Marginal integrity in minimally invasive molar resin composite restorations: Impact of polymerization shrinkage

OBJECTIVES

This study utilized non-linear finite element (FE) models to explore polymerization shrinkage and its impact on marginal integrity in molars following both selective caries removal (SCR) and conventional treatment. Specifically, we performed 2D in silico simulations to study residual stresses post-resin polymerization shrinkage and their influence on the marginal integrity of various restoration types.

METHODS

Initially, FE models were developed based on a cohesive zone framework to simulate crack propagation along the bonded interfaces between restoration and tooth structure in SCR-treated molars with class I and class II restorations. The modeled resin composite restorations first underwent polymerization shrinkage and were then subjected to various occlusal loading conditions. Stress magnitudes and distributions were identified to evaluate the margin integrity and predict the mechanism and location of interfacial failure.

RESULTS AND DISCUSSION

The FE models computed polymerization shrinkage stresses of less than 1 MPa, exerting a minor influence on the composite/tooth interface. Occlusal loading, however, significantly impacted the load-bearing capacity of the composite/tooth (c/t) interface, potentially jeopardizing the restoration integrity. Especially under bi-axial occlusal loading, interfacial debonding occurred in the vertical cavity walls of the class I restorations, increasing the risk of failure. Notably, SCR-treated teeth exhibited better margin integrity than restored teeth after complete caries removal (NCR). These findings provide valuable insights into the mechanical behavior of SCR-treated teeth under different loading conditions and highlight the importance of considering the load scenarios that may lead to failure at the c/t interface. By investigating the factors influencing crack initiation and delamination, this novel research contributes to the optimization of restorative treatments and aids in the design of more resilient dental restorations.

Nd:YAG water mist laser treatment for giant gestational gingival tumor: A case report

BACKGROUND

This case of gestational gingival tumor is huge and extremely rare in clinical practice. As the growth location of this gingival tumor is in the upper anterior tooth area, it seriously affects the pregnant woman's speech and food, causing great pain to the patient. The use of Nd:YGA water mist laser to remove the gingival tumor resulted in minimal intraoperative bleeding, minimal adverse reactions, and good postoperative healing, which is worthy of clinical promotion and application.

CASE SUMMARY

The patient, a pregnant woman, reported a large lump in her mouth on the first day of postpartum treatment. Based on medical history and clinical examination, the diagnosis was diagnosed as gestational gingival tumor. Postoperative pathological biopsy also confirmed this diagnosis. The use of Nd:YAG water mist laser to remove the tumor resulted in minimal intraoperative bleeding, clear surgical field of view, short surgical time, and good postoperative healing.

CONCLUSION

In comparison to traditional surgery, Nd:YAG water mist laser surgery is minimally invasive, minimizes cell damage, reduces bleeding, ensures a clear field of vision, and virtually eliminates postoperative edema, carbonization, and the risk of cross infection. It has unique advantages in oral soft tissue surgery for pregnant patients. Therefore, the clinical application of Nd:YAG water mist laser for the treatment of gestational gingival tumors is an ideal choice.

Assessing dentists' awareness of the orthodontic-restorative interface

OBJECTIVES

Awareness of the interface between restorative and orthodontic treatments is essential for dentists to facilitate a meaningful interdisciplinary approach by integrating the knowledge and skills of different dental disciplines into patients' treatment to enhance outcomes. The aim of this study was to investigate General Dental Practitioners' (GDPs) awareness of the orthodontic-restorative interface.

METHODS

This was a mixed-method study involving the collection of a) quantitative data via a bespoke online questionnaire and b) qualitative data through open questions. A weblink was created to the questionnaire using Opinio®. The questionnaire was distributed to GDPs practising in the UK. Clinical vignette-based questions assessed GDPs awareness and the results were categorised into two groups: aware and unaware. Two months after the primary survey, respondents were sent an email with follow-up (reliability) survey. Reliability responses were compared against the primary responses to assess the repeatability using intraclass correlation coefficient. Data were analysed using independent t-test and X2 test.

RESULTS

118 complete responses were received. 63 GDPs (53.4 % [95 % CI 44 %-63 %]) demonstrated a good understanding of the orthodontic-restorative interface. These GDPs were characterised by greater age (t = 2.75, p = 0.007) and experience (t = 3.54, p < 0.001). Qualitative data showed that respondents perceived orthodontic-restorative treatments as minimally invasive and aesthetics enhancing.

CONCLUSIONS

Orthodontic-restorative treatment aids in minimal invasive dentistry. GDPs lack adequate awareness of the orthodontic-restorative interface in relation to patient care and communication with patients. More quality and structured undergraduate and postgraduate training are imperative to facilitate GDPs to understand and utilise aspects of orthodontic-restorative treatments to raise the standard of patient care. Additionally, to support these patients, the educational pathway between GDPs and specialist orthodontists is crucial.

CLINICAL SIGNIFICANCE

GDPs ability to assess and carry out orthodontic-restorative treatments would conserve natural teeth. Dependable access to orthodontic services would encourage GDPs to refer challenging cases to specialists or dentists with enhanced skills. When the circumstances call for it, patients should be given orthodontic-restorative alternatives, regardless of the potential consequences of their acceptance of the procedures.

Outcomes of resin-bonded attachments for removable dental prostheses

PURPOSE

This clinical study aimed to evaluate the outcomes of resin-bonded attachments (RBAs) for precision-retained removable dental prostheses (RDPs) after at least two years of clinical maintenance.

METHODS

Since December 1998, 205 RBAs (44 bonded to posterior teeth, 161 to anterior teeth) have been inserted in 123 patients (62 females and 61 males; mean age, 63.6 ± 9.6 years) who were recalled annually. The abutment teeth underwent a minimally invasive preparation limited to the enamel. RBAs were cast in a cobalt-chromium alloy with a minimum thickness of 0.5 mm and adhesively luted with a luting composite resin (Panavia 21 Ex or Panavia V5, Kuraray, Japan). We evaluated caries activity, plaque index, periodontal condition, and tooth vitality. The Kaplan-Meier survival curves were used to account for the reasons for failure.

RESULTS

The mean observation time of RBAs until the last recall visit was 84.5 ± 51.3 months (range, 3.6-270.6). During the observation period, 33 RBAs debonded in 27 patients (16.1%). The 10-year success rate according to the Kaplan-Meier analysis was 58.4%, which dropped to 46.2% after 15 years of observation if debonding was considered a failure. If rebonded RBAs were regarded as surviving, the 10- and 15-year survival rates would be 68.3% and 61%, respectively.

CONCLUSIONS

The use of RBAs for precision-retained RDPs appears to be a promising alternative to conventionally retained RDPs. As reported in the literature, the survival rate and frequency of complications were comparable with those of conventional crown-retained attachments for RDPs.

Biting and thermal sensitivity relief of cracked tooth restored by occlusal veneer: A 12-to 24 months prospective clinical study

OBJECTIVES

To analyze the relief time and risk factors of biting/thermal sensitivity in cracked tooth (CT) restored using occlusal veneer.

METHODS

63 CT were analyzed, and their demographic and clinical data and medical history were collected. Patients were followed-up to examine the relief of thermal/biting sensitivity.

RESULTS

The maxillary first molar was the most prevalent (N = 25, 40%). The number of crack lines on the finish line ranged from 1 to 6 while the number of crack lines through preparation on the finish line from 0 to 4. Pain relief achieved steadily to 52% for thermal and 62% for biting at 1 week to over 90% for each by 3 months and was completely resolved (no pain) for each by 12 months. Painful of lateral percussion was related to a long period of thermal sensitivity (≥1 month) after restoration with occlusal veneer. The number of crack lines through preparation on the finish line >2 was correlated with biting sensitivity (≥1 month) post-treatment.

CONCLUSIONS

Most patients (>90%) became asymptomatic of biting and thermal sensitivity within 3 months of CT restored by occlusal veneer. Lateral percussion and the number of crack lines through preparation on the finish line could be significant factors affecting postoperative symptoms.

CLINICAL SIGNIFICANCE

Occlusal veneer is an ultrathin restoration and had no need for restricting clinical crown height, which could protect and relief the biting/thermal sensitivity of CT without preventive root canal therapy.

Teaching of posterior composites for the restoration of permanent teeth in undergraduate dental training programmes: Systematic review and meta-analysis

OBJECTIVES

To systematically assess aspects of teaching of posterior composite restorations (PCRs) in permanent teeth in dental schools.

STUDY SELECTION

Quantitative studies reporting on dental schools' teaching regarding the placement of PCRs in permanent teeth. Random-effects meta-analyses and meta-regressions were performed. Risk of bias was assessed based on the Medical Education Research Study Quality Instrument (MERSQI).

SOURCES

Electronic databases (MEDLINE via PubMed, EMBASE via Ovid, Web of Science, and Scopus) were searched in January 2023.

DATA

Forty sources reporting on 34 studies having surveyed 1,286 dental schools were included. Overall, 92.7% (95%-CI: 88.2-95.5) of dental schools reported to teach PCRs. PCRs in three-surface Class II cavities are taught by 82.0% (95%-CI: 70.4-89.7). The mandatory use of liners in deep cavities is taught by 78.3% (95%-CI: 68.9-85.5), and 44.0% (95%-CI: 34.3-54.2) reported to teach bulk-fill composites. While most posterior restorations placed by students were composites (56.1%; 95%-CI: 46.0-65.8), 94.7% (95%-CI: 86.6-98.0) of dental schools (still) teach posterior amalgam restorations. The proportion of dental schools teaching PCRs in three-surface Class II cavities increased and the mean proportion of PCRs among all posterior restorations increased over time (padj.≤0.003).

CONCLUSIONS

The teaching of PCRs in dental schools around the world reflects the increased use of resin composite in clinical practice, with students in countries where dental amalgam continues to be used, placing more posterior composites than restorations of dental amalgam. The teaching of PCRs, which is anticipated to increase, will continue to be refined with further developments in adhesive materials, devices, instrumentation, and techniques.

CLINICAL SIGNIFICANCE

Graduating dentists can be expected to be familiar with the use of resin composites for the restoration of posterior teeth.

Preorthodontic dilacerated incisive crown modification in a pediatric patient: a case report

INTRODUCTION

Dental dilacerations are abrupt deviations of the longitudinal axis of the crown or root portion of the tooth, caused by traumatic axial displacement of previously formed hard tissue in relation to the developing soft tissue.

CASE PRESENTATION

We report a 13-year-old male patient in good general health who was referred for root canal treatment of 21, whose abnormal crown morphology impeded orthodontic treatment. He presented bilateral crown dilaceration at 11 and 21. We opted for a CAD-CAM milled veneer in 21 and semidirect warm composite veneer in 11. Follow-up and monitoring of the restoration was performed through .stl file analysis.

DISCUSSION

Crown dilaceration severity assessment is crucial for deciding upon the best treatment plan for each case. Additive restorative protocols, cone beam computed tomography (CBCT) and 3D digital model analysis were the most useful aids by providing key multidisciplinary information.

CONCLUSION

A multidisciplinary treatment workflow with a minimally invasive approach aided with digital tools such as CBCT and CAD-CAM technologies is useful to achieve successful and predictable outcomes in crown dilaceration cases.

Simplified Orthograde Apical Plug and Intra-Orifice Barriers for Resolving a Complex Endodontic Challenge: A Case Report

Successful endodontic treatments are contingent upon establishing a hermetic seal within the root canal system. This seal is pivotal in preventing/resolving apical periodontitis. This case report introduces a simplified orthograde apical plug and intra-orifice barrier technique as an effective alternative to previously unsuccessful invasive nonsurgical and surgical treatments. A 28-year-old patient presented with persistent discomfort and localized swelling in the furcation area of the mandibular left first molar. The tooth had previously undergone both root canal therapy and surgical retreatment. A distinctive feature of this case was the unconventional amputation of the mesial root, unlike conventional periradicular surgery or root amputation. This unusual scenario was accompanied by the presence of a large endodontic lesion. An apical plug, utilizing calcium-enriched mixture (CEM) cement, was placed, complemented by the use of CEM intra-orifice barriers to ensure the hermetic sealing of the entire root canal system. Long-term follow-up assessment demonstrated the complete healing of the preexisting large endodontic lesion. This case underscores the significance of proper diagnosis, right treatment planning, and considering conservative treatment options for complex cases, highlighting the pivotal role played by a reliable seal in achieving successful results in endodontic procedures.

Microabrasion in the management of enamel discolorations in paediatric dentistry: a systematic review

Structural abnormalities of the anterior teeth could be aesthetically compromising in young patients. The dentist must provide solutions while preserving dental tissue. Microabrasion approach can be a solution. We conducted a systematic literature review to evaluate whether microbrasion treatment in paediatric dentistry can improve aesthetic in cases of pre- or post-eruptive discolorations on tooth enamel. 741 articles published up to September 2021 were selected from 3 databases using the key word "microabrasion". 11 prospective studies including 6 randomized were relevant to the inclusion criteria. Microabrasion appears to be an effective and reliable technique for the management of pre and post enamel discoloration in paediatric dentistry, especially in fluorosis. More high-powered, well-conducted randomized studies with complete evaluation criteria are needed for other types of spots. Standardization of criteria for assessing treatment success and of the protocol required should be explored.

Clinical and Microbiological Assessment of Carisolv and Polymer Bur for Selective Caries Removal in Primary Molars

Aim and objective

To assess the efficacy of the new Carisolv system and Polymer bur (SmartbursII®) for selective caries removal in primary molars clinically and microbiologically, compared with the conventional mechanical method.

Materials and methods

Sixty children with class I active carious lesions were selected. The children were randomly allocated to three groups (n = 20) according to the caries removal method. Under rubber dam isolation, dentin samples were taken before and after caries removal for microbial culture. Time spent in each technique was recorded. The clinical efficacy of caries removal was verified using caries detector dye. Patient satisfaction toward the treatment was evaluated using a facial image scale.

Results

The median of caries detector dye scores was significantly lower in the conventional group compared to others (p value < 0.05). The mean time for caries removal was the longest with Carisolv (p value < 0.05). The median of facial image scale scores was significantly higher in the conventional group compared with others (p value < 0.05). The mean total viable bacterial count after caries removal was significantly higher in polymer bur group compared with others (p value < 0.05). While, there was no significant difference between Carisolv and conventional groups (p value > 0.05).

Conclusion

The clinical efficacy of caries removal was highest with the mechanical method. Carisolv took the longest time for caries removal. Patient satisfaction was higher with Carisolv and polymer bur than the mechanical method. The antimicrobial efficacy of Carisolv and the mechanical method was higher than the polymer bur.

Clinical significance

Carisolv is a viable alternative to the mechanical method in the management of dental caries, especially in children. Further studies are needed to assess the efficacy of caries removal by SmartbursII®.

How to cite this article

Asal MA, Abdellatif AM, Hammouda HE. Clinical and Microbiological Assessment of Carisolv and Polymer Bur for Selective Caries Removal in Primary Molars. Int J Clin Pediatr Dent 2021;14(3):357–363.

Artificial Saliva for Therapeutic Management of Xerostomia: A Narrative Review

In clinical practice, xerostomia or oral dryness is a chronic disease condition encountered by most dentists and dental hygienists, which often causes a negative impact on the oral health-related quality of life of the affected individual. Xerostomia is caused due to salivary gland dysfunction. It is related to reduced salivary secretion or the absence of saliva flow, more frequently, exhibits qualitative changes in saliva proteins and immunoglobulin concentrations that arise due to salivary gland dysfunction. This condition causes discomfort and interferes with normal oral activities, and affected individuals are at high caries risk. There are several options for treatment and symptom management: salivary stimulants, topical agents, saliva substitutes, and systemic sialogogues. This review explores the current status of therapeutic management of patients affected by xerostomia and hyposalivation using artificial saliva.

Selective Caries Removal in Permanent Teeth (SCRiPT) for the treatment of deep carious lesions: a randomised controlled clinical trial in primary care

BACKGROUND

Dental caries is one of the most prevalent non-communicable disease globally and can have serious health sequelae impacting negatively on quality of life. In the UK most adults experience dental caries during their lifetime and the 2009 Adult Dental Health Survey reported that 85% of adults have at least one dental restoration. Conservative removal of tooth tissue for both primary and secondary caries reduces the risk of failure due to tooth-restoration, complex fracture as well as remaining tooth surfaces being less vulnerable to further caries. However, despite its prevalence there is no consensus on how much caries to remove prior to placing a restoration to achieve optimal outcomes. Evidence for selective compared to complete or near-complete caries removal suggests there may be benefits for selective removal in sustaining tooth vitality, therefore avoiding abscess formation and pain, so eliminating the need for more complex and costly treatment or eventual tooth loss. However, the evidence is of low scientific quality and mainly gleaned from studies in primary teeth.

METHOD

This is a pragmatic, multi-centre, two-arm patient randomised controlled clinical trial including an internal pilot set in primary dental care in Scotland and England. Dental health professionals will recruit 623 participants over 12-years of age with deep carious lesions in their permanent posterior teeth. Participants will have a single tooth randomised to either the selective caries removal or complete caries removal treatment arm. Baseline measures and outcome data (during the 3-year follow-up period) will be assessed through clinical examination, patient questionnaires and NHS databases. A mixed-method process evaluation will complement the clinical and economic outcome evaluation and examine implementation, mechanisms of impact and context. The primary outcome at three years is sustained tooth vitality. The primary economic outcome is net benefit modelled over a lifetime horizon. Clinical secondary outcomes include pulp exposure, progession of caries, restoration failure; as well as patient-centred and economic outcomes.

DISCUSSION

SCRiPT will provide evidence for the most clinically effective and cost-beneficial approach to managing deep carious lesions in permanent posterior teeth in primary care. This will support general dental practitioners, patients and policy makers in decision making. Trial Registration Trial registry: ISRCTN.

TRIAL REGISTRATION NUMBER

ISRCTN76503940. Date of Registration: 30.10.2019. URL of trial registry record: https://www.isrctn.com/ISRCTN76503940?q=ISRCTN76503940%20&filters=&sort=&offset=1&totalResults=1&page=1&pageSize=10&searchType=basic-search .

Long-term treatment costs and cost-effectiveness of restoration repair versus replacement

OBJECTIVES

When managing partially defective restorations, dentists can choose between repair and replacement. We aimed to assess the long-term treatment costs of repairs and replacements.

METHODS

Partially defective anterior and posterior composite restorations in permanent teeth had been repaired or replaced in a German university hospital and were retrospectively followed until censoring or one of the following events: (1) Extraction, (2) Major complications including placement of indirect restorations, endodontic treatments and extractions, or (3) Any complications including major complications and further direct restorations. Costs were estimated from a German mixed public-private-payer perspective. Cost-effectiveness differences were described using median-based incremental-cost-effectiveness ratios (ICER_MEDIAN). Statistical analysis was performed using generalized linear mixed modeling (GLM), Chi²-test, and Wilcoxon rank-sum test (p < 0.05).

RESULTS

A total of 616 repairs in 468 patients (follow-up: 4.9 ± 4.1 years) and 264 replacements in 218 patients (follow-up: 4.8 ± 4.3) were included. While replacements were associated with higher initial treatment costs, median annualized treatment costs did not significantly differ between repair (47.58 Euro [IQR: 24.41-107.04]) and replacement (50.64 Euro [IQR: 26.30-118.78]; p > 0.05), but were higher for molars (75.53 Euro [IQR: 24.41-92.18]) than incisors (45.03 Euro [IQR: 28.19-168.50]; p = 0.011). The difference in the % of extractions, major and any complications were minimal between both groups. The mean ICER_MEDIAN of replacement vs. repair was -146.8 Euro/% when extractions were considered as outcomes. Regarding major and any complications, mean ICER_MEDIAN amounted to 67.6 Euro/% and 23.9 Euro/%, respectively.

SIGNIFICANCE

Repairs and replacements of partially defective restorations showed similar long-term costs and cost-effectiveness.

Biochemical characterisation of carious dentine zones using Raman spectroscopy

OBJECTIVE

Carious tissue discrimination in clinical operative caries management relies traditionally on the subjective hardness of carious dentine. Biochemical alterations within the lesion have the potential to discriminate the lesion zones objectively. This study aimed to determine the correlation between the biochemical proportions of amide I and phosphate moieties as these are the most prominent peaks found in dentine with the Knoop microhardness of carious dentine zones, using non-contact Raman spectroscopy. The null hypothesis investigated was that there was no correlation between Raman peak ratios, amide I: phosphateν1, and the Knoop microhardness within specific zones of a carious lesion.

METHODS

423 scan points from 20 carious dentine lesion samples examined using high-resolution Raman spectroscopy. The peak ratio of the characteristic vibration mode of amide I (1650 cm^-1) and phosphate (960 cm^-1) bands were calculated, following a straight line path through the lesion to the pulp and correlated to corresponding Knoop microhardness measurements.

RESULTS

Using logistic regression analysis, clear correlations were found between the Knoop microhardness and Raman peak ratio cut-off values between caries-infected and caries-affected dentine (81.5 % sensitivity / 92.7 % specificity), with a lower specificity (2.7 %) found between caries-affected and sound dentine.

CONCLUSION

This study concluded that non-contact Raman spectroscopy can be used in vitro to discriminate objectively between the different zones of a carious dentine lesion at high resolution, using the Raman peak ratios, amide I : phosphate ν₁.

CLINICAL SIGNIFICANCE

Specific biochemical alterations have the potential to be used in-vitro and in-vivo to identify the end-point of selective carious lesion excavation.

A 24-month randomized controlled trial on the success rates of restoring untreated and SDF-treated dentine caries lesions in primary teeth with the ART approach

OBJECTIVE

To compare the success rates of restoring untreated and SDF-treated dentine caries lesions in primary teeth with atraumatic restorative treatment (ART) approach.

METHOD

Cavitated dentine caries lesions in preschool children were randomly allocated to two groups to be applied with either 38% silver diamine fluoride (SDF) solution or tonic water (control) ten weeks before being restored with the ART approach. Status of the restorations were assessed every six months by a blinded independent examiner. Multilevel logistic regression and multilevel survival analyses were conducted to assess the restoration success rates.

RESULTS

A total of 194 children (SDF group, 101; control group, 93) were included, with 260 and 249 ART restorations placed in the SDF and the control groups, respectively. At 24-month follow-up, 88 (87 %) and 84 (90 %) children remained in the SDF and the control groups, respectively. There was no significant difference between the ART restoration success rates of the two study groups (p > 0.05). The success rate of ART restorations was associated with the class of restorations. Class I restorations had the highest success rate (∼50 %), followed by Class V (∼35 %), Class II (∼15 %) and Class III (<10 %). Besides, the mean time used to place an ART restoration in a SDF-treated caries lesion was shorter than that in untreated lesion (4.8 vs. 5.1 min, p = 0.006).

CONCLUSION

Prior SDF application does not significantly affect the success rate of ART restorations placed in primary teeth. Besides, it is faster to place ART restorations in caries lesions that have been previously treated with SDF.

CLINICAL SIGNIFICANCE

Prior application of silver diamine fluoride solution on cavitated dentine caries lesions in primary teeth can shorten the average time required to place an ART restoration while not jeopardizing the success rate of the restorations.

Comparing the efficacies of two chemo-mechanical caries removal agents (2.25% sodium hypochlorite gel and brix 3000), in caries removal and patient cooperation: A randomized controlled clinical trial

INTRODUCTION

This study compared and evaluated the effectiveness of Brix 3000 and 2.25 % sodium hypochlorite (NaOCl) gel with conventional rotary instrumentation method in caries excavation of primary molars. The null hypothesis: no difference between the two tested chemo-mechanical caries removal (CMCR) agents used in this trial.

MATERIALS AND METHODS

a randomized controlled clinical trial conducted with 32 children suffering from proximal caries of primary maxillary molars, age ranging between 6 and 9 years old. Subjects were randomly assigned into three groups: Brix 3000, NaOCl gel, and conventional with 10, 12, and 10 teeth in each group, respectively. After isolation of selected teeth, either CMCR agent were applied for two minutes. The application was repeated as needed until a caries-free surface was obtained. The conventional group used low-speed burs to excavate all carious lesions. The time required to obtain a caries-free result for each testing method was recorded. Wong-Baker FACES pain rating scale was used to assess the acceptance of the technique used by the child.

RESULTS

Conventional treatment required significantly less time for caries removal compared to Brix 3000 (P = .002) and NaOCl gel (P = .000). No significant difference observed between Brix 3000 and NaOCl gel (P = .679). Statistically higher pain scores were observed with conventional treatment compared to both Brix 3000 (P = .000) and NaOCl gel (P = .005). Pain scores were lower with Brix 3000, and NaOCl gel with no significant difference observed between the CMCR agents (p = .690).

CONCLUSIONS

CMCR agents that are effective in removing the carious dentine of primary teeth without negatively affecting the cooperation of children.

CLINICAL SIGNIFICANCE

The use of a 2.25 % sodium hypochlorite gel can be an effective and well-tolerated method of removing decay from primary teeth and reduce the trauma associated with conventional rotary caries removal.

A randomised controlled study on the effects of different surface treatments and adhesive self-etch functional monomers on the immediate repair bond strength and integrity of the repaired resin composite interface

OBJECTIVES

To evaluate the effects of different surface conditioning methods on the immediate repair bond strength and integrity of the repaired composite interface.

METHODS

One hundred and five resin composite blocks made of a nanohybrid resin composite were randomly assigned to one of the following surface conditioning groups (n = 15/group): Group 1: Gluma Self Etch™ adhesive system, Group 2: Tokuyama Bond Force II™ adhesive system, Group 3: non-roughened and non-conditioned surfaces, Group 4: sandblasting and Gluma Self Etch™, Group 5: sandblasting and Tokuyama Bond Force II™, Group 6: sandblasting only. A positive control group was also used. Resin composite identical to the substrate was applied and the repaired specimens were subjected to shear bond strength (SBS) testing. Representative samples from all groups were subjected to scanning electron microscopy and surface profilometry to determine their mode of failure. The data were analysed statistically using Analysis of Variance (ANOVA) and two independent sample t-test (α = 0.05).

RESULTS

The mean SBS of all test groups ranged between 1.92 and 5.40 MPa and varied with the degree of composite surface roughness and the type of adhesive system employed. Significantly highest SBS values (5.40 ± 0.36 MPa) were obtained in Group 5 (p = 0.017) which were comparable to the coherent strength of the resin composite in the positive control group (p > 0.05).

CONCLUSIONS

Under the tested conditions, significantly greater SBS of repaired resin composite was achieved when the substrate surface was conditioned by sandblasting followed by the application of the Tokuyama Bond Force II™ adhesive system.

CLINICAL SIGNIFICANCE

Effecting a repair of a nanohybrid composite restoration with sandblasting and the application of TBF II would seem to enhance the interfacial bond strength and integrity of the repaired resin composite interface. Clinical trials are necessary to determine the usefulness of this technique.

Same, same, but different? A systematic review of protocols for restoration repair

OBJECTIVES

While repairs are increasingly recommended to manage partially defective restorations, performing the repair (including bonding to different substrates) can be challenging, and dentists should adhere to established repair protocols. We aimed to systematically assess the consistency and quality of repair protocols.

DATA

808 records were initially identified and 71 repair protocols based on 84 sources included. The number of published sources over time increased exponentially (p < 0.001). Recommended treatment steps varied widely. Some treatment steps were only recommended by a minority of protocols, while others were consistently recommended (e.g. surface roughening, hydrofluoric acid etching of silicate ceramics, application of an adhesive/bonding agent). The overall quality of included sources was moderate (mean ± SD 3.7 ± 0.9 out of 7 points).

SOURCES

Electronic databases (Medline via PubMed, Embase) were searched, hand searches using Google and Google Scholar conducted, and the reference lists of included full texts screened and cross-referenced.

STUDY SELECTION

(Non-)systematic reviews, working instructions, and textbooks with protocols on direct composite repair restorations for partially defective (1) composite, (2) amalgam, (3) porcelain-fused-to-metal (PFMs) with exposed metal base, (4) ceramic/PFMs without exposed metal base, and (5) full metal restorations were included. Data synthesis was performed by tabulation of recommended treatment steps and descriptive statistics. The quality of included sources was assessed based on a checklist for guideline appraisal (MiChe).

CONCLUSIONS

The main treatment steps were consistently reported across repair protocols.

CLINICAL SIGNIFICANCE

Dentists may want to adopt widely recommended treatment steps when performing repairs of different restoration materials in their daily practice.

An integrated multifunctional hybrid cement (pRMGIC) for dental applications

OBJECTIVE

Glass-ionomer and resin-modified glass-ionomer cements are versatile materials with the ability to form a direct bond with tooth tissues. The aim of this study was to formulate a novel class of dental bio-interactive restorative material (pRMGIC) based on resin-modified glass-ionomer cements via the inclusion of an organophosphorus monomer, ethylene glycol methacrylate phosphate, with a potential to improve the mechanical properties and also function as a reparative restorative material.

METHODS

pRMGIC was formulated with modification of the resin phase by forming mixes of ethylene glycol methacrylate phosphate (EGMP; 0-40%wt) and 2-hydroxyethyl methacrylate monomer into the liquid phase of a RMGIC (Fuji II LC, GC Corp.). The physical properties of the cements were determined including setting characteristics, compressive strength and modulus (CS &CM), microhardness (MH) and biaxial flexural strength (BFS). Fluid uptake and fluoride release were assessed up to 60 days storage. Adhesion to sound dentine was measured using micro-tensile bond strength and surface integrity was analysed using SEM coupled with EDX. Statistical analysis was performed using ANOVA and Bonferroni post-hoc tests.

RESULTS

The pRMGIC cements exhibited an increase in working time with increasing EGMP concentration however were within the limits of standard clinical requirements. Although the compressive strength of pRMGIC cements were comparable to control cements in the early stages of maturation, the higher EGMP-containing cements (EGMP30 and 40) exhibited significantly greater values (p < 0.05) after 4 weeks storage (141.0 ± 9 and 140.4 ± 8 MPa, respectively), in comparison to EGMP0 (128.8 ± 7 MPa). A dramatic two fold increase in biaxial flexural strength (p < 0.001) was observed for the pRMGIC's. Furthermore, the ability to decalcify tooth apatite resulted in enhanced interfacial adhesion due to chelation with calcium ions of tooth apatite. The inclusion of EGMP encouraged formation of reinforcing complexes within the RMGIC, thus improving physical properties, decreasing solubility and lower fluoride release. A dense microstructure was observed with increasing EGMP content.

SIGNIFICANCE

A novel universal bio-interactive adhesive repair material will enable clinicians to offer more effective repair of the tooth-restoration complex, thus future treatments will benefit both patient and a severely constrained healthcare budget.

Integrating the PILP-mineralization process into a restorative dental treatment

The addition of charged polymers, like poly-aspartic acid (pAsp), to mineralizing solutions allows for transport of calcium and phosphate ions into the lumen of collagen fibrils and subsequent crystallization of oriented apatite crystals by the so-called Polymer-Induced Liquid Precursor (PILP) mineralization process, leading to the functional recovery of artificial dentin lesions by intrafibrillar mineralization of collagen.

OBJECTIVE

To evaluate the feasibility of applying the PILP method as part of a restorative treatment and test for effectiveness to functionally remineralize artificial lesions in dentin.

MATERIALS AND METHODS

Two methods of providing pAsp to standardized artificial lesions during a restorative procedure were applied: (A) pAsp was mixed into commercial RMGI (resin modified glass ionomer) cement formulations and (B) pAsp was added at high concentration (25mg/ml) in solution to rehydrate lesions before restoring with a RMGI cement. All specimens were immersed in simulated body fluid for two weeks to allow for remineralization and then analyzed for dehydration shrinkage, integrity of cement-dentin interface, degree of mineralization, and changes in the nanomechanical profile (E-modulus) across the lesion.

RESULTS

After the remineralization treatment, lesion shrinkage was significantly reduced for all treatment groups compared to demineralized samples. Pores developed in RMGI when pAsp was added. A thin layer at the dentin-cement interface, rich in polymer formed possibly from a reaction between pAsp and the RMGI. When analyzed by SEM under vacuum, most lesions delaminated from the cement interface. EDS-analysis showed some but not full recovery of calcium and phosphorous levels for treatment groups that involved pAsp. Nanoindentations placed across the interface indicated improvement for RMGI containing 40% pAsp, and were significantly elevated when lesions were rehydrated with pAsp before being restored with RMGI. In particular the most demineralized outer zone recovered substantially in the elastic modulus, suggesting that functional remineralization has been initiated by pAsp delivery upon rehydration of air-dried demineralized dentin. In contrast, the effectiveness of the RMGI on functional remineralization of dentin was minimal when pAsp was absent.

SIGNIFICANCE

Incorporation of pAsp into restorative treatments using RMGIs promises to be a feasible way to induce the PILP-mineralization process in a clinical setting and to repair the structure and properties of dentin damaged by the caries process.

Reparative Dentistry: Possibilities and Limitations

Purpose of Review

Defective dental restorations are amongst the most common encounters in general dental practice. Replacement of defective restorations is often costly and commonly results in the sacrifice of sound tooth structure, thereby compromising the vitality of the dental pulp, potentially resulting in the acceleration of the restoration cycle and premature loss of the restored tooth. With advances in adhesive dentistry, ‘reparative dentistry’ is becoming an important area of minimally invasive dentistry. This article highlights the detrimental biological effects of restoration replacement and provides an overview of current knowledge and understanding of restoration repair as a safe and effective alternative approach to replacement.

Recent Findings

The literature reviewed showed that a growing body of evidence from clinical studies indicates that repaired restorations have similar survival outcomes in patients with low and medium caries risk compared to replaced restorations and are clinically acceptable over a 12-year follow-up of clinical service. Teeth with repaired restorations are less likely to require aggressive interventions such as endodontic treatment or extraction compared to those with replaced restorations.

Summary

Repair options should be carried out wherever possible as minimally interventional procedures in order to increase the longevity of the remaining part of the restoration and the restored tooth unit. Restoration replacement should be considered as the last resort when there are no other viable alternatives.

Minimally Invasive Intervention for Primary Caries Lesions: Are Dentists Implementing This Concept?

Contemporary minimally invasive treatment concepts for restorative treatment of primary caries lesions include both delayed intervention and smaller-sized preparations restricted to removal of carious tissue. The aim of this study was to investigate whether these concepts have resulted in a trend towards a more conservative choice made by dentists regarding treatment thresholds and restorative techniques. The results from previously conducted, precoded questionnaires developed by Espelid and Tveit, as well as from a recent Dutch questionnaire, were collected and analysed. A worldwide trend towards more minimally invasive strategies in the operative treatment of caries lesions could not be observed, neither for the initiation of operative treatment nor for the preparation techniques. However, in some countries, changes over time could be assessed, especially in Norway, where a reduction in the proportion of interventions is visible for both occlusal and approximal lesions, indicating that more dentists are postponing interventions until the lesions have progressed to a deeper level. From the Dutch national survey, it could be concluded that operators that intervene at an earlier stage of approximal lesioning (stage ≤4) also intervene at an earlier stage of occlusal caries (stage ≤3) (p = 0.012; OR = 2.52; 95% CI: 1.22-5.22). Generally, it can be concluded that dentists worldwide still tend to operatively intervene at a too early stage of caries, although variations exist between countries. A worldwide shift could be observed in the restorative material applied, since composite resin has almost completely replaced amalgam for restoring primary caries lesions.

Management of dental erosion induced by gastro-esophageal reflux disorder with direct composite veneering aided by a flexible splint matrix

Dental erosion is frequently overlooked in clinical practice. The management of erosion-induced damage to the dentition is often delayed, such that extensive occlusal rehabilitation is required. These cases can be diagnosed by a careful clinical examination and a thorough review of the patient's medical history and/or lifestyle habits. This case report presents the diagnosis, categorization, and management of a case of gastro-esophageal reflux disease-induced palatal erosion of the maxillary teeth. The early management of such cases is of utmost importance to delay or prevent the progression of damage both to the dentition and to occlusal stability. Non-invasive adhesively bonded restorations aid in achieving this goal.

Approximate relative fatigue life estimation methods for thin-walled monolithic ceramic crowns

OBJECTIVES

The objective is to establish an approximate relative fatigue life estimation method under simulated mastication load for thin-walled monolithic restorations.

METHODS

Experimentally measured fatigue parameters of fluormica, leucite, lithium disilicate and yttrium-stabilized zirconia in the existing literature were expressed in terms of the maximum cyclic stress and stress corresponding to initial crack size prior to N number of loading cycles to assess their differences. Assuming that failures mostly originate from high stress region, an approximate restoration life method was explored by ignoring the multi-axial nature of stress state. Experiments utilizing a simple trilayer restoration model with ceramic LD were performed to test the model validity.

RESULTS

Ceramic fatigue was found to be similar for clinically relevant loading range and mastication frequency, resulting in the development of an approximate fatigue equation that is universally applicable to a wide range of dental ceramic materials. The equation was incorporated into the approximate restoration life estimation, leading to a simple expression in terms of fast fracture parameters, high stress area ΔA, the high stress averaged over ΔA and N. The developed method was preliminarily verified by the experiments. The impact of fast fracture parameters on the restoration life was separated from other factors, and the importance of surface preparation was manifested in the simplified equation. Both the maximum stress and the area of high stress region were also shown to play critical roles.

SIGNIFICANCE

While nothing can replace actual clinical studies, this method could provide a reasonable preliminary estimation of relative restoration life.

Understanding the management and teaching of dental restoration repair: Systematic review and meta-analysis of surveys

OBJECTIVES

Repair instead of complete replacement is recommended to manage partially defective restorations. It is unclear if and why such treatment is taught at dental schools or practiced by dentists. We aimed to identify barriers and facilitators for repairs using a systematic review and meta- and qualitative analysis.

SOURCES

Electronic databases (PubMed, CENTRAL, Embase, PsycINFO) were searched.

STUDY SELECTION

Quantitative studies reporting on the proportion of (1) dentists stating to perform repairs, (2) dental schools teaching repairs, (3) failed restorations having been repaired were included. We also included qualitative studies on barriers/facilitators for repairs. Random-effects meta-analyses, meta-regression and a thematic analysis using the theoretical domains framework were conducted.

DATA

401 articles were assessed and 29, mainly quantitative, studies included. 7228 dentists and 276 dental schools had been surveyed, and treatment data of 30,172 restorations evaluated. The mean (95% CI) proportion of dentists stating to perform repairs was 71.5% (49.7-86.4%). 83.3% (73.6-90.0%) of dental schools taught repairs. 31.3% (26.3-36.7%) of failed restorations had been repaired. More recent studies reported significantly more dentists to repair restorations (p=0.004). Employment in public health practices and being the dentist who placed the original restoration were facilitators for repairs. Amalgam restorations were repaired less often, and financial aspects and regulations came as barriers.

CONCLUSIONS

While most dentists state to perform repairs and the vast majority of dental schools teach repairs, the proportion of truly repaired restorations was low. A number of interventions to implement repair in dental practice can be deduced from our findings.

CLINICAL SIGNIFICANCE

Partially defective restorations are common in dental practice. While repairs are taught and dentists are aware of the recommendation towards repairs, the actually performed proportion of repairs seems low.

Preventive and Therapeutic Proximal Sealing: A 3.5-Year Randomized Controlled Clinical Trial Follow-Up

OBJECTIVE

The aim of this split-mouth, randomized controlled clinical trial was to evaluate the efficacy of proximal sealing for avoiding the development of new caries lesions or arresting incipient caries lesions on the mesial surface of first permanent molars (6m) abutting lesions on the distal surface of second primary molars (05d) in children at high caries risk.

METHODS

A total of 61 children 8-10 years old were selected based on the caries status of the proximal sites of 05d and 6m. Children with caries on 05d and caries-free 6m were placed in the preventive sealing group and children with caries on both 05d and 6m in the therapeutic group. The children in each group had one 6m surface pair and in each pair one 6m surface was randomly allocated to receive a preventive or therapeutic sealing. Using a split-mouth design, the other 6m surface in the pair served as control.

RESULTS

After 3.5 years, standardized follow-up radiographs were obtained for the 45 children who remained. In the preventive sealing group, 4 out of 30 (13.3%) sealed and 16 out of 30 (53.3%) unsealed sound 6m surfaces had developed new caries lesions (p = 0.004, McNemar test). In the therapeutic sealing group, the progression of the carious lesions on 6m was observed in 3 out of 15 sealed (20.0%) and 8 out of 15 (53.3%) unsealed caries control surfaces (p = 0.06).

CONCLUSIONS

Preventive sealing on sound 6m surfaces abutting 05d lesions in children at high caries risk efficaciously prevents the development of caries lesions. Therapeutically sealing active non-cavitated caries lesions reduces the progression.

Update on nonsurgical, ultraconservative approaches to treat effectively non-cavitated caries lesions in permanent teeth

Dental caries on tooth surfaces is still a problem in many industrialized countries. For many years, dentistry was influenced by a mechanical approach characterized by the use of high-speed rotary cutting instruments, and dentists predominantly used surgical methods to address caries. This included radical removal of diseased portions of the tooth, along with material-driven geometric extensions to areas that were assumed to be caries-resistant. This concept of extension for prevention was introduced by G. V. Black and influenced dentists for more than 120 years. Recently, a new paradigm of operative conservatism, sometimes referred to as "minimally invasive dentistry," has gained popularity. This paradigm is designed to promote maximum preservation of healthy dental structures over a lifetime. The aim of this review is to discuss the efficacy of current nonsurgical treatments for non-cavitated caries lesions in permanent teeth. Based on results obtained from clinical trials, this review evaluates treatments such as consumption of CPP-ACP added gums, resin infiltration and fissure sealing. Although in a few cases an invasive approach is needed to arrest caries progression, the non-surgical approach generally provides potential benefits that include conserving structure by delaying intervention or minimizing the operative procedure. All current non-invasive methods are effective in treating non-cavitated caries lesions. The adoption of non-invasive approaches in the management of these lesions can preserve dental tissues, thus increasing tooth longevity.