Histological and histomorphometric analysis of bone tissue using customized titanium meshes with or without resorbable membranes: A randomized clinical trial.

OBJECTIVES: To date, no clinical studies have investigated the effect of using resorbable collagen membrane in conjunction with customized titanium mesh to promote bone formation in guided bone regeneration. Therefore, a non-inferiority analysis (one-sided 95% CI approach) was designed to compare the augmented bone gained using meshes with and without collagen membranes, through histological and histomorphometric investigations. MATERIALS AND METHODS: Thirty patients undergoing bone augmentation procedures at both maxillary and mandible sites were randomly treated with customized titanium meshes alone (M-, n = 15) or covered with resorbable membrane (M+, n = 15), in both cases filled with autogenous bone and xenograft. After 6 months of healing, bone tissue biopsies were taken from the augmented region. The bone tissue (B.Ar), grafting material (G.Ar), and non-mineralized tissue (NMT.Ar) areas were quantified through histomorphometric analysis, as were the osteoid area (O.Ar) and its width. RESULTS: Collagen membrane did not appear to significantly influence the investigated parameters: B.Ar, G.Ar, NMT.Ar, and O.Ar were similar between Group M- (34.3%, 11.5%, 54.1%, 1.95 µm2 , respectively) and Group M+ (35.3%, 14.6%, 50.2%, and 1.75 µm2 , respectively). Considering the overall population, significantly higher rates of newly formed bone were obtained in mandibular sites, while non-mineralized and dense connective tissue rates were higher in the maxilla (p < .05). CONCLUSIONS: The application of collagen membrane over titanium mesh did not lead to significant results. Bone formation appeared significantly different in the maxilla compared with the mandible. Additional studies are required to further investigate the issues observed.

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.

Effectiveness of Bichat's Buccal Fat Pad (BFP) Technique for Vertical Ridge Augmentation in the Maxilla.

This study evaluated the efficacy of buccal fat pad (BFP) as a natural barrier to cover nonresorbable devices for vertical ridge augmentation (VRA). Twelve consecutive patients with 14 vertical bone defects in need of bone augmentation for implantprosthetic rehabilitation were treated according to the described protocol. VRA was performed by means of customized titanium meshes, titanium-reinforced d-PTFE membranes, or resorbable membranes and titanium plates. After buccal flap release, the BFP was identified and isolated, then mesially and coronally advanced to cover the whole augmented area. BFP was used as a pedicle flap in 11 cases and as a free graft in 3 cases. The mean BFP surface area was 13.5 ± 5.5 cm2. Healing was uneventful in all 14 augmented sites. No patients reported healing complications or facial volumetric changes. The mean vertical bone gain (VBG) was 4.2 ± 1.8 mm. In this limited number of cases, using the BFP as a natural barrier has proven to be efficient in bone augmentation, as it improved the healing process while reducing the risk of complications. Int J Periodontics Restorative Dent 2023;43:e99-e109. doi: 10.11607/prd.5473.

Vertical ridge augmentation with Ti-reinforced dense polytetrafluoroethylene (d-PTFE) membranes or Ti-meshes and collagen membranes: 3-year results of a randomized clinical trial.

BACKGROUND: The present study aimed to evaluate hard and soft tissue parameters around implants placed in augmented posterior mandible, comparing Ti-reinforced d-PTFE membranes with Ti-meshes covered with collagen membranes, after 3 years of follow-up. MATERIALS AND METHODS: Forty eligible patients were randomly assigned to group A (Ti-reinforced d-PTFE membrane) or group B (mesh covered with collagen membrane) for vertical ridge augmentation (VRA) and simultaneous implants. Implants were evaluated using specific peri-implant parameters for bone and soft tissues: probing pocket depth (PPD), modified plaque index (mPI), bleeding on probing (BoP), modified gingival index (mGI), thickness of keratinized tissue (tKT), width of keratinized tissue (wKT), fornix depth (FD), peri-implant bone level (PBL), interproximal bone peaks (IBP), marginal bone loss (MBL), interproximal bone loss (IBL). RESULTS: A total of 28 patients with 79 implants were evaluated after 3 years of follow-up. The mean value of MBL was 0.70 mm (group A = 0.73 mm; group B = 0.71 mm), while mean IBL was 0.54 mm (group A = 0.64 mm; group B = 0.40 mm). The treatment with meshes resulted not inferior to PTFE and their clinical results appeared similar. A strong correlation between PBL and IBP was confirmed. Both study groups showed an increase of tKT and wKT values. CONCLUSION: In the posterior mandible, VRA using both techniques provides stable PBLs up to 3 years. A correct soft tissue management and a strict professional oral hygiene protocol play a crucial role on peri-implant health over time.

Effectiveness Of Bichat's Buccal Fat Pad (BFP) Technique For Vertical Ridge Augmentation In The Maxilla.

The aim of this study was to evaluate the efficacy of buccal fat pads (BFP) as a natural barrier to cover nonresorbable devices for vertical ridge augmentation (VRA). A total of 12 consecutive patients with 14 vertical bone defects in need of bone augmentation for implant-prosthetic rehabilitation were treated according to the described protocol. VRA was performed by means of (1) customized titanium meshes, (2) titanium-reinforced PTFE membranes, or (3) resorbable membranes plus titanium plates. After buccal flap release, the BFP was identified, isolated, then mesially and coronally advanced to cover the whole augmented area. BFP was used as a pedicle flap in 11 cases and as free graft in 3 cases. The mean surface of the BFP obtained was 13.5 ± 5.5 cm2. In all 14 augmented sites, uneventful healing was assessed. No patients reported healing complications or facial volumetric changes. The mean VBG was 4.2 ± 1.8 mm. In this limited number of cases, the technique using the BFP as a natural barrier has proven to be efficient in bone augmentation, as it has shown to improve the healing process while reducing the risk of complications.

A novel technique for digitalisation and customisation of reinforced polytetrafluoroethylene meshes: Preliminary results of a clinical trial.

PURPOSE: To evaluate the clinical, radiographic and patient-related outcomes of a novel technique for digitalisation and customisation of reinforced polytetrafluoroethylene meshes in vertical ridge augmentation surgery. MATERIALS AND METHODS: A total of 10 patients (five men and five women, mean age 54 years) with vertical defects were included in the study. Prior to surgery, digital planning of bone augmentation, manufacturing of 3D printed models and replicas of the meshes and modelling of a customised reinforced polytetrafluoroethylene mesh were carried out. All patients were treated using a 50:50 mixture of xenogeneic and autogenous bone, customised reinforced polytetrafluoroethylene mesh and collagen membrane. After 6 to 9 months, computer-guided surgery was planned, the reinforced polytetrafluoroethylene mesh was removed and implants were placed in augmented sites using a fully guided surgical template. Patient-related outcomes, intraoperative timing, surgical and healing complications, vertical bone gain, bone density, pseudoperiosteum type and number and stability of implants were recorded. RESULTS: All 10 patients were treated without surgical complications. Healing was largely uneventful, with the exception of one case of abscess formation without mesh exposure (exposure rate 0%). The mean duration of digital planning was 17.0 minutes, reinforced polytetrafluoroethylene mesh customisation took 9.0 minutes, and the total intraoperative time was 91.3 minutes. The mean planned bone volume was 1.52 cc, vertical bone defect depth was 6.0 ± 1.7 mm and vertical bone gain was 5.5 ± 1.9 mm; most sites showed medium bone density and a Type 1 pseudoperiosteum. All patient-related outcomes were favourable. CONCLUSIONS: The preliminary results of this pilot study demonstrated the feasibility and reliability of a fully digital workflow for the customisation of reinforced polytetrafluoroethylene mesh in vertical ridge augmentation.

Guided bone regeneration using titanium mesh to augment 3-dimensional alveolar defects prior to implant placement. A pilot study.

OBJECTIVES: To evaluate the outcomes of bone regeneration using a customized titanium mesh scaffold to cover a bone graft for reconstruction of complex defects of the jaws. MATERIALS AND METHODS: 19 large defects were digitally reconstructed using CT scans according to the prosthetic requirements. A titanium mesh scaffold was designed to cover the bone (autologous/bovine bone particulate) graft. At least 6 months after surgery, a new cone-beam CT was taken. The pre- and postoperative CT datasets were then converted into three-dimensional models and digitally aligned. The actual mesh position was compared to the virtual position to assess the reliability of the digital project. The reconstructed bone volumes (RBVs) were calculated according to the planned bone volumes (PBVs), outlining the areas under the mesh. These values were then correlated with the number of exposures, locations of atrophy, and virtually planned bone volume. RESULTS: The mean matching value between the planned position of the mesh and the actual one was 82 ± 13.4%. 52.3% (40% early and 60% late) exposures were observed, with 15.8% exhibiting infection. 26.3% resulted as failures. The amount of reconstructed bone volume (RBV) in respect to PBV was 65 ± 40.5%, including failures, and 88.2 ± 8.32% without considering the failures. The results of the exposure event were statistically significant (p = .006) in conditioning the bone volume regenerated. CONCLUSIONS: This study obtained up to 88% of bone regeneration in 74% of the cases. The failures encountered (26%) should underline the operator's expertise relevance in conditioning the final result.

Preliminary Study with the Use of a Titanium Mesh as Space Maker and Implant Primary Stabilization for One-Stage Sinus Lift in Cases with Less Than 1.5 mm Residual Bone.

(1) Background: In the lateral area of the maxilla, the alveolar bone can lose significant volume due to maxillary sinus pneumatization following teeth extractions. This preliminary study evaluated the effectiveness of a novel technique for one-stage sinus lifting and simultaneous implant placement in cases with less than 1.5 mm residual alveolar bone. The subsequent survival rate at 1-year post-occlusal loading was assessed. (2) Methods: 15 patients were selected, the main inclusion criteria were the partially edentulous area in the posterior maxilla with alveolar bone height of less than 1.5 mm below the sinus. All of the patients underwent one-stage sinus lifting, along with simultaneous implant placement using a "butterfly" anchorage device to optimize the primary stability and xenograft bone as graft material. At 6 to 9 months after surgery, the anchorage device was removed and implants were loaded. Panoramic x-ray images were used to assess the new bone formation, while the biological stability was measured using resonance frequency analysis. (3) Results: 15 implants were inserted. The mean implant stability quotient (ISQ) value was 71.3 (SD = ±2.51) and the mean healing period was 7.3 (SD = ±1.23) months. The mean bone height after the healing period was 14.4 (SD = ±2.05). A statistically significant correlation was found between the healing period and the ISQ value (Spearman rho = 0.684, sig. = 0.005). No statistically significant correlation was found between the ISQ value and the new regenerated bone height (Person r = 0.389, sig. = 0.152). Smoking was identified as a risk factor involved in postoperative complications. (4) Conclusions: The results of the present preliminary study demonstrated that the proposed "butterfly" technique was effective when performing one-stage sinus lifting and simultaneous implant placement in cases with less than 1.5 mm of residual alveolar bone. The survival rate was 100% at 1-year post occlusal loading.

Vertical and horizontal ridge augmentation using customized CAD/CAM titanium mesh with versus without resorbable membranes. A randomized clinical trial.

OBJECTIVES: The aim was to evaluate the role of resorbable membranes applied over customized titanium meshes related to soft tissue healing and bone regeneration after vertical/horizontal bone augmentation. MATERIALS AND METHODS: Thirty patients with partial edentulism of the maxilla/mandible, with vertical/horizontal reabsorption of the alveolar bone, and needing implant-supported restorations, were randomly divided into two groups: Group A was treated using only custom-made meshes (Mesh-) and Group B using custom-made meshes with cross-linked collagen membranes (Mesh+). Data collection included surgical/technical and healing complications, "pseudo-periosteum" thickness, bone density, planned bone volume (PBV), regenerated bone volume (RBV), regeneration rate (RR), vertical bone gain (VBG), and implant survival in regenerated areas. Statistical analysis was performed between the two study groups using a significance level of α = .05. RESULTS: Regarding the healing complications, the noninferiority analysis proved to be inconclusive, despite the better results of group Mesh+ (13%) compared to group Mesh- (33%): estimated value -1.13 CI-95% from -0.44 to 0.17. Superiority approach confirmed the absence of significant differences (p = .39). RBV was 803.27 mm3 and 843.13 mm3 , respectively, and higher RR was observed in group Mesh+ (82.3%) compared to Mesh- (74.3%), although this value did not reach a statistical significance (p = .44). All 30 patients completed the study, receiving 71 implants; 68 out of them were clinically stable and in function. CONCLUSION: The results showed that customized meshes alone do not appear to be inferior to customized meshes covered by cross-linked collagen membranes in terms of healing complication rates and regeneration rates, although superior results were observed in group Mesh+compared to group Mesh- for all variables.

Mandibular reconstruction using a new design for a patient-specific plate to support a fibular free flap and avoid double-barrel technique.

Mandibular reconstruction is a primary concern for head and neck reconstructive surgeons because of the aesthetic restoration needs after ablative surgery, as well as for functional reasons: the mandible has a central functional role in speaking, swallowing and mastication. It is generally agreed that the gold standard for mandibular reconstruction is a bone free flap supported by a reconstructive titanium plate. The fibular flap represents the first choice for multi-segment mandibular reconstruction. The fibula, harvested as a single barrel graft, does not exhibit sufficient thickness to reach the original height of the native mandible; therefore, the positioning of dental implants is often deeper than that of the native alveolar crest. The aim of this study was to evaluate the positioning of the fibular free flap as it pertains to the restoration of vertical mandible height, by modifying the design of a 3D-printed titanium patient-specific implant (PSI). In this novel reconstructive workflow, the customised plate was projected to support the fibular flap at an alveolar bone position above the typical inferior mandibular border, and carried out on four patients. All patients were treated for benign neoplasms involving mandibular bone. Clinical outcomes and accuracy of the procedure are described. Our reconstructive proposal appears to be a valid alternative to the double-barrel technique in order to restore the vertical height of the reconstructed mandible.^ieng

La ricostruzione mandibolare è particolarmente rilevante per il chirurgo cervico-cefalico, in quanto influenza significativamente i successi in termini di risultati estetici e funzionali per il paziente. Il gold standard per tale ricostruzione è l'utilizzo di lembi ossei rivascolarizzati, stabilizzati mediante una placca ricostruttiva in titanio. Il lembo di fibula rappresenta la prima scelta ricostruttiva laddove necessitino molteplici segmenti ossei. Tuttavia questo lembo, allestito secondo la tecnica della singola barra, non permette di ripristinare l'altezza mandibolare nativa, adeguata per una corretta riabilitazione masticatoria implanto-supportata. Lo scopo di questo studio è quindi presentare un nuovo design di placca ricostruttiva custom-made, atta a posizionare il segmento osseo di fibula in una posizione più coronale, evitando pertanto la necessità di allestire il lembo secondo la tecnica della doppia barra. La placca custom-made contribuisce inoltre al mantenimento del profilo mandibolare, garantendo il ripristino morfologico della ricostruzione. Questo protocollo è stato eseguito su quattro pazienti sottoposti a resezione mandibolare per tumori benigni. I risultati clinici e di accuratezza della procedura sono presentati. Il protocollo presentato sembra una valida alternativa alla tecnica della doppia barra al fine di ripristinare l'altezza mandibolare nativa.

A microcomputed tomography analysis of bone tissue after vertical ridge augmentation with non-resorbable membranes versus resorbable membranes and titanium mesh in humans.

PURPOSE: Guided bone regeneration is a frequently used surgical procedure for hard tissue reconstruction when horizontal and or/vertical augmentation are needed. The treatment concept is based on the application of occlusive membranes like non-resorbable membranes or titanium mesh plus resorbable membranes. However, there are no studies comparing the microcomputed tomography results for bone obtained using these two procedures, and this was the purpose of the present study. MATERIALS AND METHODS: A total of 40 patients with vertical posterior bone mandibular atrophy were randomly assigned to group A (guided bone regeneration with titanium-reinforced polytetrafluoroethylene membrane and simultaneous implant placement) or group B (guided bone regeneration with titanium mesh and collagen membrane and simultaneous implant placement). Tissue biopsy specimens were obtained from augmented sites after 9 months for microcomputed tomography analysis of volume of interest. Bone volume (BV/TV), biomaterial volume (MatV/TV), soft tissue volume (StV/TV), trabecular thickness (TbTh), trabecular number (TbN) and trabecular separation (TbSp) were measured. The correlation between regenerated bone and native bone was also evaluated. STATA software (StataCorp, College Station, TX, USA) was utilised for statistical analysis (significance α = 0.05). RESULTS: In group A, the values of BV/TV, MatV/TV and StV/TV in regenerated bone were 28.8%, 8.9% and 62.4%, respectively. In group B, the values of BV/TV, MatV/TV and StV/TV were 30.0%, 11.0% and 59.0%, respectively. No statistical differences were found between the two groups for any of the variables (P < 0.05). In both groups, considerable differences were noted between regenerated and native bone (P > 0.05), with a slight correlation between the microcomputed tomography parameters that suggests that native bone influences the quality of regenerated bone. CONCLUSIONS: Based on microcomputed tomography analysis, both surgical approaches facilitated the obtention of approximately 30% of newly formed bone with the same microarchitecture. Native bone influences the quality and microarchitecture of the obtained bone, irrespective of the technique used.

Vertical ridge augmentation (VRA) with Ti-reinforced d-PTFE membranes or Ti meshes and collagen membranes: 1-year results of a randomized clinical trial.

OBJECTIVES: The aim of this study was to evaluate hard and soft tissues around implants placed in posterior mandible 1 year after vertical ridge augmentation (VRA). MATERIALS AND METHODS: 40 patients with vertical defects were enrolled and treated according to the study protocol. Patients were randomly divided into two study groups: reinforced PTFE membranes (group A) and titanium meshes plus collagen membranes (group B). All patients received simultaneous implants which were evaluated after prosthetic restoration at baseline and after 1 year, using the following parameters: peri-implant bone levels (PBLs), interproximal bone peaks (IBPs), pocket probing depth (PPD), bleeding on probing (BoP), plaque index (mPI), gingival index (mGI), keratinized tissue thickness/width (tKT and wKT), and fornix depth (FD). Statistical analysis was performed to investigate any statistically significant differences and/or correlations (p = .05). RESULTS: 30 patients were completely followed up according to the study protocol. After 1 year, implants showed a change in PBL from 0.12 to 0.76 mm, with marginal bone loss of 0.67 and 0.61 mm for group A and group B, respectively, without significant differences (p > .9337). The estimated difference between treatments for the change from baseline in PBL was -0.05 (95% CI -0.27 to 0.16). Statistical analysis revealed strong correlations between PBL and IBP (p < .0001). However, no significant differences were observed for PPD, mPI, mGI, tKT, wKT, and FD (p > .05). CONCLUSION: The results indicate that GBR treatment with titanium meshes plus collagen membranes (Group B) compared to reinforced PTFE membranes does not appear to be inferior or superior in terms of PBL change. In both groups, hard and soft tissues were stable after 1 year of follow-up, with a peri-implant bone loss less than 1.0 mm in the first year (study registered at ClinicalTrials.gov NCT04332679).

Clinical and volumetric outcomes after vertical ridge augmentation using computer-aided-design/computer-aided manufacturing (CAD/CAM) customized titanium meshes: a pilot study.

BACKGROUND: One of the most recent innovations in bone augmentation surgery is represented by computer-aided-design/computer-aided-manufacturing (CAD/CAM) customized titanium meshes, which can be used to restore vertical bone defects before implant-prosthetic rehabilitations. The aim of this study was to evaluate the effectiveness/reliability of this technique in a consecutive series of cases. METHODS: Ten patients in need of bone augmentation before implant therapy were treated using CAD/CAM customized titanium meshes. A digital workflow was adopted to design virtual meshes on 3D bone models. Then, Direct Metal Laser Sintering (DMLS) technology was used to produce the titanium meshes, and vertical ridge augmentation was performed according to an established surgical protocol. Surgical complications, healing complications, vertical bone gain (VBG), planned bone volume (PBV), lacking bone volume (LBV), regenerated bone volume (RBV), average regeneration rate (RR) and implant success rate were evaluated. RESULTS: All augmented sites were successfully restored with definitive implant-supported fixed partial dentures. Measurements showed an average VBG of 4.5 ± 1.8 mm at surgical re-entry. Surgical and healing complications occurred in 30% and 10% of cases, respectively. Mean values of PBV, LBV, and RBV were 984, 92, and 892 mm3, respectively. The average RR achieved was 89%. All 26 implants were successfully in function after 1 year of follow-up. CONCLUSIONS: The results of this study suggest that the bone augmentation by means of DMLS custom-made titanium meshes can be considered a reliable and effective technique in restoring vertical bone defects.

Evaluation of Crestal Bone Loss Around Straight and Tilted Implants in Patients Rehabilitated by Immediate-Loaded Full-Arch All-on-4 or All-on-6: A Prospective Study.

The aim of this prospective study was to compare implant success rate and crestal bone loss around tilted and straight implants supporting immediate-loading full-arch rehabilitations. Twenty consecutive patients with edentulous jaws treated between June 2013 and July 2015 who satisfied all inclusion and exclusion criteria were included in the study. All patients were rehabilitated through a full-arch restoration supported by 4 or 6 immediately loaded implants. Clinical and radiographic examinations were scheduled every 12 months to evaluate implant success rates and crestal bone levels. Significant differences in crestal bone levels and success rates between straight and tilted implants were investigated by means of independent statistical analysis; differences were regarded as significant if P < .05. Seventy straight and 50 tilted implants were placed to rehabilitate 14 mandibles and 12 maxillae in 20 patients. After a follow-up of 12 to 36 months, survival rate was 97.1% for straight implants and 96.0% for tilted implants; while success rates were 94.3% and 94.0%, respectively. Success and survival rates were not significantly different (P > .05). Change in crestal bone level was 0.5 ± 0.4 mm for straight implants and 0.6 ± 0.4 mm for tilted implants (P > .05). Straight and tilted implants seemed to have similar behavior after immediate loading rehabilitations. After functional loading, straight and tilted implants did not differ significantly in clinical outcome.

Histological and histomorphometric analysis of bone tissue after guided bone regeneration with non-resorbable membranes vs resorbable membranes and titanium mesh.

BACKGROUND: Guided bone regeneration (GBR) allows to achieve vertical ridge augmentation whether with nonresorbable membranes or resorbable membranes with Ti-mesh, but till now no studies are published comparing histological and histomorphometrical outcomes of these two procedures. MATERIALS AND METHODS: Forty partially edentulous patients required vertical bone regeneration to place implants in the posterior mandible: 20 patients were randomly assigned to group A (Ti-PTFE); while 20 patients to group B (Collagen plus Ti-mesh). For both groups, graft material was a 50:50 mixture of autogenous bone and bone allograft. After 9 months, tissue biopsies were taken from augmented sites (regenerated bone ROI-1; native bone ROI-2) and undergone to histological and histomorphometric analysis. Percentages of bone tissue (B.Ar), biomaterial (Mat. Ar), and soft tissue (St.Ar) were measured; measurements of perimeters were calculated too. ROI-1 values were also compared to ROI-2 in both groups. RESULTS: Twenty-five samples were collected and analyzed consecutively: 13 in group A and 12 in group B. The mean B.Ar, Mat.Ar, and St.Ar were 39.7%, 8.6%, and 52.1% in group A; similar results were obtained in group B, with mean values of 42.1%, 9.6%, and 48.3%, respectively. No significant statistically differences were observed. Differences were observed between ROI-1 and ROI-2 in both group. Finally, bone structure index of ROI-1 and ROI-2 showed statistical differences. CONCLUSIONS: The preliminary results of this study suggest that GBR using nonresorbable membranes and Ti-mesh with resorbable membranes in combination with autogenous bone and bone allograft provide similar histological and histomorphometric results.

A Proposal of Pseudo-periosteum Classification After GBR by Means of Titanium-Reinforced d-PTFE Membranes or Titanium Meshes Plus Cross-Linked Collagen Membranes.

After guided bone regeneration (GBR) with different devices, a layer of connective tissue called pseudo-periosteum can be observed above the newly formed bone. The aim of this study is to evaluate the clinical and histologic features and to suggest a classification of this connective tissue after GBR with nonresorbable membranes or titanium (Ti)-mesh plus resorbable membranes. Forty patients with partial edentulism in the posterior mandible were randomized into two groups: 20 patients were treated by means of Ti-reinforced dense polytetrafluoroethylene (d-PTFE) membrane (group A), while the other 20 patients were treated with Ti-mesh and a cross-linked collagen membrane (group B). After 9 months and during re-opening surgery, bone density and pseudo-periosteum type were recorded. Pseudo-periosteum was classified into Type 1 (no tissue or tissue < 1 mm); Type 2 (regular tissue between 1 and 2 mm); and Type 3 (irregular tissue or tissue > 2 mm). Histologic analyses were performed to identify the features of pseudo-periosteum. Out of 40 patients, 36 (n = 19 in Group A; n = 17 in Group B) with 99 implants were analyzed after GBR and according to the study protocol. The vertical bone gain was 4.2 ± 1.0 mm in Group A and 4.1 ± 1.0 mm in Group B. Group A had a higher bone density and greater amounts of type 1 periosteum than Group B (P = .01 for both). The preliminary results of this study show that both d-PTFE membranes and Ti-mesh plus collagen membranes are two valid options for bone augmentation in the mandible. However, nonresorbable membranes achieve higher bone density and a thinner pseudo-periosteum layer above the newly formed bone.

Coronectomy: A Surgical Option for Impacted Third Molars in Close Proximity to the Inferior Alveolar Nerve-A 5-Year Follow-Up Study.

PURPOSE: The extraction of third molars is the most common surgical procedure performed in the oral cavity. Coronectomy is a surgical protocol to reduce the risk of neurologic lesions to the inferior alveolar nerve (IAN). We evaluated early (up to 1 month) and late (from 2 to 60 months) postoperative complications. MATERIALS AND METHODS: This prospective cohort study enrolled patients treated at the Unit of Oral and Maxillofacial Surgery, University of Bologna. The predictor variable was the time after coronectomy with up to 5 years' follow-up. To assess the rate of postoperative complications, the outcome variables were neurologic injuries, postoperative pain, swelling, fever, alveolitis, pulpitis, and root exposure. The success rate, need for a second surgical procedure, probing pocket depth, and bleeding on probing also were investigated. Univariate and bivariate descriptive statistics, Kaplan-Meier analysis, and Cox hazards modeling were performed to evaluate the variables. RESULTS: We performed 116 coronectomies in 94 healthy patients (37 men and 57 women; mean age, 28.99 ± 8.9 years). At 5 years' follow-up, we re-evaluated 63 patients with 76 coronectomies. In total, 30 complications were verified. No cases of neurologic lesions to the IAN or lingual nerve were observed after surgery. In the first 3 years, the surgeons extracted migrated roots in 5 cases (6%) without any neurologic lesions to the IAN. No complications were observed from the third to fifth year. CONCLUSIONS: This prospective study on coronectomy of third molars in a close relationship with the mandibular canal found no cases of neurologic lesions, no cases of late infection of the retained roots at 5 years, and a low rate of immediate postoperative complications. Further investigations should include a follow-up study at 10 years and more research about the mechanism of pulp healing.

Stability of Periodontal Healing Distal to the Mandibular Second Molar After Third Molar Coronectomy: A 3-Year Follow-Up Study.

PURPOSE: The stability of the periodontal attachment distal to the mandibular second molar after coronectomy of the third molar is still unclear. This study addressed the question of whether periodontal measures are stable over time among patients undergoing coronectomy. MATERIALS AND METHODS: This prospective cohort study enrolled 30 patients treated at the Unit of Oral and Maxillofacial Surgery of the University of Bologna. The predictor variables were the probing pocket depth (PPD), distance between the marginal crest and the bottom of the osseous defect (BOD), and distance between the cementoenamel junction and the BOD. Three points on the distal surface of the second molar were recorded: distobuccal, distomedial, and distolingual sites. The distobuccal site was used as the statistical unit. The Wilcoxon test for paired data and Kendall τb were used to evaluate all variables. The significance level was set at P < .05. RESULTS: The 3-year follow-up was completed by 27 patients (7 male and 20 female patients; mean age, 28 ± 7 years) with 30 third molars. At 3 years, the PPD was 4 ± 1.25 mm; no significant changes in PPD were recorded for all sites from 9 months to 3 years. For the marginal crest-BOD distance and the cementoenamel junction-BOD distance, significant reductions were evident between preoperative values and those at 9 to 36 months (P = .001) and between values at 9 and 36 months (P = .02). CONCLUSIONS: A clinical healthy periodontium distal to the second molar was observed 36 months after coronectomy. However, further studies are necessary to confirm these preliminary clinical results.

Long-term results of osseointegrated implant-based dental rehabilitation in oncology patients reconstructed with a fibula free flap.

BACKGROUND: Dental rehabilitation with conventional prostheses after microvascular jaw reconstruction is often unsuccessful because of the altered oral anatomy and the lack of adequate dentition for fixation. PURPOSE: This retrospective study evaluated the long-term outcomes of patients who underwent jaws reconstruction with a fibula free flap and subsequent rehabilitation with implant-supported prostheses. MATERIALS AND METHODS: In total, 21 patients were enrolled; 108 osseointegrated dental implants, positioned on 21 fibular free flaps were assessed. Follow-up examinations were performed according to a standardized protocol, including clinical and radiological evaluations. The mean follow-up after implant insertion was 90.2 (range, 20-204) months. RESULTS: The overall implant survival rate was 97.2% at the 12-month follow-up, 86.5% at 60 months, and 79.3% at 120 months. The rate of overall implant success was 95.4% at the 12-month follow-up, 73.5% at 60 months, and 64.7% at 120 months. Implant failure was more common in patients that had implants placed after they underwent radiation therapy. Peri-implantitis and mucositis were identified in 14.8% and 20.3% of surviving implants, respectively, at the 5- and 10-year follow-up. The risk of developing peri-implantitis was estimated to be higher (odds ratio = 1.5) for patients without connective tissue or skin grafts versus patients with one of them (18.2% vs 9.5%). CONCLUSIONS: Long-term implant-related outcomes show that the survival rate of implants placed into the fibula is acceptable. Radiotherapy negatively impacts survival and success, in particular in the short and medium-term follow-up. Moreover, a relevant peri-implant bone resorption does occur over time and ultimately influences implants success, and it is mainly related to peri-implant gingival mucositis. In this regard skin or connective tissue grafts seem to offer an aid to manage this problem.