60 s, 120 s, or 180 s) were tested in control and experimental groups. Kruskal-Wallis and Student's t-test were used in data analysis. Statistically significant differences were detected when P < 0.05. Both gases showed different behaviors according to the parameters selected. Even though chemical changes were detected, the basic molecular structure was maintained. Argon or Oxygen plasma treatments favoured the wetting of conventional and bioceramic gutta-perchas by Endoresin and AH Plus Bioceramic sealers (P < 0.001). Overall, the functionalization of gutta-percha surfaces with Argon or Oxygen plasma treatments can increase roughness, surface free energy and wettability, which might improve its adhesive properties when compared to non-treated gutta-percha.

Particulate Filler and Discontinuous Fiber Filler Resin Composite's Adaptation and Bonding to Intra-Radicular Dentin

The aim of this study was to assess adaptation and bonding to root canal dentin of discontinuous (short) glass fiber-reinforced composite to intra-radicular dentin (DSGFRC).

METHODS

Seventy virgin human teeth were extracted and then endodontically treated; then samples were randomly divided into 7 groups (n = 10), based on the materials' combinations as follows: Group 1, a two-bottle universal adhesive + DSGFRC; Group 2, a single-component universal adhesive + DSGFRC; Groups 3 and 4, the same materials of Goups 1 and 2 were used but after cleaning of the canal walls with 17% EDTA and final irrigation with 5.25% NaOCl Ultrasound Activated (UA); Group 5, traditional prefabricated fiber posts were luted after being silanized with G-Multi Primer; Groups 6 and 7, like Group 5 but after ultrasonic irrigation (UA). All sample roots were cut 1 mm thick (n = 10) to be evaluated regarding root canal adaptation using a light microscope and scanning electron microscope (SEM) and push-out bond strength. These results were statistically analyzed by Kruskal-Wallis analysis of variance by ranks. The level of significance was set at p < 0.05.

RESULTS

Bond strength forces varied between 6.66 and 8.37 MPa and no statistically significant differences were recorded among the groups. By microscopic examination, it was noted that ultrasonic irrigation increased the adaptation of the materials to the dentin surface.

CONCLUSIONS

Within the limitations of this in vitro study, it may be concluded that when DSGFRC was used for intracanal anchorage in the post-endodontic reconstruction, similar push-out retentive force and strength to those of traditional fiber posts cemented with particulate filler resin composite cements were achieved.

Phosphoric acid treatment enhances adaptation of glass-ionomer cement to bioceramic sealer-conditioned dentin

Background

This study evaluated the interface between fresh eugenol/bioceramic sealer-conditioned coronal dentin and high-viscous glass-ionomer cement (HVGIC), treated with various dentin conditioners (saline, 10% polyacrylic acid, and 37% phosphoric acid).

Materials and Methods

Standard endodontic access preparation and instrumentation were done in 21 freshly extracted mandibular molar teeth in this in vitro study. Teeth were divided into two interventional groups (n = 9/group), based on the type of sealer (zinc oxide eugenol [ZOE]/bioceramic [BioRoot RCS] sealer) used for obturation. Samples were further subdivided based on the type of dentin-conditioning procedures performed (saline/10% polyacrylic acid/37% phosphoric acid). Post dentin conditioning, the access cavity was sealed with HVGIC. Later, material-dentin interfacial analysis and elemental analysis were done using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy.

Results

The interfacial SEM images of HVGIC layered over B-RCS/ZOE sealer-conditioned dentin, treated with saline, showed predominantly adhesive debonding failures, whereas cohesive debonding was observed with polyacrylic and phosphoric acid. In the elemental analysis, the intensity of zirconium (depicting the residue of B-RCS)/zinc (depicting ZOE sealer) was very high on the dentin side treated with saline, in comparison to the dentin treated with polyacrylic and phosphoric acid. Furthermore, the intensity of elements from HVGIC was low on the dentin side of the groups with saline, whereas these elements showed maximum penetration into the dentin when treated with phosphoric acid.

Conclusion

Conditioning of the endodontic access cavity using 37% phosphoric acid immediately postobturation resulted in higher penetration of HVGIC into the dentin, in comparison to the other dentin conditioners.

A Comparative Study of the Marginal Fit of Endocrowns Fabricated From Three Different Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) Ceramic Materials: An In Vitro Study

INTRODUCTION

The marginal seal and adaptation are important factors for successful restoration. An inadequate marginal seal can lead to bacterial microleakage, plaque accumulation, and eventually treatment failure This in vitro study aimed to compare the marginal gap of endocrowns fabricated from three different computer-aided design/computer-aided manufacturing (CAD/CAM) ceramic materials.

METHODS

Thirty extracted mandibular molars were selected for the study. Endocrown preparations were completed after root canal treatment. Teeth were divided into three groups to receive endocrowns fabricated of lithium disilicate ceramic (IPS-e.max CAD, Ivoclar Vivadent AG, Schaan, Liechtenstein), zirconia-reinforced lithium silicate ceramic (VITA Suprinity®, VITA Zahnfabrik, Bad Säckingen, Germany), and polymer-infiltrated ceramic (VITA Enamic®, VITA Zahnfabrik). The digital impressions were transferred to the design software to construct the endocrowns. The endocrowns were milled and cemented. The marginal fit was examined using a digital camera stereomicroscope at a magnification of 80X. Images were transferred to Image-J software (National Institutes of Health, Bethesda, Maryland, United States) to measure the marginal gap.

RESULTS

One-way ANOVA showed a significant difference in the marginal gap between the different ceramic groups (P=0.006). Tukey's Honest Significant Difference (HSD) post-hoc test showed that VITA Suprinity had significantly higher gap width values than VITA Enamic (P=0.005). No significant differences in gap width values were found between VITA Enamic and IPS e.max CAD or between VITA Suprinity and IPS e.max CAD (P>0.05).

CONCLUSION

The marginal gap of endocrown restorations varies with different CAD/CAM materials (zirconia-reinforced lithium silicate glass-ceramic, polymer-infiltrated hybrid ceramic, and lithium disilicate glass-ceramic), but are all within clinically acceptable marginal gap width.

The Effect of Mineral Trioxide Aggregate Obturation Levels on the Outcome of Endodontic Retreatment: An Observational Study

INTRODUCTION

No clinical studies have examined the effect of mineral trioxide aggregate (MTA) obturation levels on the outcome of endodontic retreatment. This retrospective study examined treatment outcomes in three cohorts that compared overfilling, flush filling, and underfilling after orthograde retreatment using MTA.

METHODS

Two hundred fifty patients with 264 teeth diagnosed with previously treated root canals and apical periodontitis retreated in a private endodontic practice were included. All teeth received MTA obturation and the extent of the final filling level was measured in relation to the major apical foramen. After 6-month follow-ups, all nonhealing cases were treated surgically. After 24- to 72-month reviews, the effect of preoperative lesion size and the degree of MTA obturation level were assessed. Multiple linear regression and time-to-event analysis using Stata 17 software (StataCorp LLC, College Station, TX) were used to evaluate the data.

RESULTS

Within the three cohorts, 99 out of 108 overfilled teeth (91.7%), 90 out of 103 flush fills (87.4%), and 10 out of 53 underfilled teeth (18.9%) healed and were successfully retreated without surgery at 48-months. When surgical outcomes were included, the combined healed proportion was 93.2%. Preoperative lesion size was found to be an important predictor for retreatment nonhealing. A 1-mm increase in lesion size at baseline resulted in an estimated 11% (95% CI 1.04, 1.18)-38% (95% CI 1.22, 1.58) increase in the risk of surgery. Compared to overfilling and flush filling, underfilling was associated with an approximately three-fold increase in requiring surgery and characterized by delayed healing.

CONCLUSION

MTA obturation is a viable retreatment option for teeth with nonhealing endodontic treatment. MTA overfills or flush fillings do not adversely affect healing outcomes. However, MTA underfilling increases the chances for nonhealing and surgical intervention.

Clinical applications of calcium silicate-based materials: a narrative review

Calcium silicate-based materials are hydrophilic materials with biocompatibility and bioactivity properties. Despite many advantages, they might present some problems related to discolouration, setting time, manipulation and solubility depending on the composition of the product and the type of clinical application. Calcium silicate-based materials can be evaluated under two types according to their intended use: calcium silicate-based cements (CSCs) and calcium silicate-based sealers (CSSs). CSCs can be used in many endodontic procedures including perforation repair, resorption repair, apical barriers, guided endodontic repair, vital pulp treatment, endodontic surgery, root fractures and root canal filling as a core obturation material. CSSs are available for use with gutta-percha to obturate root canals using cold and warm techniques, including the sealer-based obturation technique. The purpose of this review is to evaluate the available literature on CSCs and CSSs and to provide up-to-date information and recommendations for their clinical applications.

Biological considerations of dental materials as orifice barriers for restoring root-filled teeth

There is ample published literature regarding the technical aspects of restoring root-filled teeth, but little concerning the biological impacts, consequences, and criteria for the selection of direct restorative materials following endodontic treatment. The provision of an effective coronal seal in addition to a sound root filling is known to be important in the prevention of root canal infection. This review seeks to explore the evidence concerning the selection of dental materials in the restoration of root-filled teeth, specifically with a close examination of the properties of commonly used materials as orifice barriers. © 2023 Australian Dental Association.