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.

Short (≤6 mm) compared with ≥10-mm dental implants in different clinical scenarios: A systematic review of randomized clinical trials with meta-analysis, trial sequential analysis and quality of evidence grading.

AIM: To systematically identify, synthesize and critically summarize the available scientific evidence from randomized controlled trials (RCTs) regarding whether short (≤6 mm) perform as well as long (≥10 mm) implants regarding implant survival, marginal bone loss, and biologic and prosthetic complications in different clinical scenarios. MATERIALS AND METHODS: Cochrane Collaboration's risk of bias tool and the GRADE approach were applied. Results were synthesized using random-effects meta-analyses assessed by trial sequential analyses. RESULTS: Forty reports on 19 RCTs comprising 2214 (1097 short; 1117 long) implants were included. Moderate/high certainty/quality evidence demonstrated similar 5-year survival rates for ≤6-mm and ≥10-mm implants in non-augmented bone and full-mouth rehabilitation in either jaw, and for 6-mm implants in the maxilla instead of sinus lift. Nevertheless, the evidence for 5-year survival rates remains inconclusive or insufficient for the remaining combinations of implant lengths and clinical scenarios. They include 4-mm and 5-mm implants as alternatives to sinus lift as well as placing all implant lengths ≤6 mm instead of vertical ridge augmentation with long implants. Marginal bone level and short- and long-term biologic or prosthetic complications were similar. CONCLUSIONS: Based on moderate/high certainty/quality evidence from 5-year RCTs, implants ≤6 mm may be viable alternatives to ≥10-mm implants in either jaw in native bone and full-arch rehabilitation, and 6-mm implants may be used as an alternative to sinus lift. TRIAL REGISTRATION: PROSPERO ID: CRD42021254365.

History of periodontitis as a risk factor for implant failure and incidence of peri-implantitis: A systematic review, meta-analysis, and trial sequential analysis of prospective cohort studies.

INTRODUCTION: Dental implants are widely employed as dependable replacements for lost teeth. However, it is crucial to establish, solely through prospective cohort studies, whether a history of periodontitis indeed constitutes a significant risk factor for implant failure. METHODS: A systematic literature search was conducted in October 2022 in several electronic databases with subsequent manual updates. Only original prospective cohort studies evaluating the implant (loss) rate ≥1 year after implant loading were included. Logarithmic risk ratio and weighted mean differences were calculated. Study results were summarized using random effects meta-analyses evaluated by trial sequential analyses. The Newcastle-Ottawa scale evaluated study bias and the GRADE approach assessed the certainty/quality of the evidence. RESULTS: A total of 14 publications reporting on 12 prospective cohort studies were included. Low evidence certainty/quality evidence due to the absence of randomized clinical trials revealed significantly greater odds of failure in patients with a history of periodontitis at follow-ups both after ≤5 years (OR = 1.65; 95% CI: 1.12-2.44; p = 0.012) and >5 years (OR = 2.36; 95% CI: 1.13-4.95; p = 0.023). The incidence of peri-implantitis (OR = 5.93; 95% CI: 2.75-12.8; p < 0.001) and the weighted mean (WM) of marginal bone loss (WM difference = 0.75 mm; 95% CI: 0.18-1 0.3; p < 0.05) were statistically significantly greater in the periodontally compromised group, whereas there was no significant difference between the two groups for peri-implant probing depth. CONCLUSION: A history of periodontitis can be considered a significant risk factor for incident implant failure, peri-implantitis, and greater marginal bone loss.

Periodontitis stage and grade modifies the benefit of regular supportive periodontal care in terms of need for retreatment and mean cumulative cost.

AIM: This study aimed to characterize the periodontal breakdown during supportive periodontal care (SPC) and to quantify the corresponding cost-effectiveness of periodontal therapy. MATERIALS AND METHODS: Data were obtained from charts of patients who received active periodontal therapy (APT) with a minimum follow-up of ≥10 years. Analysis was done to identify factors associated with the incidence of additional sub-gingival instrumentation (SGI) and/or surgery (SUR) during SPC and mean cumulative cost of recurrence was calculated. All relevant data were collected. RESULTS: In all, 442 patients were included. Over the follow-up period, 62% of Stage I and II patients and 72% of Stage III and IV patients required further treatment following the APT; 56.5% of SGI patients and 78.6% of SUR patients received a second intervention. SUR patients received more SUR during the follow-up period (p = .035). Stage III and IV patients received more SUR during SPC than Stage I and II patients (p = .001). Grade C patients received more SUR during the follow-up period (p < .05). During the 5-year period preceding retreatment, the mean SPC visits were lower for patients who did not require retreatment (p < .001). Risk factors such as regularity of maintenance, smoking and diabetes were related to a higher chance of receiving SUR during the follow-up period (p < .05). The mean cumulative costs indicated less recurrence cost for compliers in Stage III and IV or Grade B and C but not for those in Stage I and II or Grade A. CONCLUSIONS: The risk of relapse in the maintenance population may be correlated with higher stage and grade, patient compliance, modifiable risk factors and the nature of the treatment provided during APT. The total cost of treatment of recurrences was lower for compliers in Stage III/IV and Grade B/C compared with erratic compliers with the same severity and risk.

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.

Clinical outcomes of implant- versus abutment-level connection in screw-retained fixed dental prostheses: A 5-year randomized controlled trial.

AIM: The aim of the study was to evaluate the 5 years clinical outcomes associated with implant-level connection (IL) versus abutment-level connection (AL) for implants with an internal conical connection (ICC) supporting a screw-retained fixed partial denture. MATERIALS AND METHODS: Fifty patients with 119 implants were randomly allocated to either the AL or IL group. Radiographic (Marginal bone loss) and clinical outcomes (Bleeding on Probing, probing pocket depth, plaque accumulation, incidence of peri-implantitis and peri-implant mucositis as well as prosthetic complications) were collected and compared at 1, 2, 3, and 5 years. A linear mixed model was used to evaluate the differences between groups. RESULTS: Five years after treatment, the MBL change was not significantly different between the groups at any point. The MBL was 0.23 ± 0.64 mm (AL) and 0.23 ± 0.29 mm (IL). The bleeding on Probing was 44% (AL) and 45% (IL) (p = .89). The mean probing depth was 2.91 ± 1.01 mm (AL) and 3.51 ± 0.67 mm (IL). This difference between the groups was statistically significant but clinical insignificant. Presence of plaque was slightly higher (p = .06) in the IL group (34.4%) compared with the AL group (26.3%). The overall technical, biological, and prosthetic complication rates were similar between groups. None of the implants developed peri-implantitis during the entire follow-up period. CONCLUSION: The results of this clinical trial indicated that all clinical and radiographical parameters were clinically comparable between the study groups.

Avoiding implant-related complications in medically compromised patients with or without unhealthy lifestyle/Elevated oxidative stress.

Increased human life expectancy broadens the alternatives for missing teeth and played a role in the widespread use of dental implants and related augmentation procedures for the aging population. Though, many of these patients may have one or more diseases. These systemic conditions may directly lead to surgical complications, compromise implant/bone healing, or influence long-term peri-implant health and its response to biologic nuisances. Offering patients credible expectations regarding intra- and postoperative complications and therapeutic prognosis is an ethical and legal obligation. Clear identification of potential types of adverse effects, complications, or errors is important for decision-making processes as they may be related to different local, systemic, and technical aspects. Therefore, the present review structures the underlying biological mechanisms, clinical evidence, and clinical recommendations for the most common systemic risk factors for implant-related complications.

Extra-short (4-mm) implants placed after regenerative failures in the posterior atrophic mandible: A retrospective study.

PURPOSE: To explore whether extra-short (4-mm) implants could be used to rehabilitate sites where regenerative procedures had failed in order to avoid additional bone grafting. MATERIALS AND METHODS: A retrospective study was conducted among patients who had received extra-short implants after failed regenerative procedures in the posterior atrophic mandible. The research outcomes were complications, implant failure and peri-implant marginal bone loss. RESULTS: The study population was composed of 35 patients with 103 extra-short implants placed after the failure of different reconstructive approaches. The mean follow-up duration was 41.3 ± 21.4 months post-loading. Two implants failed, leading to a failure rate of 1.94% (95% confidence interval 0.24%-6.84%) and an implant survival rate of 98.06%. The mean amount of marginal bone loss at 5 years post-loading was 0.32 ± 0.32 mm. It was significantly lower in extra-short implants placed in regenerative sites that had previously received a loaded long implant (P = 0.004). Failure of guided bone regeneration before placement of short implants tended to lead to the highest annual rate of marginal bone loss (P = 0.089). The overall rate of biological and prosthetic complications was 6.79% (95% confidence interval 1.94%-11.70%) and 3.88% (95% confidence interval 1.07%-9.65%), respectively. The success rate was 86.4% (95% confidence interval 65.10%-97.10%) after 5 years of loading. CONCLUSIONS: Within the limitations of this study, extra-short implants seem to be a good clinical option to manage reconstructive surgical failures, reducing surgical invasiveness and rehabilitation time.

Papilla reconstruction using a vertical interproximal tunnel approach.

INTRODUCTION: Papilla reformation is one of the most difficult and elusive surgical techniques for clinicians. Although it involves similar tenets to those applied for soft tissue grafting at recession defects, crafting a small tissue in restricted space remains unpredictable. Numerous grafting techniques have been developed to correct interproximal and buccal recession, but so far, only a limited number of techniques have been prescribed for interproximal remediation. CASE PRESENTATION: This report describes in detail a modern technique (the vertical interproximal tunnel approach) for reforming the interproximal papilla and treating interproximal recession. It also documents three challenging cases of papilla loss. The first case presented Class II papilla loss and a recession type 3 gingival defect adjacent to a dental implant, managed using the vertical interproximal tunnel approach through a short vertical incision. A 6-mm increase in attachment level and almost complete papilla fill were observed in this case with this surgical technique for papilla reconstruction. The second and third cases presented Class II papilla loss between two adjacent teeth, managed using the vertical interproximal tunnel approach through a semilunar incision and achieving full papilla reconstruction. CONCLUSION: Both described incision designs for the vertical interproximal tunnel approach require technical meticulousness. When executed carefully and using the most beneficial pattern of blood supply, predictable reconstruction of the interproximal papilla can be achieved. It also helps alleviate concerns associated with inadequate flap thickness, blood supply and flap retraction.

Effect of argon plasma pre-treatment of healing abutments on peri-implant microbiome and soft tissue integration: a proof-of-concept randomized study.

PURPOSE: Biofilm-free implant surface is ultimate prerequisite for successful soft and bone tissue integration. Objective of the study was to estimate the effects of argon plasma healing abutment pre-treatment (PT) on peri-implant soft-tissue phenotype (PiSP), inflammation, plaque accumulation and the microbiome (PiM) between non-treated (NPT) and treated (PT) abutments following 3-months healing period. The hypothesis was that cell-conductive and antimicrobial properties of PT would yield optimal conditions for soft tissue integration. MATERIAL AND METHODS: Two months following second-phase surgery, microbiological and clinical parameters were assessed around thirty-six healing abutments with two types of microtopography, smooth surface (MACHINED) and ultrathin threaded microsurface (ROUGH). A two level randomization schema was used to achieve equal distribution and abutments were randomly divided into rough and machined groups, and then divided into PT and NPT groups. PiM was assessed using next-generation DNA sequencing. RESULTS: PiM bacterial composition was highly diverse already two months post-implantation, consisting of key-stone pathogens, early and late colonizers, while the mycobiome was less diverse. PT was associated with lower plaque accumulation and inflammation without significant impact on PiSP, while in NPT clinical parameters were increased and associated with periopathogens. NPT mostly harbored late colonizers, while PT exerted higher abundance of early colonizers suggesting less advanced plaque formation. Interaction analysis in PT demonstrated S. mitis co-occurrence with pro-healthy Rothia dentocariosa and co-exclusion with Parvimonas micra, Porphyromonas endodontalis and Prevotella oris. PiSP parameters were generally similar between the groups, but significant association between PiM and keratinized mucosa width was observed in both groups, with remarkably more expressed diversity in NPT compared to PT. PT resulted in significantly lower BOP and PI around rough and machined abutments, respectively, without specific effect on PiM and PiSP. CONCLUSIONS: PT contributed to significantly the less advanced biofilm accumulation and inflammation without specific effects on PiSP.

Minimally invasive gingival phenotype modification in gingival recession associated with a non-carious cervical lesion using the root plastique technique: A quasi-experimental one-group pretest-posttest study.

BACKGROUND: This study introduces the root plastique technique (RPT), the aim of which is to modify the gingival phenotype of sites with gingival recessions (GRs) associated with non-carious cervical lesions (NCCLs) prior to surgical treatment. METHODS: RPT was performed in 22 subjects with 53 RT1 A/B + GRs. Changes in keratinized tissue thickness (KTT), keratinized tissue width (KTW), relative gingival recession (RGR), relative clinical attachment level (RCAL), and probing pocket depth (PPD) were measured at baseline (T0) and 2 months (T1) after the procedure was performed. All analyses were performed by means of hierarchical models. RESULTS: The study revealed statistically significant changes (P < 0.01) in KTT (0.45 ± 0.04 mm), RGR (0.80 ± 0.13 mm), KTW (0.67 ± 0.07 mm), and RCAL (-0.72 ± 0.16 mm). No changes in PPD (P > 0.05) were observed. Regression analyses of KTT increase and RGR reduction at T0 showed statistically significant correlation between the two variables (P < 0.05). All the teeth with a KTT of <0.8 mm at T0 (N = 14) reached or surpassed this threshold at T1. CONCLUSION: RPT increases KTT and KTW. In most of the sites, a reduction in GR was also achieved.

Patient-reported outcomes of palatal donor site healing using four different wound dressing modalities following free epithelialized mucosal grafts: A four-arm randomized controlled clinical trial.

BACKGROUND: The aim of this study was to compare the effects of four different commonly used wound dressings in improving patient reported outcomes (PROMS) after free epithelialized mucosal grafts (FEGs) harvesting. METHODS: Following 72 FEGs harvesting from 72 patients, patients were assigned into four groups. CONTROL: collagen plug + sutures (CPS); test: collagen plug with cyano-acrylate (CPC), platelet rich fibrin (PRF) + sutures, or palatal stent only (PS). Patients were observed for 14 days, with evaluation of pain level utilizing the visual analog scale, number of analgesics consumed, need for additional analgesics, amount of swelling, amount of bleeding, activity tolerance, and willingness for retreatment. RESULTS: Compared to the control group all test groups indicated significant lower pain perception (P < 0.0001), lower analgesic consumption (P < 0.0001), and higher willingness for retreatment (P < 0.0001), while no statistically significant differences among test groups were observed. There were no statistically significant differences in amount of day-by-day swelling, bleeding, and activity tolerance among four groups. Compared to other groups, the PS had the lowest overall pain scores (over the 14-day period). Palatal thickness, graft length, graft width, and graft thickness did not appear to affect patient morbidity (P > 0.05). CONCLUSIONS: All interventions significantly decreased pain perception compared to a hemostatic collagen sponge alone over the palatal donor site after FEG surgery. In the first few days after surgery, the use of a palatal stent seemed to be associated with less overall pain, pain pills consumed, and higher willingness of doing the same procedure again.

Interproximal implant thread exposure after initial bone remodeling as a risk indicator for peri-implantitis.

BACKGROUND: Due to the clinical challenges involved in successfully treating peri-implantitis, it is imperative to identify patient- and implant-level risk factors for its prevention. The main goal of this retrospective longitudinal radiographic and clinical study was to investigate whether interproximal radiographic implant thread exposure after physiological bone remodeling may be a risk factor for peri-implantitis. The secondary goal was to evaluate several other potential risk indicators. METHODS: Of 4325 active dental school patients having implants placed, 165 partially edentulous adults (77 men, 88 women) aged 30-91 with ≥2 years of follow-up upon implant restoration were included. Implants with ≥1 interproximal thread exposed (no bone-to-implant contact) (n = 98, 35%) constituted the test group and those without exposed threads (n = 182, 65%) the control group. Descriptive, binary, and multivariate regression analyses were evaluated for goodness of fit. Wald tests were used to evaluate for significance set at 0.05. RESULTS: Of the 280 implants (98 test, 182 control), 8 (2.9%) failed over a mean follow-up period of 7.67 (±2.63) years, and 27 implants (19 test, 8 control) developed peri-implantitis, with the exposed group having eight-fold (7.82 times) adjusted greater odds than the non-exposed. The risk increased four-fold (3.77 times) with each thread exposed. No other patient- or implant-related potentially confounding risk factors were identified. CONCLUSIONS: Exposed interproximal implant threads after physiologic bone remodeling may be an independent risk indicator for incident peri-implantitis. Hence, clinicians should closely monitor patients with implant threads that have no bone-to-implant contact for incident peri-implantitis.

Periodontal risk score: Initiation and model validation for 6,762 teeth.

BACKGROUND: Tooth-level prognostic systems are valuable tools for treatment planning and risk assessment of periodontally involved teeth. Recently the Miller-McEntire prognosis index was found to outperform comparable systems. However, it had some limitations. The present study aimed to develop and evaluate the prognostic performance of a modified version that addresses most limitations of the previous model called the periodontal risk score (PRS). METHODS: Data were retrieved retrospectively from patients who received surgical and non-surgical periodontal treatment at a university setting. Data on medical history and smoking status at baseline and the last maintenance visit were collected. Both univariate and multivariate Cox proportional hazard regression models were used to analyze the prognostic capability for predicting tooth loss due to periodontitis (TLP) risk. RESULTS: A total of 6762 teeth (281 patients) were followed up for a mean period of 22.6 ± 6.34 (10-47.6y) years. The PRS was successfully able to stratify the risk of TLP at baseline when the three different classes of association were compared for anterior and/or posterior tooth loss. After controlling for maintenance, age, and sex, the index showed an excellent predictive capacity for TLP with a Harrell C-index of 0.947. CONCLUSIONS: The periodontal risk score (PRS) displayed excellent predictive capability for anterior as well as posterior tooth loss due to periodontitis. This system was able to predict long-term tooth loss with a very high accuracy  in a population treated mainly by dental students and periodontics residents. The use of this/similar prognosis system is advisable as a means to establish tooth prognosis.

Development and international validation of logistic regression and machine-learning models for the prediction of 10-year molar loss.

AIM: To develop and validate models based on logistic regression and artificial intelligence for prognostic prediction of molar survival in periodontally affected patients. MATERIALS AND METHODS: Clinical and radiographic data from four different centres across four continents (two in Europe, one in the United States, and one in China) including 515 patients and 3157 molars were collected and used to train and test different types of machine-learning algorithms for their prognostic ability of molar loss over 10 years. The following models were trained: logistic regression, support vector machine, K-nearest neighbours, decision tree, random forest, artificial neural network, gradient boosting, and naive Bayes. In addition, different models were aggregated by means of the ensembled stacking method. The primary outcome of the study was related to the prediction of overall molar loss (MLO) in patients after active periodontal treatment. RESULTS: The general performance in the external validation settings (aggregating three cohorts) revealed that the ensembled model, which combined neural network and logistic regression, showed the best performance among the different models for the prediction of MLO with an area under the curve (AUC) = 0.726. The neural network model showed the best AUC of 0.724 for the prediction of periodontitis-related molar loss. In addition, the ensembled model showed the best calibration performance. CONCLUSIONS: Through a multi-centre collaboration, both prognostic models for the prediction of molar loss were developed and externally validated. The ensembled model showed the best performance in terms of both discrimination and validation, and it is made freely available to clinicians for widespread use in clinical practice.

The effect of bone particle size on the histomorphometric and clinical outcomes following lateral ridge augmentation procedures: A randomized double-blinded controlled trial.

BACKGROUND: The aim of this randomized clinical trial was to clinically and histologically compare the amount and quality of bone gained after lateral ridge augmentation (LRA) procedures performed using small-particle (SP)-size (250-1000 µm) versus large-particle (LP)-size (1000-2000 µm) size corticocancellous bone allografts at 6 months following surgical intervention. METHODS: Twenty-two patients, each presenting with ridge width <5 mm were enrolled. Patients were randomly allocated to SP- and LP-size graft. The gain in ridge width at the level of the crest and 4 mm apical to the crest was assessed via a standardized procedure before grafting and at time of implant placement, using a surgical caliper and a novel digital technique using cone-beam computed tomography (CBCT). Six months following the procedure, trephine bone cores were taken from 19 augmented sites of 17 patients (14/19 sites were in the posterior mandible) who completed the study for clinical, histologic, and histomorphometric analysis. RESULTS: Seventeen patients (19 sites) completed the study. An LP-size graft resulted in greater ridge width gain at the level of the crest (LP 5.1 ± 1.7; SP 3.7 ± 1.3 mm; p = 0.0642) and 4 mm apical to the crest (LP 5.9 ± 2.2; SP 5.1 ± 1.8 mm; p = 0.4480) compared with the SP. No statistical significance for the bone density at the time of implant placement (p = 1.00) was found. Vital bone formation was more extensive in the SP compared with the LP (41.0 ± 10.1% vs. 31.4 ± 14.8%, respectively; p = 0.05). CONCLUSION: The results of the present study show a trend of higher ridge gain using LP during the bone augmentation procedure. Future research with bigger sample size should confirm the results of the present research.

Flap versus flapless alveolar ridge preservation: A clinical and histological single-blinded, randomized controlled trial.

BACKGROUND: The aim of this randomized clinical trial was to compare a flapless technique of alveolar ridge preservation (ARP) to a flap technique to determine if preserving the periosteal blood supply would limit loss of crestal ridge width and height. METHODS: Twenty-four patients were randomly assigned to receive ARP using either a flapless or flap technique. Sockets were grafted with demineralized bone matrix and mineralized particulate allograft then covered with a barrier in both groups. Re-entry was performed at 4 months to obtain samples for histological analysis and subsequent implant placement. RESULTS: Ridge width of the flapless group at the crest decreased from 8.3 ± 1.3 mm to 7.0 ± 1.9 mm for a mean loss of 1.3 ± 0.9 mm (p < 0.05), whereas the flap group decreased from 8.5 ± 1.5 mm to 7.5 ± 1.5 mm for a mean loss of 1.0 ± 1.1 mm (p < 0.05). The mean midbuccal vertical change for the flap group was a loss of 0.9 ± 1.3 mm (p < 0.05) versus 0.5 ± 0.9 mm (p < 0.05) for the flapless group. There was no statistically significant difference between the groups. Histologically, flapless ARP revealed more vital mineralized tissue (44 ± 10%) compared to the flap group (p>0.05). In the flapless group, the occlusal soft tissue was significantly thicker than in the flap group at the 4-month re-entry (p< 0.05). CONCLUSIONS: Crestal ridge width, height, and percentage of vital mineralized bone following treatment with a flapless ARP technique, was not significantly different from a flap technique.

Limited marginal bone loss in implant-supported fixed full-arch rehabilitations after 5 years of follow-up.

PURPOSE: The aim of the present study was to evaluate the 5-year results in terms of marginal bone level (MBL) around implants supporting fixed full-arch metal-ceramic restorations in a series of cases of patients who had lost their teeth in that dental arch because of severe periodontal disease. MATERIAL AND METHODS: A retrospective cohort study was designed to evaluate the 5-year MBL results of OsseoSpeed™ Astra Tech TX implants with internal tapered conical connection. Age, gender, bone substratum, smoking habits, history of periodontitis, and prosthetic features were recorded. Mixed linear model was used to determine the influence of the different variables on MBL. RESULTS: In this series, a total of 160 implants placed in 19 patients were evaluated. No implant failure was reported during the 5 years of follow-up. Only 14 (8.75%) implants had more than 2 mm of MBL. Abutment height, F(3,142) = 6.917, p < .001, and implant diameter, F(1,141) = 15.059, p < .001, were determined to be statistically associated with MBL. No other effect was significant. Pairwise comparisons showed that MBL was larger for abutment height = 1 (MBL = -0.987, SE = 0.186) compared with the remaining heights [-0.335 (0.171), -0.169 (0.192) and -0.247 (0.267), 2, 4 and 6 mm, respectively]. MBL was larger for narrow (-0.510, SE = 0.169) than for wide implants (-0.364, SE = 0.190). CONCLUSION: The current study demonstrates that the vast majority of internal conical connection implants supporting fixed full-arch metal-ceramic restorations do not suffer from relevant MBL after 5 years in function. Particularly, those implants with transmucosal abutments longer than 2 mm show less than 0.5 mm from the implant shoulder to the marginal bone.

Comparative analysis of two biomaterials mixed with autogenous bone graft for vertical ridge augmentation: A histomorphometric study in humans.

BACKGROUND: The vertical increase of the alveolar ridge dimension using allograft or xenograft mixed with autogenous bone graft and covered by a nonabsorbable high-density polytetrafluoroethylene (d-PTFE) membrane is well documented in the literature. PURPOSE: The aim of this study was to assess vital mineralized tissue formation in vertical ridge augmentation (VRA) procedures using autogenous bone chips mixed either with an allograft or a xenograft. METHODS: This prospective clinical trial recruited 16 partially edentulous patients to undergo vertical ridge augmentation in one or more sites, making up a total of 24 samples for histological evaluation. Patients were sequentially stratified into Group A (treated with a freeze-dried bone allograft [FDBA] mixed with autogenous bone) or to Group B (treated with a bovine xenograft mixed with autogenous bone). Histological samples were analyzed according to the biomaterial used for VRA. Histological samples were obtained on the same day of membrane removal and implant placement. RESULTS: Thirty-three implants were placed in 16 sites of regenerated bone via VRA, 13 patients with ridge augmentation in the posterior mandible, and 3 patients with VRA in the anterior maxilla. Group A (FDBA + autogenous) and Group B (xenograft + autogenous) showed a percent vital mineralized tissue (VMT) area of 67.64 ± 16.84 and 60.93 ± 18.25, respectively. A significant difference between the two biomaterials was not observed. CONCLUSION: When mixed with autogenous bone, either allografts or xenografts may provide a successful augmentation. Either mixture could serve as reliable alternative in VRA for obtaining a high percentage of VMT.

The Prosthetic-Biologic Connection and Its Influence on Peri-implant Health: An Overview of the Current Evidence.

Prosthetic design is a critical step in implant treatment planning that must synchronize with implant positioning to promote a state of peri-implant health. Improperly designed prostheses may not only hinder patient (or professional) hygiene measures but also impact the ability of clinicians to examine the peri-implant supporting tissues for diagnostic purposes. The purpose of this review was to discuss the current state of the evidence surrounding prosthetic factors associated with peri-implant diseases. Following the chronologic order of implant treatment, key prosthetic variables were discussed in relation to peri-implant disease pathogenesis. Specific concepts including the impact of implant spatial positioning, abutment height, residual cement, and implant splinting were found to be associated with peri-implant disease pathogenesis. Excessive occlusal forces were found to play a role in susceptibility to prosthetic complications with limited evidence to suggest a role in peri-implant disease progression. An intimate prosthetic-biologic connection exists, which must be respected to promote an environment for long-term peri-implant stability and health.