Natural history of periodontal disease: The original Sri Lanka and Oslo studies

Susceptibility to periodontal disease depends on individual factors within the host response to the bacterial challenge. The study of these factors requires longitudinal studies of an undisturbed development of the disease process. On the basis of the original longitudinal studies on the natural histology of periodontal disease staged in Sri Lanka and Oslo/Norway, several analyses of periodontal parameters and tooth status have been performed. The main findings were that in the first 20 years of complete absence of oral hygiene practices or preventive services attachment was lost at various rates. Three groups of subjects could be identified: rapidly progressing (RP) (8%), moderately progressing (MP) (81%), and subjects with no disease progression (NP) (11%). In the second two decades, the RP subjects have lost most of their teeth and no NP patients were identified anymore. The progression rate in these two decades was much slower, and the tooth mortality decreased. It could be predicted that subjects who had lost more than 2 mm at age 30 would not maintain a functional dentition at age 60. The corresponding control population in Oslo was used to study the influence of gingival inflammation on the initiation and progression of periodontal disease. The pattern and rates of attachment loss were identified in a population that was exposed to optimal and regular preventive services from age 3 onward. In the observation period of 26 years, it could be demonstrated that gingival inflammation varied little throughout adult life and always bleeding sites occurred consistently in 10% to 20%. The role of ongoing gingivitis in the pathogenesis of attachment loss was identified and also reflected stability whenever it was absent. Tooth mortality was only found in subjects with ongoing gingivitis. After 50 years of tooth age, 63% of the teeth were still maintained, while 99.8% were maintained after 50 years when gingival inflammation had been absent. Consequently, continuous gingivitis represented a risk factor for tooth loss.

Clinical evaluation of a novel protocol for supportive periodontal care: A randomized controlled clinical trial

BACKGROUND

The aim of this study was to compare the clinical efficacy and the patient perception of subgingival debridement with either guided biofilm management (GBM) or conventional scaling and root planing (SRP) during supportive periodontal care (SPC).

METHODS

Forty-one patients in SPC were randomly assigned to either treatment with GBM or SRP every 6 months. The primary outcome was the percentage of bleeding on probing (BoP) at 1 year. Moreover, pocket probing depths (PPD), recession, and furcation involvements were also measured. Full-mouth and specific site analyzes were performed at baseline, 6 and 12 months of SPC. Patient comfort was evaluated using a visual analogue scale (VAS) at 12 months.

RESULTS

At 1 year, mean BoP percentage decreased from 12.2% to 9.0% (p = 0.191) and from 14.7% to 7.9% (p = 0.004) for the GBM and SRP groups, respectively. Furcation involved multirooted teeth but no through-and-through lesions were significantly fewer in the GBM than in the SRP group after 12 months (p = 0.015). The remaining parameters showed slight improvement in both groups without any statistically significant differences between the two groups after 1 year. Pain evaluation as patient reported outcome measures (pain evaluation) was in favor (p = 0.347) of the SRP group, while overall satisfaction was similar for both groups. Treatment time was not statistically significantly different between the two groups (p = 0.188).

CONCLUSION

In well-maintained SPC patients, SRP protocols resulted in significant clinical improvements in terms of BoP; however, for the other clinical improvements, similar efficacy for both GBM and SRP was observed.

Clinical and histologic evaluation of heterotopic mucosa transpositioning at teeth and dental implants

AIM

To investigate the healing after heterotopic mucosa transpositioning at dental implants and teeth.

MATERIALS AND METHODS

One hemimandible per dog (n = 4) was allocated to receive 3 implants (test), whereby 3 premolars on the contralateral side served as controls. After osseointegration, a Z-plasty was performed on the buccal aspect of the test and control sites to heterotopically move the zone of keratinized tissue (KT) into a region with non-keratinized tissue (nKT) and vice versa. Clinical measurements were performed before (T0) and at 12 weeks following heterotopic transposition (T1). Thereafter, specimens were processed for histological analysis.

RESULTS

Clinical measurements revealed that at T1, a band of KT was reestablished at teeth (mean: 2.944 ± 1.866 mm), whereas at implants, the transpositioned nKT resulted in a mucosa without any signs of keratinization (mean: 0 mm; p < .0001). At implant sites, the probing attachment level loss was more pronounced compared to tooth sites (-1.667 ± 1.195 mm and -1.028 ± 0.878 mm, respectively; p = .0076). Histologically, the transpositioned nKT, was accompanied by the formation of KT at the tooth but not at implant sites. The supracrestal soft tissues were statistically significantly higher at tooth compared to implant sites (2.978 ± 0.483 mm and 2.497 ± 0.455 mm, p = .0083). The transpositioned KT remained mostly unaltered in its morphological characteristics.

CONCLUSIONS

The findings of this study indicate that: (a) transpositioned KT may retain its morphological characteristics; and (b) transpositioned nKM was accompanied by the formation of KT at the tooth but not at implant sites.

Randomized multicenter study on the plaque removal efficacy of 2 interdental brushes around the base of orthodontic brackets

INTRODUCTION

The objective of this multicenter study was to analyze the efficacy of cleaning 2 interdental brushes (IDBs) around brackets in patients with fixed orthodontic appliances.

METHODS

The study design was a multicenter, randomized, examiner-blinded crossover study with 3 interventions, the first of which was a baseline intervention. This study included 20 patients (12 females, 8 males) aged 12-18 years with fixed orthodontic devices examined at the Department of Orthodontics, University Medical Center of the Johannes Gutenberg University Mainz, and the Children's Dental Clinic St. Gallen. The outcome was a conventional, cylindrically shaped IDB (IDBG-S [IB]; Top Caredent GmbH, Schönau, Germany) was examined in comparison with an innovative waist-shaped IDB (Circum, CDB-8 [CB]; Top Caredent GmbH). The participants did not use the IDB themselves. The brushing procedure was performed professionally by 1 operator (C.E.). Each buccal tooth surface with a bracket was split into 8 areas, the main areas being 1 and 8. These main areas, which were difficult for toothbrushes to reach, were mesial (area 1) and distal (area 8) of the bracket edges in the gingival direction. Plaque index (PI) scores were assessed at 2 examinations before and after the cleaning procedure on 8 tooth surfaces in the area with orthodontic brackets. A computer-generated program randomly allocated the IDB sequence to the participants. Examiners (L.Z.-G. and Y.W.) assessing the outcomes were blinded to the intervention and the randomized allocation of participants to the different IDBs.

RESULTS

Both IDBs showed a plaque removal effect (CB, 0.68 [interquartile range, 0.63-0.77]; IB, 0.43 [interquartile range, 0.33-0.55]). The difference between the 2 IDB was statistically significant (P = 0.002). In particular, the CB yielded a higher plaque removal efficacy (CB effect, 0.68; IB effect, 0.21) at the main areas 1 and 8, which were difficult to reach. Ten participants were randomized to each sequence, and all 20 completed the study. No side effects or adverse events were reported or observed.

CONCLUSION

The waist-shaped brush head of the CB significantly enhanced plaque reduction in total and particularly in problem areas.

REGISTRATION

This trial was registered at the German Clinical Trials Registry (no. DRKS00014088; https://www.drks.de/drks_web/navigate.xxdo?navigationId=trial.HTML&TRIAL_ID=DRKS00014088) PROTOCOL: The protocol was not published before trial commencement.

FUNDING

This study was supported by the manufacturer Top Caredent GmbH, Schönau, Germany, which provided all interdental brushes used in this study.

Spontaneous regeneration of keratinized tissue at implants and teeth

AIM

To investigate the spontaneous regeneration of the implanto-mucosal and dento-gingival unit after complete removal of keratinized tissue (KT).

MATERIALS AND METHODS

One hemi-mandible per dog (n = 4) was allocated to receive three dental implants (test sites, premolar region), whereas three premolars on the contralateral side were controls. After osseointegration, the entire KT (buccal + lingual) was surgically excised on all test and control sites, leaving the bone exposed. Clinical measurements were performed before excision (T0 ) and after 12 weeks (T1 ). Following healing, the animals were euthanized, and the specimens were histologically processed. Descriptive statistical analyses were performed.

RESULTS

Clinical measurements revealed that at T1 , on all teeth, a band of KT was spontaneously regenerated (mean width: 2.60 ± 0.66 mm), whereas on implants, KT was detected only occasionally at mesial or distal but not at buccal sites (mean total: 0.35 ± 0.53 mm; p < .0001). Histologically, spontaneous regeneration of the dento-gingival unit was evident, displaying masticatory mucosa. At the implant sites, on the other hand, the implanto-mucosal unit was characterized by a non-keratinized epithelium and elastic fibres, indicating the characteristics encountered in alveolar mucosa.

CONCLUSION

After excision of KT at implant sites, the spontaneous regeneration of the soft tissue is characterized by a non-keratinized epithelium typical for alveolar mucosa, while at tooth sites the spontaneous regeneration was characterized by soft tissue resembling gingiva.

Clinical periodontal diagnosis

Periodontal diseases include pathological conditions elicited by the presence of bacterial biofilms leading to a host response. In the diagnostic process, clinical signs such as bleeding on probing, development of periodontal pockets and gingival recessions, furcation involvement and presence of radiographic bone loss should be assessed prior to periodontal therapy, following active therapy, and during long-term supportive care. In addition, patient-reported outcomes such as increased tooth mobility, migration, and tilting should also be considered. More important to the patient, however, is the fact that assessment of signs of periodontal diseases must be followed by an appropriate treatment plan. Furthermore, it should be realized that clinical and radiographic periodontal diagnosis is based on signs which may not reflect the presence of active disease but rather represent the sequelae of a previous bacterial challenge. Hence, the aim of the present review is to provide a summary of clinical and radiographic diagnostic criteria required to classify patients with periodontal health or disease.

Sequential osseointegration of a novel implant system based on 3D printing in comparison with conventional titanium implants

OBJECTIVES

To evaluate the sequential osseointegration of a novel titanium implant system based on a 3D printing technology in comparison with conventional titanium implants.

MATERIAL AND METHODS

Two novel titanium implants based on 3D printing were tested in the mandible of eight Beagle dogs. As a control, two different commercially available titanium implants were used. The implants were staged to accommodate healing periods of 2 and 6 weeks. The primary outcome variable was bone-to-implant contact (BIC) in non-decalcified tissue sections and micro-CT analysis.

RESULTS

Histomorphometrically, the proportions of tissues adjacent to the implant surfaces were similar for all implants, whereas the BIC percentage of new mineralized bone was greater for the control implants after both 2 and 6 weeks (p < .05). Micro-CT analysis revealed increasing osseous volume and BIC from 2 to 6 weeks. In contrast to the histomorphometry, the BIC evaluation with the micro-CT data revealed a significantly higher BIC for the two test implants compared with controls (p < .001). The analysis of the total implant surface area disclosed a value that was approximately double as high for the test compared to the control implants.

CONCLUSIONS

The novel titanium implant system based on 3D printing yielded values for osseointegration that were adequate and satisfactory. The higher percentage of new mineralized bone in the control implants is explained by the fact of a completely different three-dimensional surface area.

Addition of Synthetic Biomaterials to Deproteinized Bovine Bone Mineral (DBBM) for Bone Augmentation-A Preclinical In Vivo Study

(1) Aim: To investigate the effect of synthetic bone substitutes, α-tricalcium phosphate (α-TCP) or bi-layered biphasic calcium-phosphate (BBCP) combined with deproteinized bovine bone mineral (DBBM), on bone formation. (2) Methods: Thirty critical size defects were randomly treated with the following five different treatment modalities: (1) negative control (NC, empty), (2) DBBM, (3) α-TCP + DBBM (1:1), (4) BBCP 3%HA/97%α-TCP + DBBM (1:1), and (5) BBCP 6%HA/94%α-TCP + DBBM (1:1). The samples, at four weeks post-surgery, were investigated by micro-CT and histological analysis. (3) Results: A similar level of new bone formation was demonstrated in the DBBM with α-TCP bone substitute groups when compared to the negative control by histomorphometry. DBBM alone showed significantly lower new bone area than the negative control (p = 0.0252). In contrast to DBBM, the micro-CT analysis revealed resorption of the α-TCP + DBBM, BBCP 3%HA/97%α-TCP + DBBM and BBCP 6%HA/94%α-TCP + DBBM, as evidenced by a decrease of material density (p = 0.0083, p = 0.0050 and p = 0.0191, respectively), without changing their volume. (4) Conclusions: New bone formation was evident in all defects augmented with biomaterials, proving the osteoconductive properties of the tested material combinations. There was little impact of the HA coating degree on α-TCP in bone augmentation potential and material resorption for four weeks when mixed with DBBM.

Oral health-related quality of life of patients rehabilitated with fixed and removable implant-supported dental prostheses

Dental implants have become a mainstream treatment approach in daily practice, and because of their high survival rates over time, they have become the preferred treatment option for prosthetic rehabilitation in many situations. Despite the relatively high predictability of implant therapy and high costs to patients, patient perceptions of success and patient-reported outcome measures have become increasingly significant in implant dentistry. Increasing numbers of publications deal with oral health-related quality of life and/or patient-reported outcome measures. The aim of this paper was to provide an overview of the available evidence on oral health-related quality of life of fully and partially dentate patients rehabilitated with fixed and removable implant-supported dental prostheses. A comprehensive electronic search was performed on publications in English up to 2021. A selection of standardized questionnaires and scales used for the evaluation of oral health-related quality of life were analyzed and explained. The analysis encompassed three aspects: a functional evaluation of oral health-related quality of life, an esthetic assessment of oral health-related quality of life, and a cost-related evaluation of oral health-related quality of life for rehabilitation with dental implants. The data demonstrated that the preoperative expectations of patients markedly affected the outcomes perceived by the patients. As expected, reconstructions supported by implants substantially improved the stability of conventional dentures and allowed improved function and patient satisfaction. However, from a patient's perspective, oral health-related quality of life was not significantly greater for dental implants compared with conventional tooth-supported prostheses. The connection of the implants to the prostheses with locators or balls indicated high oral health-related quality of life. The data also suggest that patient expectation is not a good predictor of treatment outcome. In terms of esthetic outcomes, the data clearly indicate that patients' perceptions and clinicians' assessments differed, with those of clinicians yielding higher standards. There were no significant differences found between the esthetic oral health-related quality of life ratings for soft tissue-level implants compared with those for bone-level implants. Comparison of all-ceramic and metal-ceramic restorations showed no significant differences in patients' perceptions in terms of esthetic outcomes. Depending on the choice of outcome measure and financial marginal value, supporting a conventional removable partial denture with implants is cost-effective when the patient is willing to invest more to achieve a higher oral health-related quality of life. In conclusion, the oral health-related quality of life of patients rehabilitated with implant-supported dental prostheses did not show overall superiority over conventional prosthetics. Clinicians' and patients' evaluations, especially of esthetic outcomes, are, in the majority of cases, incongruent. Nevertheless, patient-reported outcomes are important in the evaluation of function, esthetics, and the cost-effectiveness of treatment with implant-supported dental prostheses, and should be taken into consideration in daily practice.

No apparent association between dental implants and mandibular fractures resulting from external forces

OBJECTIVES

Dental implants are cylindrical metallic screws inserted into the jawbone to replace missing teeth. Their location may affect the pattern of fractures that occur as a result of the traumatic forces to the mandible. The aim of this study was to investigate possible influences of dental implants on the patterns of mandibular fractures triggered by external forces.

MATERIAL AND METHODS

In this observational cross-sectional study, a total of 390 patients with mandibular fractures diagnosed between February 2016 and December 2020 were examined and the presence or absence of dental implants in the fracture gap was noted. Clinical and radiological data were analyzed in relation to the fracture line, the dental status, and the location of any implants.

RESULTS

A total of 16 patients (4.1%) had previously placed dental implants in the mandible. Various fracture patterns were observed. Some yielded typical fracture lines located in the anatomically weak areas along the roots of the incisors, the mental foramina, and long-rooted molars. Occasionally, fracture lines were detected in combination with condylar fractures. Dental implants were not directly involved in any fracture line, except one. In that case, the fracture line extended from the alveolar process straight along the implant body, mimicking initial disintegration of the implant, with erosion of the surrounding bone.

CONCLUSIONS

Once dental implants have osseointegrated, mandibular fractures are rarely projected along the implant surface.

CLINICAL RELEVANCE

This observational retrospective cross-sectional study failed to associate mandibular fracture lines with the presence of dental implants.

Periodontal disease progression in the second half of life and following a single episode of scaling and root planing-A clinical study in the Sri Lankan tea plantation cohort with documented clinical parameters over more than 40 years

BACKGROUND

To evaluate periodontal disease progression (PDP) and potentially detectable effects of a single episode of scaling and root planing (se-SRP) in subjects lacking professional dental care and oral hygiene practices for >40 years.

METHODS

In 2013, se-SRP was offered to all available subjects from the original cohort of 480 males initially established in 1970. From a total of 75 attending the previous examination in 2010 (baseline), 27 consented to receive the intervention while 18 declined and served as controls. Clinical data were recorded again in 2014 (follow-up) similarly to the previous surveys (1970 to 2010).

RESULTS

Subjects' mean age in 2010 was 62.5 (± 3.6, test) and 61.9 (± 3.8, control) years. At follow-up, both groups presented with elevated tooth loss of 1.2 (from 15.5 ± 9.0, test) and 1.5 (from 17.9 ± 6.6, control) resulting in 1,392 (test) and 1,061 (control) sites available for further analysis. In both groups, clinical attachment level (CAL) loss and probing depths (PD) deteriorated. PD increase of 0.22 mm (± 1.70) in the test group was significantly higher compared with the control group (0.08 mm ± 1.30) (P <0.0001) demonstrating unaffected PDP. Computed estimates of further PDP revealed CAL and PD reductions in subjects aged ≥40 years. Specifically, the latter was positively correlated with tooth loss in subjects aged ≥40 years (P = 0.69, P = 0.0012) and ≥50 years (r = 0.62, P <0.0001).

CONCLUSION

se-SRP in previously untreated periodontitis subjects aged ≥50 years may be ineffective in reducing PDP thus demanding advanced preventive measures, treatment in the first half of life, and sustained access to supportive care.

Evaluation of the implant disease risk assessment (IDRA) tool: A retrospective study in patients with treated periodontitis and implant-supported fixed dental prostheses (FDPs)

Aim

To evaluate the Implant Disease Risk Assessment (IDRA) tool for the prediction of peri‐implantitis in treated periodontitis patients with implant‐supported fixed dental prostheses (FDPs) after at least 5 years of function.

Material and methods

From the patient pool of implant patients enrolled in a regular supportive periodontal therapy programme (SPT) for at least 5 years, 239 patients were screened. Eighty patients met the inclusion criteria and underwent evaluation through the criteria of the IDRA tool. Areas under the curve (AUCs) for receiver operating characteristic (ROC) curves including 95% confidence intervals were estimated.

Results

Seventy‐nine patients (43 males and 36 females, 8 smokers), aged on average 59.0 years (range: 40–79 years) at baseline (i.e. FDP delivery) were analysed. The calculated IDRA‐risk was in 34 patients (42.5%) a moderate risk, while 45 patients (56.3%) were considered at high IDRA‐risk. One patient categorized at low IDRA‐risk was excluded from the analysis.

The AUC was 0.613 (95% CI: 0.464–0.762) if the IDRA‐risk was associated with prevalence of peri‐implantitis at the most recent follow‐up. Peri‐implantitis was diagnosed in 4 patients (12%) at moderate and in 12 patients (27%) at high IDRA‐risk, respectively. The calculated odds ratio for developing peri‐implantitis in patients with high IDRA‐risk compared with patients with moderate IDRA‐risk was 2.727 with no statistically significant difference between the two groups (95% CI: 0.793–9.376).

Conclusion

Within the limitations of the present retrospective study, the IDRA algorithm might represent a promising tool to assess patients at moderate or high risk of developing peri‐implantitis.

Long-term clinical outcomes of periodontal regeneration with Enamel Matrix Derivative (EMD): a retrospective cohort study with a mean follow-up of 10 years

BACKGROUND

Despite the large body of evidence on the efficacy of Enamel Matrix Derivative (EMD) in the treatment of periodontal intrabony defects, few studies reported long-term data (≥ 10-year).

METHODS

Periodontal patients treated with regenerative surgery with EMD between 1999 and 2012 were invited to participate in a clinical examination. The following clinical parameters were recorded and compared at baseline (T0), 6 months after surgery (T1) and after at least 8 years of follow-up (T2): probing depth (PD), gingival recession (GR), clinical attachment level (CAL), plaque and bleeding scores. The primary outcome variable was CAL change.

RESULTS

Forty-one patients with 75 treated teeth were available for analysis. Out of these, 68 (tooth survival rate: 90.7%) reached the latest follow-up with a mean observation period of 10.3 years (range: 8.0-21.3). The most frequent reason for tooth loss was recurrence of periodontal disease. Tooth survival curves showed a statistically significant difference between smokers and non-smokers (p = 0.028). Mean CAL changed from 8.43 ± 1.86 (T0) to 6.47 ± 1.70 (T1) (p<0.001) and to 5.91 ± 1.83 (T2) (p<0.001). At T1, a CAL gain of ≥3 mm was measured in 35% of the defects while at T2 it was detected in 51% of cases.

CONCLUSIONS

Within their limitations, the present results have shown that in intrabony defects, the clinical improvements obtained following regenerative surgery with EMD can be maintained on a mean period of 10 years. Smoking status and maxillary molars were correlated with an increased risk for tooth and CAL loss, respectively. This article is protected by copyright. All rights reserved.

Collagen-Based Matrices for Osteoconduction: A Preclinical In Vivo Study

The aim of this study was to evaluate the influence of additional hydroxyapatite (HA) in collagen-based matrices (CM) and membrane placement on bone formation in calvarial defects. Critical size defects in the calvaria of 16 New Zealand White Rabbits were randomly treated with CM or mineralized collagen-based matrices (mCM). Half of the sites were covered with a collagen membrane. Animals were euthanized after 12 weeks of healing. The samples were studied by micro-CT and histology. Newly formed lamellar bone was observed in all samples at the periphery of the defect. In the central areas, however, new bone composed of both woven and lamellar bone was embedded in the soft tissue. Samples treated with mCM showed more residual biomaterial and induced more small bony islands in the central areas of the defects than samples with CM. Nevertheless, a complete defect closure was not observed in any of the samples at 12 weeks. Membrane placement resulted in a decrease in bone density and height. Significant differences between the groups were revealed only between CM groups with and without membrane coverage for bone height in the central area of the defect. Neither mineralization of CM nor membrane placement improved the osteogenic capacity in this particular defect. Nevertheless, mineralisation influenced bone density without a membrane placement and bone volume underneath a membrane. CM may be used as a scaffold in bone regeneration procedures, without the need of a membrane coverage. Further preclinical studies are warrant to optimise the potential of mCM.

The effect of synthetic bone graft substitutes on bone formation in rabbit calvarial defects

The aim of this study was to evaluate the influence of the intensity of the biomimetic hydroxyapatite (HA) coating of α-tricalcium phosphate (α-TCP) on biomaterial degradation and bone formation. Twenty-four female NZW rabbits of approximately 12 weeks of age were used. Critical size defects were randomly treated with 3%:97% HA:α-TCP (BBCP1), 12%:88% HA:α-TCP (BBCP2), and 23%:77% HA:α-TCP (BBCP3), respectively or sham. All defects were covered with a resorbable collagen membrane. Animals were euthanized after 3 and 12 weeks of healing and samples were investigated by micro-CT and histologic analysis. Ingrowth of newly formed woven bone from the original bone at 3-week healing period was observed in all samples. At the 12-week healing period, the new bone in the peripheral area was mainly lamellar and in the central region composed of both woven and lamellar bone. New bony tissue was found on the surface of all three types of granules and at the interior of the BBCP1 granules. Samples with 3% HA showed significantly less residual biomaterial in comparison to the other two groups. Furthermore, BBCP1 significantly promoted new bone area as compared to other three groups and more bone volume as compared to the control. Within its limitations, this study indicated the highest degradation rate in case of BBCP1 concomitant with the highest rate of bone formation. Hence, formation of new bone can be affected by the level of biomimetic HA coating of α-TCP.

Clinical Parameters and Oral Fluid Biomarkers in Gingivitis Subjects using an Electric Toothbrush with Irrigator vs a Manual Toothbrush Alone over 8 Weeks: A Randomised Controlled Clinical Trial

PURPOSE

To compare clinical outcomes and oral fluid biomarkers in gingivitis subjects using an electric toothbrush/irrigator combination (test) or a manual toothbrush alone (control) over 8 weeks.

MATERIALS AND METHODS

Subjects were randomly assigned to two groups of n = 30. In both groups, toothbrushing was performed twice daily at home and no additional interdental cleaning aids were allowed. Plaque Index (PLI), Gingival Index (GI), whole saliva (WS), and gingival crevicular fluid (GCF) samples were collected at weeks 2, 4, and 8.

RESULTS

Subjects' mean age was 23 years and 52% were female. Overall baseline means were 1.31 for PLI, 1.07 for GI, and 34.9 for number of bleeding sites. At every follow-up visit, both groups differed statistically significantly (p < 0.001) from baseline for all clinical parameters. The test group demonstrated statistically significantly (p < 0.001) greater reductions in GI vs the control group by 18% at week 2, 17% at week 4 and 24% at week 8. The test group also demonstrated statistically significantly (p < 0.002) greater reductions in the number of bleeding sites vs the control group by 33% at week 2, 34% at week 4 and 43% at week 8. Between-group comparisons for both WS and GCF revealed numerical trends for decreased levels of interleukin (IL)-1β in GCF after 4 and 8 weeks, but these were not statistically significant.

CONCLUSION

In subjects using the electric toothbrush/irrigator combination, increased clinical improvements may be found accompanied by similarly improved trends for oral fluid biomarkers such as IL-1β.

Efficacy of laser monotherapy or non-surgical mechanical instrumentation in the management of untreated periodontitis patients. A systematic review and meta-analysis

Objective

To evaluate and compare the effects of laser monotherapy with non-surgical mechanical instrumentation alone in untreated periodontitis patients.

Materials and methods

A focused question was formulated based on the Population, Intervention, Comparison, Outcome, and Study design criteria (PICOS): in patients with untreated periodontitis, does laser mono-therapy provide adjunctive effects on pocket probing depth (PPD) changes compared with non-surgical instrumentation alone? Both randomized controlled clinical trials (RCTs) and controlled clinical trials (CCTs) were included. The results of the meta-analyses are expressed as weighted mean differences (WMD) and reported according to the PRISMA guidelines.

Results

The search yielded 1268 records, out of which 8 articles could be included. With respect to PPD changes, a meta-analysis including 5 articles (n = 148) failed to identify statistically significant differences in favor of laser monotherapy for PPD change (WMD = 0.14 mm; 95% CI: − 0.04/0.32; z = 1.51; p = 0.132) nor for clinical attachment level (CAL) (WMD = 0.04 mm; 95% CI: − 0.35/0.42; z = 0.19; p = 0.850). Data on cost-effectiveness are lacking. One study reported patient-related outcome measures (PROMS).

Conclusions

In untreated periodontitis patients, laser monotherapy does not yield superior clinical benefits compared with non-surgical mechanical instrumentation alone.

Clinical relevance

In untreated periodontitis patients, mechanical instrumentation with hand and/or ultrasonic instruments remains the standard of care.

Oral Implants: The Paradigm Shift in Restorative Dentistry

The discovery of the phenomenon "osseointegration," or functional ankylosis, has led to the development of oral implants with high clinical performance. Consequently, the placement of titanium implants has changed the paradigms of restorative dentistry. Implants are used to prevent placing reconstructions anchored on natural teeth when these are vital and intact. Furthermore, implants are suitable to improve subjective chewing function and to replace missing and strategically important abutments. The osseointegration process is characterized by a predictable sequence of healing events that encompass the formation of woven bone, parallel fibers, and lamellar bone and result in fully functional bone that will remodel throughout life. While the osseointegration facilitates the use of implants as prosthetic abutments, it has to be kept in mind that the peri-implant soft tissue may be subject to biological complications. This, in turn, may result in an infectious process that will jeopardize the osseointegration. Consequently, the monitoring of the peri-implant tissues is an important aspect, and early intervention in situations with peri-implant mucositis is mandatory for the prevention of peri-implantitis. Hence, it is evident that oral implants need lifelong maintenance care if their longevity is to be assured.

Periodontal health and gingival diseases and conditions on an intact and a reduced periodontium: Consensus report of workgroup 1 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions

Periodontal health is defined by absence of clinically detectable inflammation. There is a biological level of immune surveillance that is consistent with clinical gingival health and homeostasis. Clinical gingival health may be found in a periodontium that is intact, i.e. without clinical attachment loss or bone loss, and on a reduced periodontium in either a non-periodontitis patient (e.g. in patients with some form of gingival recession or following crown lengthening surgery) or in a patient with a history of periodontitis who is currently periodontally stable. Clinical gingival health can be restored following treatment of gingivitis and periodontitis. However, the treated and stable periodontitis patient with current gingival health remains at increased risk of recurrent periodontitis, and accordingly, must be closely monitored. Two broad categories of gingival diseases include non-dental plaque biofilm-induced gingival diseases and dental plaque-induced gingivitis. Non-dental plaque biofilm-induced gingival diseases include a variety of conditions that are not caused by plaque and usually do not resolve following plaque removal. Such lesions may be manifestations of a systemic condition or may be localized to the oral cavity. Dental plaque-induced gingivitis has a variety of clinical signs and symptoms, and both local predisposing factors and systemic modifying factors can affect its extent, severity, and progression. Dental plaque-induced gingivitis may arise on an intact periodontium or on a reduced periodontium in either a non-periodontitis patient or in a currently stable "periodontitis patient" i.e. successfully treated, in whom clinical inflammation has been eliminated (or substantially reduced). A periodontitis patient with gingival inflammation remains a periodontitis patient (Figure 1), and comprehensive risk assessment and management are imperative to ensure early prevention and/or treatment of recurrent/progressive periodontitis. Precision dental medicine defines a patient-centered approach to care, and therefore, creates differences in the way in which a "case" of gingival health or gingivitis is defined for clinical practice as opposed to epidemiologically in population prevalence surveys. Thus, case definitions of gingival health and gingivitis are presented for both purposes. While gingival health and gingivitis have many clinical features, case definitions are primarily predicated on presence or absence of bleeding on probing. Here we classify gingival health and gingival diseases/conditions, along with a summary table of diagnostic features for defining health and gingivitis in various clinical situations.

Periodontal health

OBJECTIVES

To date there is a paucity of documentation regarding definitions of periodontal health. This review considers the histological and clinical determinants of periodontal health for both intact and reduced periodontium and seeks to propose appropriate definitions according to treatment outcomes.

IMPORTANCE

Defining periodontal health is can serve as a vital common reference point for assessing disease and determining meaningful treatment outcomes.

FINDINGS

The multifactorial nature of periodontitis is accepted, and it is recognized that restoration of periodontal health will be defined by an individual's response to treatment, taking into account allostatic conditions.

CONCLUSIONS

It is proposed that there are 4 levels of periodontal health, depending on the state of the periodontium (structurally and clinically sound or reduced) and the relative treatment outcomes: (1) pristine periodontal health, with a structurally sound and uninflamed periodontium; (2) well-maintained clinical periodontal health, with a structurally and clinically sound (intact) periodontium; (3) periodontal disease stability, with a reduced periodontium, and (4) periodontal disease remission/control, with a reduced periodontium.

Excessive occlusal load on chemically modified and moderately rough titanium implants restored with cantilever reconstructions. An experimental study in dogs

OBJECTIVE

To evaluate the outcomes of excessively loaded implants.

MATERIAL AND METHODS

In five dogs, all mandibular premolars were extracted. After 3 months, six implants (three SLA® and three SLActive®) were placed (S). After 4 weeks, implants were restored: one single crown with stable occlusal contacts (SC), one crown and a cantilever unit with excessive occlusal contacts (OL), and a non-loaded implant (NL). Bleeding-on-probing (BoP), attachment level (AL), mucosal margin (GM) were assessed. Resonance frequency analysis (RFA) was assessed weekly. Standardized X-rays were taken at S, 4 and 24 weeks.

RESULTS

Similar findings were observed for SLA® and SLActive® implants regarding PlI, GI, GM, AL, and BL. No significant differences were detected between baseline and 24-weeks or between treatment modalities for all clinical parameters (p > .05). Six months after loading, RFA values were significantly greater than at implant placement. No significant differences between treatment modalities were found. Linear radiographic measurements yielded similar results between SLA® and SLActive® implants. SLA® OL implants yielded a statistically significant gain on peri-implant bone density over all other groups (p = .012). Radiographic results were confirmed by descriptive histology. Technically, loosened occlusal screws occurred in 13.3% (SC = 3.3%; OL = 10%), while abutment fractures totalized 23.3% (SC = 6.6%; OL = 16.6%).

CONCLUSIONS

Excessive occlusal load applied to implants (SLA® or SLActive®) restored with cantilevers did not cause loss of osseointegration or significant changes in their clinical, radiographic, or histologic outcomes. Early excessive occlusal load on SLA® implants promoted a gain in peri-implant bone density. Excessively loaded implants showed more technical complications.

Single-staged implant placement using the bone ring technique with and without membrane placement: Micro-CT analysis in a preclinical in vivo study

OBJECTIVES

To assess the impact of collagen membrane application on bone formation surrounding implants placed simultaneously with the bone ring technique.

MATERIAL AND METHODS

Dental implants were inserted simultaneously with the bone ring technique in standardized, vertical alveolar bony defects in the mandible of dogs. On one side of the mandible, the augmented sites were covered with a collagen membrane (M-Group). On the contralateral side, no membranes were used (NM-Group). Implants were left to heal with osseointegration for three and six months. The harvested samples were analyzed by means of micro-CT.

RESULTS

A nonparametric analysis of data revealed that the membranes were not a significant negative factor for bone volume (BV), but for bone-to-implant contact (BIC, p = .04). Absence of healing caps impaired BV (p = .04) and BIC (p = .02) as well. Furthermore, loss of healing caps and exposure to the oral environment significantly and negatively affected BV (p < .001) and bone mineral density (p < .05) within 2 mm below the implant shoulder. Implant exposure and healing time had a negative interaction effect on both BV (p = .01) and BIC (p = .01).

CONCLUSIONS

Within its limitations, the present study revealed no benefit of membrane application to implant placement simultaneous with the bone ring technique. Disruption of soft tissue healing was identified as a risk factor for decrease in BV and BIC.

Biological and mechanical complications of angulated abutments connected to fixed dental prostheses: A systematic review with meta-analysis

OBJECTIVES

To evaluate the biological and mechanical complications of angulated abutments on full-arch and partial jaw rehabilitations with a follow-up for at least 1 year.

METHODS

Electronic search was carried out in MEDLINE, EMBASE and Web of Science. Studies published between January 2000 and January 2019 were included. The quality of the included studies was assessed. The data extraction was focused on implant loss, marginal bone loss and mechanical complications, and meta-analyses were performed for marginal bone loss, mechanical complications and implant failure.

RESULTS

Nine studies, three prospective and six retrospective cohort studies were included. They reported on 797 patients that received 4127 implants. The total number of abutments was 4079 of which 1673 were angulated, and 2406 were straight. All abutments were prefabricated. Angulated abutments were associated with increased implant failure rates (two studies; RR = 7.30; 95% CI = 2.79-19.08) and an effect that was both statistically significant (P < .001) and clinically relevant. Three studies reported differentiated data for mechanical and technical complications at 1 year of follow-up, being mostly related to the retention screw while screw fracture. Angulated abutments were associated with a statistically significant increase in MBL 1 year after insertion compared to straight abutments (three studies; MD = 0.08 mm; 95% CI = 0.01-0.14 mm; P = .02), which might be, however, clinically negligible.

CONCLUSIONS

The prosthetic complications such as screw loosening and abutment loosening were frequent. After 1 year of follow-up, implants supporting angulated abutments yielded significantly more marginal bone loss than those supporting straight abutments.

Tomographic evaluation of the influence of the placement of a collagen membrane subjacent to the sinus mucosa during maxillary sinus floor augmentation: a randomized clinical trial

Aim

To study the influence of a collagen membrane placed subjacent to the sinus mucosa on the dimensional changes of augmented maxillary sinus floor.

Methods

Twenty patients were recruited in the study and randomly assigned to two groups. After the elevation of the maxillary sinus mucosa, a collagen membrane with standardized dimensions was placed at the test sites subjacent to the sinus mucosa and the elevated space was filled with a xenograft, both at test and control sites. A collagen membrane was then used to cover the antrostomy at both sites, and sutures were applied to close the wounds. Cone beam computed tomographies (CBCTs) were taken for all patients before surgery (T0), after 1 week from sinus floor augmentation (T1), and after 9 months of healing (T2). Dimensional changes over time of soft and hard tissues were evaluated on the CBCTs.

Results

After 1 week of healing, the sinus floor was elevated by 10.0 ± 2.8 mm and 10.6 ± 2.5 mm at the no-membrane and membrane groups, respectively. After 9 months of healing, a similar reduction of the height was observed in both groups, providing a total vertical augmentation of 8.6 ± 2.8 mm at the no-membrane sites and 9.1 ± 3.1 mm at the membrane sites. After 9 months of healing, the hard tissues subjacent to the sinus mucosa appeared to be partially corticalized in three patients in the no-membrane group and in six patients in the membrane group.

Conclusions

The use of collagen membranes subjacent to the sinus mucosa did not influence the dimensional variations of the augmented regions and the clinical outcomes after 9 months of healing also in absence of perforations.

Biological factors involved in alveolar bone regeneration: Consensus report of Working Group 1 of the 15th European Workshop on Periodontology on Bone Regeneration

BACKGROUND AND AIMS

To describe the biology of alveolar bone regeneration.

MATERIAL AND METHODS

Four comprehensive reviews were performed on (a) mesenchymal cells and differentiation factors leading to bone formation; (b) the critical interplay between bone resorbing and formative cells; (c) the role of osteoimmunology in the formation and maintenance of alveolar bone; and (d) the self-regenerative capacity following bone injury or tooth extraction were prepared prior to the workshop.

RESULTS AND CONCLUSIONS

This summary information adds to the fuller understanding of the alveolar bone regenerative response with implications to reconstructive procedures for patient oral rehabilitation. The group collectively formulated and addressed critical questions based on each of the reviews in this consensus report to advance the field. The report concludes with identified areas of future research.

Intra-oral single-site comparisons of periodontal and peri-implant microbiota in health and disease

OBJECTIVE

Periodontitis and peri-implantitis are oral infectious-inflammatory diseases that share similarities in their pathology and etiology. Our objective was to characterize the single-site subgingival and submucosal microbiomes of implant-rehabilitated, partially dentate Chinese subjects (n = 18) presenting with both periodontitis and peri-implantitis.

MATERIALS AND METHODS

Subgingival/submucosal plaque samples were collected from four clinically distinct sites in each subject: peri-implantitis submucosa (DI), periodontal pocket (DT), clinically healthy (unaffected) peri-implant submucosa (HI), and clinically healthy (unaffected) subgingival sulcus (HT). The bacterial microbiota present was analyzed using Illumina MiSeq sequencing.

RESULTS

Twenty-six phyla and 5,726 operational taxonomic units (OTUs, 97% sequence similarity cutoff) were identified. Firmicutes, Proteobacteria, Fusobacteria, Bacteroidetes, Actinobacteria, Synergistetes, TM7, and Spirochaetes comprised 99.6% of the total reads detected. Bacterial communities within the DI, DT, HI, and HT sites shared high levels of taxonomic similarity. Thirty-one "core species" were present in >90% sites, with Streptococcus infantis/mitis/oralis (HMT-070/HMT-071/HMT-638/HMT-677) and Fusobacterium sp. HMT-203/HMT-698 being particularly prevalent and abundant. Beta-diversity analyses (PERMANOVA test, weighted UniFrac) revealed the largest variance in the microbiota was at the subject level (46%), followed by periodontal health status (4%). Differing sets of OTUs were associated with periodontitis and peri-implantitis sites, respectively. This included putative "periodontopathogens," such as Prevotella, Porphyromonas, Tannerella, Bacteroidetes [G-5], and Treponema spp. Interaction network analysis identified several putative patterns underlying dysbiosis in periodontitis/peri-implantitis sites.

CONCLUSIONS

Species (OTU) composition of the periodontal and peri-implant microbiota varied widely between subjects. The inter-subject variations in subgingival/submucosal microbiome composition outweighed differences observed between implant vs. tooth sites, or between diseased vs. healthy (unaffected) peri-implant/periodontal sites.

Nonsurgical therapy for teeth and implants-When and why?

As periodontal and peri-implant diseases represent opportunistic infections, antiinfective therapy is the method of choice. Correctly performed, the treatment outcomes will include resolution of the inflammation concomitant with shrinkage of the tissues, reflected in reduced probing depths. Depending on the patient data obtained after initial antiinfective therapy, further - mostly surgical - treatment may be rendered to reach the goals of a healthy periodontium and peri-implant tissues. Patient compliance is as important as operator skills for optimal treatment outcomes. Regenerative therapy may be applied in compliant patients and for appropriate defects. This article depicts the historical development of periodontal therapy during the 20th century and addresses the various outcome parameters to be used in daily decision making. Obviously, nonsurgical therapy has gained clinical relevance, resulting in highly satisfactory treatment outcomes in many cases. The critical probing depth above which positive attachment gain is registered varies from one treatment modality to another. It is a concept that helps facilitate decision making for additional therapeutic measures after initial therapy. Treatment of peri-implant mucositis prevents development of peri-implantitis. Hence, nonsurgical treatment of mucositis is frequently performed during the continuous monitoring of oral implants. This chapter of Periodontology 2000 presents evidence for the prevention and therapy of peri-implant diseases.

Reconstructive aspects: Summary and consensus statements of group 3. The 5th EAO Consensus Conference 2018

OBJECTIVES

The tasks of this working group were to evaluate the existing evidence on the efficiency and efficacy of the digital and conventional workflows for the fabrication of fixed implant reconstructions, to assess the performance of all-ceramic fixed implant reconstructions and, finally, to evaluate the outcomes of internally and externally connected implant abutments and reconstructions.

METHODS

Four reviews were available analyzing the current literature on the respective topics. One review dealt with the efficiency and efficacy of digital and conventional fabrication workflows. Two reviews analyzed the outcomes of all-ceramic fixed implant reconstructions, one focusing on single-implant reconstructions and the other evaluating multiple-unit implant fixed dental prostheses (FDPs). The fourth review evaluated the clinical outcome on external, respectively, internal implant-abutment connections. These reviews were the basis for the discussions within the group and at the plenary sessions.

RESULTS

The present consensus report gives the consensus statements, the clinical recommendations, and the implications for future research as discussed and approved by the plenum of the consensus conference. The four manuscripts by Mühlemann et al., Rabel et al., Pieralli et al., and Pjetursson et al. are published as part of the journal supplement of the present EAO consensus conference.

Time between recall visits and residual probing depths predict long-term stability in patients enrolled in supportive periodontal therapy

AIM

To relate the time between recall visits and residual periodontal probing depths (PPDs) to periodontal stability in patients enrolled in supportive periodontal therapy (SPT).

MATERIALS AND METHODS

Retrospective data on residual PPDs from 11,842 SPT visits were evaluated in SPT patients at the Medi School of Dental Hygiene (MSDH), Bern, Switzerland, 1985-2011. A residual PPD-based algorithm was developed to compute SPT intervals with no expected change of residual PPD.

RESULTS

A total of 883 patients aged 43.9 (±13.0) years and 55.4% (n = 489) being females were identified. Linear mixed model analysis yielded highest statistically significant impact on PPD change with time between SPT visits, presence of residual PPD ≥4 mm, and bleeding on probing (p < 0.0001). Patients returning for SPT five times consecutively earlier than computed presented mean % PPDs ≥4 mm of 5.8% (±3.9) compared with patients returning later (19.2%, ±7.6) (p < 0.0001). Additionally, patients attending >50% of their SPT visits earlier versus later demonstrated increased periodontal stability after 5 years (p = 0.0002) and a reduced frequency of tooth loss (0.60, ±0.93 versus 1.45, ±2.07) after 20 years (p < 0.0001).

CONCLUSIONS

To reach and maintain periodontal stability during SPT, individual quantitative data from comprehensive residual PPD profiles may contribute to the improved planning of SPT intervals.

Long-term follow-up of single crowns supported by short, moderately rough implants-A prospective 10-year cohort study

OBJECTIVES

To evaluate prospectively the clinical and radiographic outcomes after ten years of short (6 mm) implants with a moderately rough surface supporting single crowns in the posterior region.

MATERIAL AND METHODS

Forty 6 mm modified sandblasted large-grit acid-etched (mod-SLA), soft tissue level implants were installed in the distal segments of 35 consecutive patients. After 6 weeks of healing, abutments were tightened, and single porcelain-fused-to-metal crowns were cemented. Implant survival, marginal bone loss, and clinical crown/implant ratio were evaluated at various time intervals up to 10 years after loading.

RESULTS

Two out of the 40 implants were lost before loading, one implant was lost after 7 years because of peri-implantitis. One patient with two implants died and was excluded from analysis. Two patients did not come at the 10-year follow-up and were considered as drop out (2 implants). The survival rate was 91.7% (n = 36). Thirty-three implants were available for marginal bone loss evaluation. A mean marginal bone loss after 10 years of function was 0.8 ± 0.7 mm. Between 5 and 10 years, the loss was 0.2 ± 0.4 mm. No technical complications were registered during the 10-year period. The clinical crown/implant ratio increased with time from 1.6 at the delivery of the prosthesis to 2.0 after 10 years of loading with no increase between 5 and 10 years.

CONCLUSION

Short (6 mm) implants with a moderately rough surface supporting single crowns in the posterior region and loaded after 6-7 weeks maintained full function for at least 10 years with low marginal bone resorption.

Influence of the height of the antrostomy in sinus floor elevation assessed by cone beam computed tomography- a randomized clinical trial

PURPOSE

To evaluate the influence of the height of the antrostomy on dimensional variations of the elevated space after sinus floor elevation.

MATERIALS AND METHODS

Twenty-four healthy volunteers planned for sinus floor elevation were included in the study. An antrostomy of either 4 mm (Group A) or 8 mm (Group B) in height was prepared in the lateral wall of the sinus. Cone beam computed tomography (CBCT) scans were taken before surgery (T0) and after 1 week (T1) and 9 months (T2). Dimensional variation analyses were performed.

RESULTS

The CBCT scans of 10 patients per group were evaluated. After 1 week (T1), the sinus floor was found elevated in the middle region by 12.0 ± 2.3 mm in Group A, while in Group B, the height was 11.8 ± 2.1 mm. After 9 months (T2), the respective heights were 9.9 ± 2.4 mm and 8.9 ± 2.7 mm, with a reduction of -2.1 ± 2.2 mm in Group A and -3.0 ± 2.6 mm in Group B. The area in a central position was reduced by 25.5% to 34.2%, showing a slightly higher shrinkage in Group B compared with Group A. However, no statistically significant differences were found between the two groups.

DISCUSSION

In maxillary sinus floor elevations performed by the lateral approach, the size of the antrostomy did not affect the clinical and radiographic outcomes.

How do visual-spatial and psychomotor abilities influence clinical performance in periodontal plastic surgery?

AIM

We want to evaluate the relationship of self-assessed experience and proficiency, manual dexterity and visual-spatial ability with surgical performance.

MATERIAL AND METHODS

A total of 26 professionals were included in the study which consisted of four parts: (a) self-assessment by a questionnaire regarding proficiency and experience, (b) evaluation of visual-spatial ability, (c) testing of manual dexterity assessed by validated psychomotor tests and (d) evaluation of surgical performance by Objective Structured Assessment of Technical Skills (OSATS).

RESULTS

Self-assessed proficiency and experience levels did not correlate with objectively evaluated surgical performances (OSATS). However, low-level visual-spatial ability tests strongly correlated with OSATS while intermediate- and high-level tests did not. No correlation was found between psychomotor ability and clinical performance.

CONCLUSIONS

Self-assessed proficiency is not a good predictor for surgical performance as experts tend to be overconfident. To evaluate and predict surgical performance, visual-spatial ability tests seem to be more appropriate than measuring manual dexterity which failed to correlate with the surgical outcome.

Histological and micro-computed tomography evaluations of newly formed bone after maxillary sinus augmentation using a xenograft with similar density and mineral content of bone: An experimental study in rabbits

The objective of this study was to evaluate possible differences in the assessment of bone formation between histological and micro-computed tomography (CT) analyses in maxillary sinuses augmented with a xenograft with similar density and mineral content of bone. A collagen membrane was placed subjacent the elevated sinus mucosa at the test sites of 18 rabbits, and the elevated spaces were filled with xenograft. The antrostomy was covered with collagen membranes, bilaterally. Six rabbits per group were sacrificed after 2, 4, and 8 weeks of healing. Biopsies were retrieved and scanned in a high-resolution micro-CT at two different gray thresholds. Histological assessments were subsequently performed. At the histological analyses, bone increased over time, from 7.5 ± 2.4% to 27.0 ± 5.3%, between 2 and 8 weeks of healing. The highest content of bone was found close to the sinus bone walls, whereas the middle regions contained lower amounts. At the micro-CT analyses, discrepancies were found in bone content percentages compared with the histological analyses, especially after 2 weeks of healing and within the middle regions of the sinus, in which new bone was ~15-22% at the micro-CT analyses and only 1.6% at the histological evaluation. The outcomes of a micro-CT analysis performed in an early phase of healing may be altered when a resorbable bone substitute with similar density and mineral content of bone is applied.

Recombinant human BMP9 (RhBMP9) in comparison with rhBMP2 for ridge augmentation following tooth extraction: An experimental study in the Beagle dog

OBJECTIVES

The purpose of this study was to compare the effects of rhBMP2 with rhBMP9 on ridge augmentation following healing of extraction sockets in dogs.

MATERIAL AND METHODS

Five male Beagle dogs, approximately 12 months of age, were used. The mesial roots of the four maxillary premolars were endodontically treated. The distal roots were extracted, and the buccal bony walls removed. All extraction sockets were filled with deproteinized bovine bone mineral (DBBM). A collagen membrane was soaked with 4 μg or 20 μg of rhBMP9, 20 μg of rhBMP2 or sterile saline and placed over the augmented sites. All animals were euthanized after 8 weeks of healing and investigated by micro-CT and histologic analysis. A one-way ANOVA with Tukey's HSD post hoc test was used to compare the differences between the four groups.

RESULTS

New bone apposition in all defects was observed from the original bone. RhBMP samples showed an increase in bone formation in the buccal area and better integration of DBBM particles when compared to control sites. Both rhBMP9 defects showed higher values of bone (p = 0.024), bone marrow (p = 0.044), and total augmentation volume (p = 0.033) than the rhBMP2 (20 μg) or control sites. Highest bone area was found in rhBMP9 defects (p = 0.895).

CONCLUSIONS

Within the limitations of the present study, rhBMP9 sites demonstrated higher bone-inducing potential in combination with DBBM than rhBMP2. While rhBMP9s failed to demonstrate a clear dose-response relationship to the outcomes, future studies are necessary to evaluate the appropriate dose and carrier systems.

Biological and technical complications of tilted implants in comparison with straight implants supporting fixed dental prostheses. A systematic review and meta-analysis

OBJECTIVES

To evaluate the implant failure, marginal bone loss (MBL), and other biological or technical complications of restorations supported by tilted and straight implants after at least 3 years in function.

METHODS

Electronic and manual searches were performed in MEDLINE, Embase, Web of Science, and OpenGrey to identify clinical studies published up to December 2017. After duplicate study selection and data extraction, the risk of bias was assessed with the ROBINS-I tool. Random-effects meta-analyses of relative risks (RRs) or mean differences (MD) and their 95% confidence intervals (CIs) were performed, followed by subgroup/sensitivity analyses and application of the GRADE approach.

RESULTS

A total of 17 nonrandomized studies (eight prospective/nine retrospective) were included. The number of implants of the overall systematic review was 7,568 implants placed in 1,849 patients supporting either full-arch or partial implant prostheses. No difference in the failure of tilted and straight implants was seen (eight studies; 4,436 implants; RR = 0.95; 95% CI = 0.70 to 1.28; p = 0.74), with the quality of evidence being very low due to bias and imprecision. Likewise, no difference in MBL was seen between tilted and straight implants (16 studies; 5,293 implants; MD = 0.03 mm; 95% CI = -0.03 to 0.10 mm; p = 0.32), with the quality of evidence being very low due to bias and inconsistency. Contradictory results regarding implant survival were found from prospective and retrospective studies, which could indicate bias from the latter.

CONCLUSIONS

Within the limitations of the present systematic review, no effect of implant inclination on implant survival or peri-implant bone loss was found.

Influence of the position of the antrostomy in sinus floor elevation assessed with cone-beam computed tomography: A randomized clinical trial

AIM

The aim of the present study was to evaluate dimensional variations of augmented sinus volumes after sinus floor elevation using a lateral approach placing the antrostomy close to the sinus floor or more cranially to it.

METHODS

Twenty-four healthy volunteers in need of sinus floor elevation were included in the study. The lateral approach was adopted placing the antrostomy randomly either close to the level of the sinus floor (group A) or approximately 3-4 mm cranially (group B). Cone-beam computed tomography (CBCT) was done before surgery (T0) and after 1 week (T1) and 9 months (T2), and analyses on dimensional variations were performed.

RESULTS

CBCT of 10 patients per group were analyzed. At T1, the sinus floor was found to be elevated by 9.8 ± 2.1 mm in group A and 10.9 ± 1.9 mm in group B. At T2, shrinkage of 2.0 ± 1.7 mm in group A and 1.4 ± 2.5 mm in group B was observed. The area was reduced approximately 18-24% between T1 and T2. The sinus mucosa width increased by 4.3-5 mm between T0 and T1, and regained the original dimensions at T2.

CONCLUSIONS

The more cranial the antrostomy, the greater the augmentation height after 9 months.

Immediate loading at single crowns and 2-unit bridges supported by implants installed in a healed alveolar bony ridge or immediately after tooth extraction. An experimental study in dogs

To evaluate presumptive differences in osseointegration at implants installed in healed sites or extraction sockets, supporting either crowns or bridges that were functionally loaded or left unloaded. In six dogs, the mesial roots of the first mandibular molars were treated endodontically. Bilaterally, the teeth were hemisected, and the distal roots extracted. First and second mandibular premolars were extracted as well. After 3 months, the mandibular third and fourth distal roots were extracted after endodontic treatment of the mesial roots. Four implants were installed bilaterally, two in the healed sites corresponding to the second premolar and first molar regions, and two into the extraction sockets. Cobalt-chrome single crowns were prepared and installed in the two most anterior implants, and bridges at the two most posterior implants, bilaterally. A 3-unit bridge was applied to the premolars in the upper jaw only at the loaded sites. All prostheses had a flat occlusal surface and contacts in centric occlusion only at the loaded sites. Three months later, biopsies were retrieved for histological analysis. Higher levels of osseointegration and bone density were observed at the unloaded sites, both at implants installed in healed and post-extraction sites. However, only at implants installed in the post-extraction sites and supporting single crowns, the difference in bone-to-Implant contact was statistically significant. In implant installation immediately following extraction or delayed after three months, osseointegration and bone density were not affected by occlusal contact schemes.

Reposition of the bone plate over the antrostomy in maxillary sinus augmentation: A histomorphometric study in rabbits

OBJECTIVE

To test if repositioning the bony plate secured with a cyanoacrylate over the antrostomy in maxillary sinus augmentation was superior to covering the antrostomy with a collagen membrane in terms of the bone augmentation area and the bone density.

MATERIAL AND METHODS

After the exposure of the nasal bone in eighteen rabbits, a rectangular access window was prepared with a sonic instrument, and the bony plate was removed. A bilateral sinus mucosa elevation was performed, and the space was filled with a resorbable xenograft. On the test side, the bone plate was repositioned over the antrostomy and fixed with a cyanoacrylate. On the control side, a collagen membrane was placed over the opening. Per group, six animals were sacrificed after 2, 4, and 8 weeks of healing, respectively. Histological ground sections were prepared.

RESULTS

The augmented area after elevation decreased between 2 and 8 weeks from 9.4 ± 1.8 to 4.8 ± 2.8 mm² at the test and from 9.5 ± 2.6 and 5.1 ± 1.6 mm² at the control sites. Small amounts of new bone were seen after 2 weeks in both groups (~1.6%-2.5%) forming from the bony sinus walls. New bone density increased over time in both groups reaching ~ 10%-11% and ~ 23%-25% after 4 and 8 weeks, respectively. No statistically significant differences were found. Small residual defects were present both at the test sites in the margin of the bone plate, and at the control sites in the center of the antrostomy.

CONCLUSIONS

The bone healing in the elevated sinus space was similar irrespective of the coverage of the antrostomy. After 8 weeks, the bone plate repositioned on the antrostomy was incorporated while at the control sites the healing was still incomplete. Residual defects were still present in both groups.

Immediate and delayed loading of fixed dental prostheses supported by single or two splinted implants: A histomorphometric study in dogs

To evaluate presumptive differences in osseointegration at implants supporting crowns that are physiologically loaded either immediately or 3 months after installation. All premolars and first molars were extracted bilaterally in six dogs. After 3 months of healing, three implants were installed on the premolar region and two in the molar region in one side of the mandible. Likewise, after another 3 months, five implants were installed in the contralateral side, and impressions were taken bilaterally. Within 48 hours, two single crowns were screwed bilaterally onto two implants in the premolar region, and two splinted crowns reproducing the shape of the first molar were screwed bilaterally onto the implants in the molar region. The mesial implants were used as no-loaded controls. Sacrifices were performed after 3 months, and histological analyses were performed. At the premolar sites, mineralised bone-to-implant contact (MBIC%) was 78.0 ± 4.0% and 70.9 ± 7.9% at the delayed and immediately loaded sites, respectively. This difference was statistically significant. At the control implants, MBIC% was 61.4 ± 14.7% and 63.1 ± 13.1% at the delayed and the immediately loaded sites, respectively. At the molar sites, MBIC% was 79.2 ± 10.9% and 61.1 ± 10.3% at the delayed and immediately loaded sites, respectively. Applying a delayed loading to fixed dental prostheses supported by single or two splinted implants yielded higher proportions of bone-to-implant contact (osseointegration) compared to immediately loaded implants. Moreover, both types of loading protocols yielded a higher rate of osseointegration compared to unloaded implant sites after 3 months following implant installation.