The adjunctive effect of polydeoxyribonucleotide on bone formation in alveolar ridge preservation: A pre-clinical in vivo study.

AIM: This study investigated the adjunctive effect of polydeoxyribonucleotide (PDRN) on bone formation in alveolar ridge preservation (ARP) sockets. MATERIALS AND METHODS: Both mandibular second, third and fourth premolars of eight beagle dogs were randomly divided into ARP and ARP/PDRN groups. Following tooth extraction, ARP procedures were conducted using collagenized alloplastic graft material and bilayer collagen membrane soaked with normal saline (ARP group) or PDRN (ARP/PDRN group) for 10 min before application. Both groups were also randomly allocated to 2-, 4- or 12-week healing subgroups. The primary endpoint of this study was to compare histomorphometric differences between ARP and ARP/PDRN. The secondary endpoints of this study were to compare micro-CT analysis and three-dimensional volumetric measurement between the two groups. RESULTS: In the histomorphometric analysis, the ARP/PDRN group exhibited greater new bone formation at coronal, middle and total position compared with the ARP group at 2-week healing. The number of newly formed blood vessels was higher in the ARP/PDRN group than in the ARP group at 2- and 4-week healing. In micro-CT analysis, the mean new bone volume/total bone volume between ARP and ARP/PDRN was statistically significant at 2-week healing. Ridge volume alterations were significantly decreased in the ARP/PDRN group during entire healing time compared with the ARP group, especially on the buccal side. CONCLUSIONS: The application of PDRN in ARP might provide additional benefits for early bone regeneration and maintenance of buccal ridge volume.

Complications and treatment errors in peri-implant hard tissue management.

Bone augmentation procedures aim to regenerate the deficient alveolar ridge to properly place dental implants that are completely surrounded by bone. However, these are invasive and technically demanding surgeries that are not free of either complications or treatment errors. Careful patient selection and preparation is a mandatory process to reduce the rate of complications in bone regeneration procedures, irrespective of the technique used. It is important to assess the cost benefit of the intervention and to evaluate the potential impact on the patient's quality of life, especially in the elderly and medically compromised patients. Most common postoperative complications are wound dehiscences, which may be reduced, at least partially, by proper knowledge of the surgical technique and the craniofacial anatomy. Other complications that may appear are postoperative infections or nerve injuries. The aim of this narrative review is to summarize the best available scientific evidence on the incidence of complications, as well as the ideal strategies for their prevention and management. Depending on the severity of the complication, treatment approaches may vary and can include drug prescription or even surgical re-entries to remove exposed barrier membranes or contaminated bone grafts. Adequate prevention and proper management of complications associated with bone augmentation interventions are a requirement for clinicians carrying out these demanding procedures. A series of cases illustrating proper management of complications in different clinical scenarios is presented.

Techniques on vertical ridge augmentation: Indications and effectiveness.

Vertical ridge augmentation techniques have been advocated to enable restoring function and esthetics by means of implant-supported rehabilitation. There are three major modalities. The first is guided bone regeneration, based on the principle of compartmentalization by means of using a barrier membrane, which has been demonstrated to be technically demanding with regard to soft tissue management. This requisite is also applicable in the case of the second modality of bone block grafts. Nonetheless, space creation and maintenance are provided by the solid nature of the graft. The third modality of distraction osteogenesis is also a valid and faster approach. Nonetheless, owing to this technique's inherent shortcomings, this method is currently deprecated. The purpose of this review is to shed light on the state-of-the-art of the different modalities described for vertical ridge augmentation, including the indications, the step-by-step approach, and the effectiveness.

Guided bone regeneration in implant dentistry: Basic principle, progress over 35 years, and recent research activities.

Bone augmentation procedures are frequent today in implant patients, since an implant should be circumferentially anchored in bone at completion of bone healing to have a good long-term stability. The best documented surgical technique to achieve this goal is guided bone regeneration (GBR) utilizing barrier membranes in combination with bone fillers. This clinical review paper reflects 35 years of development and progress with GBR. In the 1990s, GBR was developed by defining the indications for GBR, examining various barrier membranes, bone grafts, and bone substitutes. Complications were identified and reduced by modifications of the surgical technique. Today, the selection criteria for various surgical approaches are much better understood, in particular, in post-extraction implant placement. In the majority of patients, biodegradable collagen membranes are used, mainly for horizontal bone augmentation, whereas bioinert PTFE membranes are preferred for vertical ridge augmentation. The leading surgeons are using a composite graft with autogenous bone chips to accelerate bone formation, in combination with a low-substitution bone filer to better maintain the augmented bone volume over time. In addition, major efforts have been made since the millenium change to reduce surgical trauma and patient morbidity as much as possible. At the end, some open questions related to GBR are discussed.

Minimal invasiveness in vertical ridge augmentation.

Vertical ridge augmentation is one of the most challenging procedures in implant dentistry because of the advanced skills required by the operator and the fact that bone augmentation is aimed outside the bony contour, in an environment of reduced blood supply. What is more, the flap management required to ensure soft tissue closure frequently leads to associated comorbidities in terms of swelling and hematomas. For these reasons, and even if autologous onlay block grafts are still the gold standard, new techniques and biomaterials have favored the development of potentially less invasive approaches. The present work evaluates the most recent strategies in vertical ridge augmentation to reduce invasiveness and complications, including diagnostic/treatment planning considerations, surgical techniques, digital tools (eg, customized titanium meshes/membranes or bone blocks), and future trends in the field of tissue engineering and cell therapy.

Facial implant gingival level and thickness changes following maxillary anterior immediate tooth replacement with scarf-connective tissue graft: A 4-13-year retrospective study.

OBJECTIVE: A scarf-shaped connective tissue graft can be placed at the facial and proximal aspect of the peri-implant soft tissue zone during immediate implant placement and provisionalization (IIPP) procedures in the esthetic zone to optimize implant esthetics without the need of flap reflection. This retrospective study evaluated soft tissue stability after scarf-connective tissue graft (S-CTG) in conjunction with IIPP procedures in the esthetic zone. MATERIALS AND METHODS: Patients who received IIPP with S-CTG with a minimum 1-year follow-up were evaluated. Mid-facial gingival level (MFGL) change and mid-facial gingival thickness (MFGT) change were measured and compared at the pre-op (T0), IIPP + S-CTG surgery (T1), follow up appointment with MFGT measurement (T2), and latest follow-up appointment (T3). Implant success rate and graft necrosis were also recorded. RESULTS: A total of 22 IIPP and S-CTG procedures in 20 patients were evaluated in the study. After a mean follow-up of 8.2 years (3.9-13.4) (T3), all implants remained osseointegrated (22/22 [100%]), with statistically insignificant mean midfacial gingival level change of -0.19 mm (-1.5 to 0.8). Statistically significant difference in midfacial gingival thickness (MFGT) was noted (2.5 mm [1.8-3.5 mm]) after a mean follow-up time (T2) of 2.3 years (1-8.6) when compared with MFGT at baseline (1.1 mm [0.6-1.3 mm]) (T1). Necrosis of S-CTG during initial healing phase was noted in 9% (2/22) of the sites. CONCLUSIONS: Within the confines of this study, scarf-connective tissue graft at time of immediate implant placement and provisionalization can thicken the gingiva and maintain the gingival level at the critical soft tissue zone. CLINICAL SIGNIFICANCE: Managing the soft tissue zone is as important as that of the hard tissue zone for peri-implant esthetics. Connective tissue graft is one of the methods that can enhance the final esthetic outcomes. This retrospective study has demonstrated that Scarf-CTG technique is an effective treatment modality to maintain soft tissue stability.

Vertical bone augmentation utilizing a titanium-reinforced PTFE mesh: A multi-variate analysis of influencing factors.

OBJECTIVE: To clinically evaluate the use of a titanium-reinforced PTFE mesh for vertical bone augmentation (VBA) of deficient alveolar ridges. MATERIALS AND METHODS: This case series documented consecutive patients treated for VBA with a newly developed PTFE mesh. VBA was performed in anterior and posterior, maxillary and mandibular arches using anorganic bovine bone combined with autogenous graft in a 1:1 ratio. Healing time from initial surgery to re-opening was recorded. Baseline vertical deficiency, absolute bone gain (gross height gained), and relative gain (percentage of defect fill with respect to the baseline deficiency) were registered. RESULTS: Fifty-seven patients (65 defects) were included in the analysis. The mean baseline vertical deficiency was 5.5 ± 2.6 mm. The mean absolute bone gain was 5.2 ± 2.4 mm. A relative gain of 96.5 ± 13.9% was achieved. Overall, 89.2% of cases showed complete regeneration, which occurred in all sites with baseline deficiencies of <5 mm, in 95.6% of sites with 5-8 mm deficiencies, and in 89.4% of sites with >8 mm deficiencies. Each 1-mm addition to the baseline height deficiency increased the likelihood of incomplete bone regeneration by 2.5 times. Defect location had a statistically significant but a limited clinical impact on the bone height gained (<0.5 mm). Complications were observed in three cases (3%). CONCLUSIONS: Vertical bone augmentation with titanium-reinforced PTFE mesh and a mixture of autologous bone and xenograft is a safe and predictable procedure. The extent of the baseline vertical deficiency influences the percentage of bone gained.

Long-term crestal bone changes in implants placed in augmented sinuses with minimal or moderate remaining alveolar bone: A 10-year retrospective case-series study.

OBJECTIVES: To evaluate long-term clinical and radiographic outcomes of dental implants placed after lateral window sinus augmentation utilizing the sagittal sandwich technique. MATERIALS AND METHODS: Patients treated with sinus augmentation were included in this retrospective case-series study. The surgical procedure was performed with particulate autogenous bone- and anorganic bovine bone-derived mineral (3:7 ratio). Implants were grouped based on baseline residual alveolar ridge height: group S (residual alveolar ridge height of 0.1-3.5 mm), group M (height of 3.5-7mm), and group C (native bone). Radiographs were taken at baseline (abutment installation) and annually throughout the 10-year follow-up. RESULTS: A total of 86 patients (92 sinus lifts) and 209 implants were included. Ten sinus membrane perforations were recorded (11% incidence), and graft infections occurred in 3 cases (3.2% incidence). During the 10-year follow-up, 3 implants (1.4%) failed. No significant differences in the mean implant marginal bone loss (MBL) between the three groups were found after 1-, 2-, and 5-year follow-up (p > .05). At 10 years, group C exhibited more MBL than group M with a mean difference of -0.53 mm (p = .01). After 10 years, MK III implants displayed significantly more bone loss in native bone than those in augmented bone with a mean difference of 0.48 mm (p = .02). Five patients and 7 implants developed peri-implantitis with no significant differences between the groups (p = .570). CONCLUSION: Implant placement after two-stage sinus grafting utilizing the sagittal sandwich technique is a relatively safe and predictable procedure with minimal complications and MBL after 10-year follow-up.

Accuracy of complete-arch implant impression made with occlusal registration material.

STATEMENT OF PROBLEM: Which impression material, impression tray type, and implant impression technique combination produces the most accurate complete-arch impression is unclear. PURPOSE: The purpose of this in vitro study was to compare the implant impression accuracy of a completely edentulous arch made with addition silicone occlusal registration material and an open tray with the implant impression accuracy of other conventional impression techniques. MATERIAL AND METHODS: A master cast was fabricated from Type IV gypsum with four 3.8-mm diameter implants with internal hexagon located in the area of mandibular canines and first molars. Impressions (N=60) were made from the master cast using the 6 techniques investigated: group B-OC-N with occlusal registration impression material (B), open custom tray (OC), and nonsplinted impression pins (N); group B-OS-N with occlusal registration impression material (B), open plastic perforated stock tray (OS), and nonsplinted impression pins (N); group PE-OC-N with polyether medium-body impression material (PE), open custom tray (OC), and nonsplinted impression pins (N); group PE-OC-S with polyether medium-body impression material (PE), open custom tray (OC), and impression pins splinted (S) with autopolymerizing resin cut after 17 minutes and reconnected; group PE-CC-N with polyether medium-body impression material (PE), closed custom tray (CC), and nonsplinted impression pins (N); group PVS-CS-N with simultaneous double-mix polyvinyl siloxane impression material (PVS), closed stock perforated metal tray (CS), and nonsplinted impression pins (N). Type IV gypsum casts were fabricated 24 hours after making the impressions. A computerized numerical control 3D coordinate measuring machine was used to measure the absolute differences of the distances between the centroids of the 4 implants among the casts produced and the distances measured at the master cast. The Kruskal-Wallis test was used to determine differences among the experimental groups (α=.05). The Mann-Whitney U post hoc analysis was used for all group combinations. RESULTS: No significant differences were found between the test groups B-OC-N and PE-OC-S, which were more accurate than the other groups. Group B-OS-N resulted in the least accurate impressions of all experimental groups. Group PE-OC-S resulted in more accurate impressions than the PE-OC-N group. No statistically significant differences were found between groups PE-OC-N and PE-CC-N or between groups PVS-CS-N and PE-CC-N. CONCLUSIONS: For complete edentulism, the use of silicone occlusal registration material with an open custom tray and nonsplinted impression pins resulted in impressions as accurate as those produced with PE open custom tray with splinted impression pins. These 2 techniques resulted in more accurate impressions than the other 4 techniques studied.

Effectiveness of vertical ridge augmentation interventions: A systematic review and meta-analysis.

AIM: The primary aim of this systematic review was to evaluate the effect of various techniques used for vertical ridge augmentation on clinical vertical bone gain. MATERIAL AND METHODS: A protocol was developed to answer the following focused question: "In patients with vertical alveolar ridge deficiencies, how effective are different augmentation procedures for clinical alveolar ridge gain?" Randomized and controlled clinical trials and prospective and retrospective case series were included, and meta-analyses were performed to evaluate vertical bone gain based on the type of procedure and to compare bone gains in controlled studies. RESULTS: Thirty-six publications were included. Results demonstrated a significant vertical bone gain for all treatment approaches (n = 33; weighted mean effect = 4.16 mm; 95% CI 3.72-4.61; p < 0.001). Clinical vertical bone gain and complications rate varied among the different procedures, with a weighted mean gain of 8.04 mm and complications rate of 47.3% for distraction osteogenesis, 4.18 mm and 12.1% for guided bone regeneration (GBR), and 3.46 mm and 23.9% for bone blocks. In comparative studies, GBR achieved a significant greater bone gain when compared to bone blocks (n = 3; weighted mean difference = 1.34 mm; 95% CI 0.76-1.91; p < 0.001). CONCLUSIONS: Vertical ridge augmentation is a feasible and effective therapy for the reconstruction of deficient alveolar ridges, although complications are common.

Regeneration of alveolar ridge defects. Consensus report of group 4 of the 15th European Workshop on Periodontology on Bone Regeneration.

BACKGROUND AND AIMS: Bone augmentation procedures to enable dental implant placement are frequently performed. The remit of this working group was to evaluate the current evidence on the efficacy of regenerative measures for the reconstruction of alveolar ridge defects. MATERIAL AND METHODS: The discussions were based on four systematic reviews focusing on lateral bone augmentation with implant placement at a later stage, vertical bone augmentation, reconstructive treatment of peri-implantitis associated defects, and long-term results of lateral window sinus augmentation procedures. RESULTS: A substantial body of evidence supports lateral bone augmentation prior to implant placement as a predictable procedure in order to gain sufficient ridge width for implant placement. Also, vertical ridge augmentation procedures were in many studies shown to be effective in treating deficient alveolar ridges to allow for dental implant placement. However, for both procedures the rate of associated complications was high. The adjunctive benefit of reconstructive measures for the treatment of peri-implantitis-related bone defects has only been assessed in a few RCTs. Meta-analyses demonstrated a benefit with regard to radiographic bone gain but not for clinical outcomes. Lateral window sinus floor augmentation was shown to be a reliable procedure in the long term for the partially and fully edentulous maxilla. CONCLUSIONS: The evaluated bone augmentation procedures were proven to be effective for the reconstruction of alveolar ridge defects. However, some procedures are demanding and bear a higher risk for post-operative complications.

A multicenter randomized controlled trial using a novel collagen membrane for guided bone regeneration at dehisced single implant sites: Outcome at prosthetic delivery and at 1-year follow-up.

OBJECTIVES: To compare clinical performance of a novel resorbable non-cross-linked collagen membrane (CXP) with a reference membrane (non-cross-linked resorbable membrane; BG) for simultaneous implant placement and guided bone regeneration (GBR) at dehisced single implant sites. MATERIALS AND METHODS: Preliminary data from this randomized controlled trial were reported previously; this is the 12-month report. The primary outcome measure was defected height at 6 months post-GBR. Secondary outcomes included implant cumulative survival rate (CSR) and success rate since placement; bone level changes, pink esthetic score (PES), and patient satisfaction since definitive prosthesis delivery; patient quality of life since pretreatment; and the 1-year bleeding index. Non-parametric statistical analyses were performed. RESULTS: Among patients, 24 were treated with CXP and 25 with BG. The 1-year implant CSR and success rate were 100% (n = 42). Bone level change between definitive prosthetic delivery and 1 year was not significantly different between the CXP and BG groups (BG + 0.42 mm, CXP + 0.01 mm). The PES increased from 7.55 to 8.10 for the CXP group and from 6.48 to 7.48 for the BG group; 1-year bleeding indices were 0 (16 CXP, 18 BG) and 1 (4 CXP, 2 BG). Patient quality of life changed from an OHIP-14 score of 6.5 at pretreatment to 1.9 at 1 year. Overall satisfaction (visual analogue score) with function and esthetics was 9.9 and 9.7, respectively. Inter-group differences were not significant for assessed outcomes. No device-related adverse events were reported. CONCLUSIONS: The use of CXP and BG for simultaneous implant placement and GBR at dehisced implant sites similarly reduced defect height and improved secondary measures, indicating non-inferiority.

A multicenter randomized controlled clinical trial using a new resorbable non-cross-linked collagen membrane for guided bone regeneration at dehisced single implant sites: interim results of a bone augmentation procedure.

OBJECTIVE: To compare clinical performance of a new resorbable non-cross-linked collagen membrane, creos xenoprotect (CXP), with a reference membrane (BG) for guided bone regeneration at dehisced implant sites. MATERIALS AND METHODS: This randomized controlled clinical trial enrolled patients with expected dehiscence defects following implant placement to restore single teeth in the maxillary and mandibular esthetic zone and premolar area. Implants were placed using a two-stage surgical protocol with delayed loading. Bone augmentation material placed at the implant surface was immobilized with CXP or BG membrane. Soft tissue health was followed during the healing period, and the defect size was measured at reentry and 6 months after implant placement. RESULTS: Of the 49 included patients, 24 were treated with CXP and 25 with BG. Patient characteristics did not differ between the two arms. In the CXP arm, the defect height at implant insertion was (mean ± SD) 5.1 ± 2.1 mm (n = 24) and reduced at reentry by 81% to 1.0 ± 1.3 mm (n = 23). In the BG arm, the defect height at implant insertion was 4.9 ± 1.9 mm (n = 25) and reduced at reentry by 62% to 1.7 ± 2.1 mm (n = 24). Assuming a margin of non-inferiority of 1 mm, CXP was non-inferior to BG. Membrane exposure rate was highest at week 3 in both arms, reaching 16.7% for BG and 8.7% for CXP. CONCLUSIONS: The new resorbable non-cross-linked collagen membrane facilitates bone gain to support implant placement in expected dehiscence defects. The observed trend toward higher mean bone gain and lower exposure rate with CXP compared to BG should be further investigated.

Prognostic Classification System for Implant Recession Defects.

PURPOSE: The etiology and progression of periimplant mucogingival defects are multifactorial. As such, the aim of this study was to discern and discuss the key long-term prognostic factors that change the balance of homeostasis/regeneration in periimplant mucogingival and recession defects. MATERIALS AND METHODS: This report provides cases and a discussion of anatomical factors that affect the long-term maintenance of periimplant soft tissue. RESULTS: The factors guiding long-term maintenance of the periimplant soft tissue apparatus are increasingly complex due to the additive combination of patient-related factors, anatomical variations, and unique material-host interactions. CONCLUSIONS: Severity and number of these contributing factors should be considered before implant placement and/or in the treatment of periimplant defects to achieve the best esthetic and functional outcome. In addition, assessment of prognostic factors should be used to provide the patient a realistic, long-term assessment of the esthetic and functional stability of both implant and the surrounding periimplant tissues.

Decision Tree for Reconstructive Treatment of Peri-implantitis Defects.

Peri-implantitis, a common complication among patients receiving implant-supported restorative therapy, often requires surgical intervention for effective treatment. Understanding the specific configuration of peri-implant bony defect and adjacent bone peaks is crucial for tailoring treatment strategies and improving outcomes. A decision tree for reconstructive peri-implantitis therapy has been developed based on the new classification of defect configurations (Class I to V), guiding clinicians in selecting treatment options, including biomaterials, techniques, and healing approaches. Furthermore, clinicians are encouraged to consider various factors such as local predisposing factors (such as soft tissue characteristics, prosthetic design, and implant position in three-dimensional perspective), clinical factors (surgeon skill and experience), and patient-related factors (such as local and systemic health, preferences, and cost) when evaluating reconstructive therapy options.

Management of the Lingual Flap During Vertical Augmentation of the Atrophic Anterior Mandible: Anatomical Overview and Description of the Technique.

Vertical ridge augmentation in the anterior mandible is a technically delicate procedure that requires knowledge of some anatomical structures to reduce intra- and postoperative complications. Proper soft tissue management is one of the primary aspects to the success of these techniques, enabling tension-free primary wound closure and preventing membrane exposure. This cadaveric and clinical study provides an anatomical overview of the lingual portion of the anterior mandible. Moreover, there is a description of a novel surgical approach for release of the lingual flap that will help clinicians achieve primary closure without incurring intrasurgical complications.

The Clinical Relevance of the Lingual Branch in Ridge Augmentation of the Posterior Mandible: A Pilot Cadaver Study.

Guided bone regeneration (GBR) requires a tension-free flap without damaging the collateral circulation in order to secure better surgical outcomes. Topographic knowledge regarding the neurovascular bundles in the posterior aspect of the mandible can prevent complications during lingual flap design. The lingual branch (LB) of the inferior alveolar or maxillary arteries is not sufficiently illustrated or described in the literature. Nevertheless, it has an intimate relationship with the lingual nerve (LN) during ridge augmentation and implant-related posterior mandible surgery. Therefore, this study aimed to clarify the morphology and topography of the LB related to GBR surgeries. In the present human cadaveric study, the LB was analyzed in 12 hemimandibles using latex injection and corrosion casting. Two types of LB were identified based on their origin and course. The LB was found in a common connective tissue sheath close to the LN. The LB assembled several anastomoses on the posterior lingual aspect of the mandible and retromolar area. The LB acted as an anatomical landmark in identifying LN at the posterior lingual aspect of the mandible.

The influence of vertical ridge augmentation techniques on peri-implant bone loss: A systematic review and meta-analysis.

INTRODUCTION: The primary aim of this systematic review was to investigate and compare the outcomes of different vertical ridge augmentation (VRA) techniques in relation to peri-implant bone loss (PBL), after at least 12 months of functional loading. MATERIAL AND METHODS: The search was conducted to find all the studies about VRA and measurements of PBL with at least 12 months follow-up. Three pairwise meta-analysis (MA) was performed to completely evaluate the outcomes. RESULTS: A total of 42 studies were included, of which 11 were randomized clinical trials (RCTs). RCTs were available only for guided bone regeneration (GBR), onlay, and inlay techniques. The weighted mean estimate (WME) of PBL value was found to be 1.38 mm (95% confidence interval [95% CI]: 1.10-1.66) after a mean follow-up of 41.0 ± 27.8 months. GBR, Inlay, Onlay, osteodistraction, and SBB represented in weight 32.9%, 30.6%, 25.0%, 7.6%, and 3.9%, respectively; and their WME (95% CI) were 1.06 (0.87-1.26) mm, 1.72 (1.00-2.43) mm, 1.31 (0.87-1.75) mm, 1.81 (0.87-1.75) mm, and 0.66 (0.55-0.77) mm, respectively. Among the secondary outcomes, the analysis was conducted for vertical bone gain, healing complication rate, surgical complication rate, implant survival, and success rate. CONCLUSIONS: The primary findings of the meta-analysis, based on the changes between final and baseline values, showed that the peri-implant bone loss could be influenced by the type of intervention but there is a need to evaluate in RCTs the behavior of the peri-implant bone levels after long-term follow-up for all techniques.

Elucidating the Benefit of Perforated vs Non-Perforated Membranes in Guided Bone Regeneration: An in Vivo Histologic Evaluation and Histomorphometric Analysis.

Background: Non-perforated Polytetrafluoroethylene (PTFE) membranes are effectively utilized in guided bone regeneration (GBR) but may hinder cell migration due to limited interaction with the periosteum. This study compared bone regeneration using occlusive or perforated membranes combined with acellular collagen sponge (ACS) and recombinant human bone morphogenic protein-2 (rhBMP-2) in a canine mandibular model. Material and Methods: Male beagle dogs (n=3) received two mandibular defects each to compare ACS/rhBMP-2 with experimental (perforated group) and control (non-perforated group) membranes (n=3 defects/group). Tissue healing was assessed histomorphologically, histomorphometrically and through volumetric reconstruction using microcomputed tomography. Results: The perforated group showed increased bone formation and reduced soft tissue formation compared to the non-perforated group. For the primary outcome, histomorphometric analysis revealed significantly greater total regenerated bone in the perforated group (67.08 ± 6.86%) relative to the nonperforated group (25.18 ± 22.44%) (p = 0.036). Perforated membranes had less soft tissue infiltration (32.91 ± 6.86%) compared to non-perforated membranes (74.82 ± 22.44%) (p = 0.036). Conclusion: The increased permeability of membranes in the perforated group potentially enabled periosteal precursor cells greater accessibility to rhBMP-2. The availability may have accelerated their differentiation into mature bone-forming cells, contributing to the stimulation of new bone production, relative to the non-perforated group.

Influence of residual pockets on periodontal tooth loss: A retrospective analysis.

BACKGROUND: Individuals enrolled in supportive periodontal therapy (SPT) can still present with tooth loss due to periodontitis (TLP). There is limited evidence on the influence of residual pockets (RPc) and a defined "threshold" at which a patient's profile is set to be at high risk for TLP in the literature. Therefore, this study aimed to assess the influence of RPc on TLP and determine the prognostic performance of RPc compared to the staging and grading of periodontitis on TLP risk. METHODS: Clinical data from 168 patients (3869 teeth) treated for periodontitis and receiving SPT for at least 10 years were evaluated in this retrospective study. TLP and the percentage of sites with RPc ≥ 5 mm or ≥6 mm per patient were collected. The prognostic performance of RPc was compared to the staging and grading of the disease on TLP using a multilevel Cox proportional hazard regression model. RESULTS: Over a median follow-up of 25 years, 13.7% of teeth were lost, 4.6% of which were due to periodontitis. Most patients with TLP had ≥1 site with RPc ≥5 mm (90.8%) or ≥6 mm (77.6%). Multivariate multilevel Cox regression revealed that patients with >15% of sites with RPc ≥5 mm had a hazard ratio of 2.34, and grade C had a hazard ratio of 4.6 for TLP compared to RPc ≤4 mm/grade A. Grading exhibited the best discrimination and model fit. CONCLUSION: Patients with RPc ≥5 mm at >15% of the sites are at risk for tooth loss. Grading and RPc ≥5 mm displayed very good predictive capability of TLP.