Factors influencing outcomes of surgical therapy of peri-implantitis: A secondary analysis of 1-year results from a randomized clinical study.

AIM: To identify predictors of treatment outcomes following surgical therapy of peri-implantitis. MATERIALS AND METHODS: We performed a secondary analysis of data from a randomized controlled trial (RCT) comparing access flap with or without bone replacement graft. Outcomes at 12 months were probing pocket depth (PPD), bleeding on probing (BOP), soft-tissue recession (REC) and marginal bone level (MBL) change. Multilevel regression analyses were used to identify predictors. We also built an explanatory model for residual signs of inflammation. RESULTS: Baseline PPD was the most relevant predictor, showing positive associations with final PPD, REC and MBL gain, and negative association with probability of pocket closure. Smokers presented higher residual PPD. Absence of keratinized mucosa at baseline increased the probability of BOP but was otherwise not indicative of outcomes. Plaque at 6 weeks was detrimental in terms of residual PPD and BOP. Treatment allocation had an effect on REC. Final BOP was explained by residual PPD ≥6 mm and plaque at more than two sites. CONCLUSIONS: Baseline PPD was the most relevant predictor of the outcomes of surgical therapy of peri-implantitis. Pocket closure should be a primary goal of treatment. Bone replacement grafts may be indicated in aesthetically demanding cases to reduce soft-tissue recession. The importance of smoking cessation and patient-performed plaque control is also underlined.

Influence of soft tissue thickness on marginal bone level around dental implants: A systematic review with meta-analysis and trial-sequential analysis.

OBJECTIVES: The aim of the present review and meta-analysis was to evaluate the influence of soft tissue thickness on initial bone remodeling after implant installation. MATERIALS AND METHODS: A literature search was conducted by two independent reviewers on electronic databases up to May 2022. Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) performed on human subjects were included. The risk of bias was evaluated using Cochrane Collaboration's tool. Meta-analysis and Trial Sequential Analysis (TSA) were performed on the selected articles. The primary outcome was marginal bone loss. RESULTS: After screening, 6 studies were included in the final analysis, with a total of 354 implants, and a follow-up from 10 to 14 months. 194 implants were placed in a ≥ 2 mm soft tissue thickness, while 160 had <2 mm soft tissue thickness before implant placement. The included studies had a high level of heterogeneity (I2  > 50%). The meta-analysis indicated a statistically significant difference between the two groups (0.54; p = .027) and the TSA analysis confirmed the results, despite the limited number of dental implants. Additional analysis showed that age and follow-up parameters were not statistically significant factors influencing the bone loss (p = .22 and p = .16, respectively). CONCLUSIONS: Based on the available RCTS and CCTs, initial soft tissue thickness seems to influence marginal bone loss after a short follow-up period. Based on TSA analysis, further studies are needed to assess the influence of the soft tissue thickness on marginal bone loss. PROSPERO registration number: CRD42021235324.

Reconstructive surgical therapy of peri-implantitis: A multicenter randomized controlled clinical trial.

OBJECTIVE: To evaluate the potential benefit of the use of a bone substitute material in the reconstructive surgical therapy of peri-implantitis. METHODS: In this multicenter randomized clinical trial, 138 patients (147 implants) with peri-implantitis were treated surgically, randomized by coin toss to either a control (access flap surgery) or a test group (reconstructive surgery using bone substitute material). Clinical assessments, including probing pocket depth (PPD), bleeding and suppuration on probing (BOP & SOP) as well as soft tissue recession (REC), were recorded at baseline, 6 and 12 months. Marginal bone levels (MBL), measured on intra-oral radiographs, and patient-reported outcomes (PROs) were recorded at baseline and 12 months. No blinding to group allocation was performed. The primary outcome at 12 months was a composite measure including (i) implant not lost, (ii) absence of BOP/SOP at all aspects, (iii) PPD ≤5 mm at all aspects and (iv) ≤1 mm recession of mucosal margin on the buccal aspect of the implant. Secondary outcomes included (i) changes of MBL, (ii) changes of PPD, BOP%, and buccal KM, (iii) buccal REC and (iv) patient-reported outcomes. RESULTS: During follow-up, four implants (one in the test group, three in the control group) in four patients were removed due to disease progression. At 12 months, a total of 69 implants in the test and 68 implants in the control group were examined. Thus, 16.4% and 13.5% of implants in the test and control group, respectively, met all predefined criteria of the composite outcome. PPD reduction and MBL gain were 3.7 mm and about 1.0 mm in both groups. Reduction in mean BOP% varied between 45% (test) and 50% (control), without significant differences between groups. Buccal REC was less pronounced in the test group (M = 0.7, SD = 0.9 mm) when compared to controls (M = 1.1, SD = 1.5 mm). PROs were favorable in both groups without significant differences. One case of allergic reaction to the antibiotic therapy was recorded. No other adverse events were noted. CONCLUSIONS: Surgical therapy of peri-implantitis effectively improved the clinical and radiographic status at 12 months. While the use of a bone substitute material did not improve reductions of PPD and BOP, buccal REC was less pronounced in the test group. Patient satisfaction was high in both groups.

Patients' perceptions of implant therapy and maintenance: A questionnaire-based survey.

OBJECTIVES: To evaluate patients' perceptions regarding implant treatment and maintenance. MATERIAL AND METHODS: A semi-structured questionnaire was developed focusing on 4 main domains: (a) information regarding possible complications received before implant therapy; (b) information received after treatment regarding maintenance; (c) self-performed daily home care; and (d) implant maintenance received at the dental office. Adult patients, restored with implant-supported prosthesis by at least 6 months, were recruited between June 2016 and December 2017. RESULTS: The study population consisted of 522 patients with a mean age of 61 years. The majority of the participants referred to have received information about the need of periodical check-ups (91.6%). However, only 58.9% declared to have been informed about complications and failures before treatment commencement. Even though 91.2% of the participants declared to have received instruction about cleaning measures around implants, less than half of the sample reported to have been asked to try the cleaning tools at the office (40.4%). Even though patients' awareness about implant treatment and maintenance resulted to be low in a consistent part of the sample, patients' satisfaction level about information received regarding implant care was high (Visual Analogue Scale 8.18). CONCLUSIONS: Most patients appeared to be informed about the importance of specific oral hygiene measurements and recall programs. However, an unsatisfactory level of knowledge about implant-related complications was evidenced. Improvements in time and energy employed by dentists and hygienist in communication with patients are needed, in order to enhance health outcomes and compliance both to the treatment and to the maintenance.

Evaluation and comparison of histologic changes and implant survival in extraction sites immediately grafted with two different xenografts: A randomized clinical pilot study.

OBJECTIVES: The purpose of this prospective, single-center randomized pilot study was to histologically evaluate and compare vital bone development in premolar and molar-extraction sites grafted with two different bovine-derived xenografts. The secondary outcome of interest was implant survival in the grafted sites. MATERIALS AND METHODS: Adult patients in need of at least two tooth extractions were enrolled. A paired design was used; each patient received at least one of each type of graft at different sites. Each extraction site was randomized to one of two xenograft treatment groups. A resorbable membrane was always placed, and primary intention soft tissue closure was achieved. Four months later, implants were placed and a trephine drill was used to remove bone cores for histologic and histomorphometric analysis. RESULTS: Sixteen patients with 40 extraction sites were enrolled; 20 sites were grafted with one type of xenograft and 20 with another. Mean patient age was 53.5 years, and 65% of patients were male. Evaluation of bone core samples taken from grafted sites showed no significant difference in the mean value of percentage of new bone formation between the different grafted sites (33.4% and 32.4%, p = .76). Cumulative implant survival was 97.5% at the 24-month follow-up visit. CONCLUSION: Within the limitations of this pilot study, no statistically significant differences in new bone growth between sites grafted with two different types of xenograft were found. Both graft materials promoted the formation of new bone and provided osseous support for implant placement after socket grafting.

Influence of abutment material on peri-implant soft tissues in anterior areas with thin gingival biotype: a multicentric prospective study.

PURPOSE: The aim of the present clinical trial was to analyze, through spectrophotometric digital technology, the influence of the abutment material on the color of the peri-implant soft tissue in patients with thin gingival biotype. MATERIAL AND METHODS: Thirty-seven patients received an endosseous dental implant in the anterior maxilla. At time of each definitive prosthesis delivery, an all-ceramic crown has been tried on gold, titanium and zirconia abutment. Peri-implant soft-tissue color has been measured through a spectrophotometer after the insertion of each single abutment. Also facial peri-implant soft-tissue thickness was measured at the level of the implant neck through a caliper. A specific software has been utilized to identify a standardized tissue area and to collect the data before the statistical analysis in Lab* color space. ΔE parameters of the selected abutments were tested for correlation with mucosal thickness. Pearson correlation test was used. RESULTS: Only 15 patients met the study inclusion criteria on peri-implant soft-tissue thickness. Peri-implant soft-tissue color was different from that around natural teeth, no matter which type of restorative material was selected. Measurements regarding all the abutments were above the critical threshold of ΔE 8.74 for intraoral color distinction by the naked eye. The ΔE mean values of gold and zirconium abutments were similar (11.43 and 11.37, respectively) and significantly lower (P = 0.03 and P = 0.04, respectively) than the titanium abutment (13.55). In patients with a facial soft-tissue thickness ≤2 mm, the ΔE mean value of gold and zirconia abutments was significantly lower than that of titanium abutments (P = 0.03 and P = 0.04, respectively) and much more close to the reference threshold of 8.74. CONCLUSIONS: For peri-implant soft tissue of ≤2 mm, gold or zirconia abutments could be selected in anterior areas treatment. Moreover, the thickness of the peri-implant soft tissue seemed to be a crucial factor in the abutment impact on the color of soft tissues with a thickness of ≤2 mm.

Microbial Leakage at Morse Taper Conometric Prosthetic Connection: An In Vitro Investigation.

OBJECTIVE: To evaluate in vitro the sealing capability at the prosthetic connection interface of 2 conometric systems. MATERIALS AND METHODS: Two conometric systems with the same design and different material were used, for a total of 24 samples. Each sample was assembled by a tapered abutment and respective coping. In group A, the copings were made of gold, whereas in group B they were made of PEEK. Three µL of mix bacterial suspension (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Fusobacterium nucleatum species) was inoculated into the abutment screw hole, and the coping was inserted on the abutment. Samples were immersed into culture tubes and incubated for 24, 48, and 72 hours into anaerobic conditions. Visual evaluation of turbidity was performed at each time point. Qualitative-quantitative assessment using real-time polymerase chain reaction was performed at 72 hours. Any difference between the groups was checked by means of Fisher exact test. RESULTS: Microbial leakage occurred in both groups, and there was no statistically significant difference between groups. Microbial concentration resulted in a presence inferior to 1 × 10 copies/µL in all positive assemblies. CONCLUSIONS: Because of the low bacterial count, it can be concluded that a minimal bacterial infiltration may be allowed by conometric interfaces for prosthetic connection.

Ridge Dimensions of the Edentulous Mandible in Posterior Sextants: An Observational Study on Cone Beam Computed Tomography Radiographs.

AIMS: To evaluate the ridge dimensions of posterior sextant in totally edentulous mandibles. MATERIAL AND METHODS: Cone beam computed tomography scans of 136 patients were retrospectively included for analysis. At sites corresponding to the second premolar (site a) and the mesial and distal root of first molar (sites b and c, respectively), bone height (BH) and bone width (BW) were measured. RESULTS: BH significantly decreased from site a (11.20 ± 4.03 mm) to site c (10.28 ± 3.33 mm). Males showed a significantly higher BH compared with females at all sites (P < 0.001), No significant impact of age on BH was found. BW increased from coronal to apical at all sites. At all height levels, BW increased from mesial to distal (BWc > BWb > BWa). CONCLUSIONS: BH decreased from mesial to distal, whereas BW showed an increase. Sex showed a significant impact on BH, with males having on average a 2.8 mm greater height than females, but not on BW. Age did not significantly influence the dimensions of the residual bone crest.

Patient morbidity and root coverage outcomes after the application of a subepithelial connective tissue graft in combination with a coronally advanced flap or via a tunneling technique: a randomized controlled clinical trial.

BACKGROUND AND OBJECTIVE: Subepithelial connective tissue grafts (SeCTG) in conjunction with a coronally advanced flap (CAF) or with tunneling technique (TT) are common periodontal procedures with similar indications for the treatment of a denuded root surface; however, it is unclear whether patient discomfort and postoperative morbidity are comparable in both approaches. The aim of this randomized controlled clinical trial was to compare the patient morbidity and root coverage outcomes of a SeCTG used in combination with a CAF or TT. MATERIALS AND METHODS: For this single-center, randomized, clinical trial, patients were randomly assigned to receive SeCTG + CAF (control group) or SeCTG + TT (test group). Postoperative questionnaires at 3 days post intervention were administered to evaluate postoperative discomfort, bleeding, and inability to masticate. Evaluation of patients' perception of pain was performed using a visual analog scale (VAS). Clinical outcomes including percentage of root coverage (RC) and complete root coverage (CRC) were recorded 12 months postoperatively. RESULTS: Fifty patients (25 SeCTG + CAF and 25 SeCTG + TT) completed the study. Healing was uneventful for all test and control patients. The SeCTG + TT group showed a longer chair time (33.6 (3.6) and 23.6 (4.2) min for the SeCTG + TT and the SeCTG + CAF, respectively), as well as more painkiller consumption: 2736 vs. 1536 mg (p < 0.001). At the same time, the SeCTG + CAF group reported less pain or discomfort in all four sections of the questionnaire: pain experienced within the mouth as a whole, pain experienced throughout the day, pain experienced at night, and edema experienced after the surgery (p = 0.002, p = 0.001, p = 0.001, and p = 0001, respectively). Both treatments showed clinical efficacy in terms of root coverage as no differences per group were observed in the percentage of root coverage (87 vs. 85 %, p = 704) or patients with complete root coverage (60 vs. 52 %, p = 0.569). CONCLUSIONS: SeCTG + TT is associated with a greater incidence of pain and discomfort compared to SeCTG + CAF in early postoperative periods, as well as a longer chair time. Both treatments showed similar clinical efficacy in terms of root coverage. CLINICAL RELEVANCE: The results of this study may influence the surgeon's choice on which root coverage procedure should be performed considering the need of more chair time and more painkiller assumption with the tunneling technique.

Reproducibility of Buccal Gingival Profile Using a Custom Pick-Up Impression Technique: A 2-Year Prospective Multicenter Study.

PURPOSE: The aim of this study was to transfer the provisional restoration emergence profile to the final implant-supported restoration and to buccal gingival margin (BGM) stability after 2 years of function. MATERIALS AND METHODS: A total of 33 patients were recruited for treatment of single gaps by means of 33 implant-supported restorations. Fixed provisional crowns were screwed to the fixture and adjusted until the complete peri-implant soft tissue maturation was achieved. After 12 weeks, a second fixture impression was taken by means of a pick-up customization technique in order to transfer the clinical aspect of the peri-implant soft tissues to the master cast. A definitive restoration was delivered. A standardized method from digital photographs was used to assess the gingival margin modification (BGM) from the provisional (P) to the definitive prosthesis installation at baseline (D0), and after 1 (D1) and 2 years (D2) of function. Also, marginal bone loss (MBL) was calculated after 1 (D1) and 2 years (D2) of definitive restoration function. RESULTS: The BGM index at the time of the final restoration installation (D0) was 0.12 ± 0.33 mm if compared with the BGM position of the provisional restoration (P); it was of 0.12 ± 0.46 mm after 1-year of follow-up (D1) and of 0.31 ± 0.21 after 2 years of function (D2). No significant difference was calculated between measurements in different follow-up visits (p > 0.05). No significant MBL was measured between the baseline (D0) and the 1-year follow-up (p = 0.816) with a mean MBL value of 0.2 ± 0.1 mm. Similar result was calculated after 2 years (p = 0.684) with a mean MBL value of 0.3 ± 0.2. CONCLUSION: A modified impression pick-up may be helpful to reproduce the gingival margin position from the provisional to the definitive restoration. Moreover, the gingival zenith position during the follow-up period seemed to be stable. CLINICAL SIGNIFICANCE: The modification of the standard impression pick-up technique may contribute to reproducing a natural emergence profile of esthetic implant prosthetic restorations (from the provisional to the definitive restoration.) With this technique, implant soft tissues stability around CAD-CAM (computer aided design-computer aided manufacturing) abutments can be easily obtained, and the customized abutment shape may better support the scalloped peri-implant soft tissues architecture, especially in anterior areas.

Soft tissues stability of cad-cam and stock abutments in anterior regions: 2-year prospective multicentric cohort study.

AIM: Aim of this study was to verify if the type of implant abutment manufacturing, stock or cad-cam, could influence the maintenance of stable gingival margins around single restorations in anterior areas. METHODS: After 16 weeks of healing, implants (Osseospeed, Astra Tech Dental Implant) were positioned. Depending on the different fixture inclination and the thickness of buccal peri-implant soft tissue, abutment selection resulted in four groups: Group 1 (patients with zirconia ZirDesign(®) stock abutments), Group 2 (titanium stock TiDesign(®) abutments), Group 3 (zirconia cad-cam abutments), and Group 4 (titanium cad-cam abutments). The following parameters were assessed: buccal gingival margin modification (BGM). The modification of the implant gingival margin was followed at 1 and 2 years of follow-up. A computerized analysis was performed for measurements. Differences between soft tissue margin at baseline and after 2 years measured the gingival margin recession. A general linear model was used to evaluate each group in relation to gingival recession after two years. Tukey's post hoc test was used to compare the mean REC indexes of each group of abutments. RESULTS: Seventy-two healthy patients (39 males and 33 females; mean age of 46 years) scheduled for single gap rehabilitation in anterior areas were enrolled. A 100% of implant survival rate was observed after 24 months of function. One failure occurred due to fracture of a Zirconia cad-cam abutment. Moreover, two abutment screw unscrewing were observed. Both for zirconia and titanium stock abutments (Group 1 and 2), the mean recession of implant buccal soft tissue was of 0.3 mm (SD of 0.3 and 0.4 mm, respectively). Soft tissue mean recession of zirconia and titanium cad-cam abutments (Group 3 and 4) was of 0.1 and -0.3 mm, respectively (SD of 0.3 and 0.4 mm, respectively). REC values of cad-cam titanium abutments (Group 4) were significantly lower than that of Group 1 (-0.57 mm), Group 2 (-0.61 mm), and Group 3 (-0.40 mm), respectively (Table 4). CONCLUSION: In the anterior area, the use of cad-cam abutments is related to a better soft tissue stability. Such a relationship is significant if cad-cam titanium abutments are compared to both titanium and zirconia stock abutments.

Dimensions of the healthy gingiva and peri-implant mucosa.

OBJECTIVE: To determine the dimensions of the soft tissue cuff present at various aspects of teeth and to compare these dimensions to those of the mucosa surrounding single implants. MATERIAL AND METHODS: Fifty volunteers were recruited that were ≥25 years of age and exhibited no signs of (i) untreated caries; (ii) loss of periodontal tissue support in the incisor, canine, and premolar regions; (iii) systemic or local disease. Furthermore, among the 50 patients recruited (iV), 27 had one single implant in the maxilla with teeth present mesial and/or distal to the implant. Probing pocket depth (PPD) and transmucosal sounding depth (TS) were assessed by five experienced, carefully calibrated examiners and with the use of a periodontal probe at the proximal (mesial, distal) and flat (facial, buccal and palatal/lingual) surfaces of all teeth/implants. The width of the keratinized mucosa (KM) was also determined. RESULTS: It was demonstrated that (i) PPD and TS were greater at proximal than at flat surfaces at both tooth and implant sites. In addition, both PPD and TS were deeper at implant than at tooth sites. The TS values documented that the cuff of healthy soft tissue that surrounded a tooth varied between 2 mm at flat surfaces and 4 mm at proximal surfaces, while at implant sites, the mucosa at proximal as well as flat surfaces was 1-1.5 mm greater. CONCLUSION: The probing pocket depth (PPD) and the transmucosal sounding depth (TS) values were greater at proximal than at flat, that is, facial/palatal (lingual) surfaces at tooth sites and frequently also at implant sites. Furthermore, the PPD and the TS dimensions were greater at implant than at adjacent tooth sites.

A hyaluronan-based scaffold for the in vitro construction of dental pulp-like tissue.

Dental pulp tissue supports the vitality of the tooth, but it is particularly vulnerable to external insults, such as mechanical trauma, chemical irritation or microbial invasion, which can lead to tissue necrosis. In the present work, we present an endodontic regeneration method based on the use of a tridimensional (3D) hyaluronan scaffold and human dental pulp stem cells (DPSCs) to produce a functional dental pulp-like tissue in vitro. An enriched population of DPSCs was seeded onto hyaluronan-based non-woven meshes in the presence of differentiation factors to induce the commitment of stem cells to neuronal, glial, endothelial and osteogenic phenotypes. In vitro experiments, among which were gene expression profiling and immunofluorescence (IF) staining, proved the commitment of DPSCs to the main components of dental pulp tissue. In particular, the hyaluronan-DPSCs construct showed a dental pulp-like morphology consisting of several specialized cells growing inside the hyaluronan fibers. Furthermore, these constructs were implanted into rat calvarial critical-size defects. Histological analyses and gene expression profiling performed on hyaluronan-DPSCs grafts showed the regeneration of osteodentin-like tissue. Altogether, these data suggest the regenerative potential of the hyaluronan-DPSC engineered tissue.

Conometric retention for complete fixed prosthesis supported by four implants: 2-years prospective study.

OBJECTIVE: The aim of this study was to verify the reliability of a conometric system for a fixed retention of complete prostheses (CPs) on four implants followed for 2 years. MATERIAL AND METHODS: Twenty-five patients received four implants and only one CPs for a total of 100 implants followed. Each prosthesis was supported by four implants. An immediate loading surgical protocol was used. The CPs were provided to be fixed to conometric abutments without prostheses removal by the patients, to test this retention for a fixed instead of a removable rehabilitation. Clinical and radiographical parameters were assessed at the yearly follow-up visit. A follow-up of 2 years was observed for each patient. Moreover, biological and technical complications were recorded. Changes overtime of clinical and radiographic parameters were analyzed as well as the satisfaction degree for each patient. RESULTS: No patient was classified as "dropout." The following results were observed after 2 years of follow-up: all the implants supporting the 25 CPs completed the follow-up examination. No implant, reconstruction, and abutment failure were recorded; therefore, the prosthetic survival was 100% for all the abutments and restorations. No significant differences in biological indexes were observed when compared with the baseline. No significant change of the mean marginal bone level (MBL) was found between the baseline and the last follow-up. No loss of retention was recorded for the CPs. No technical complications referred to abutments and frameworks were observed: a prosthetic survival rate of 100% can be recorded. Mucositis was recorded for two implants and successfully treated with interceptive supportive therapy. No significant differences (P < 0.05) were found between plaque index and MBi parameters at baseline and after 2 years of function. Similar results were recorded for the mean probing pocket depth Index at baseline (1.2 mm with SD of 0.3 mm) and after 2 years of function (1.2 mm with SD of 0.2 mm). CONCLUSIONS: The present implant-supported conometric retention system can be used to give a fixed retention to a CPs supported by four implants immediately loaded. Furthermore, costs reduction and simplified treatment procedures were provided by such a clinical approach.

Plasma rich in growth factors had limited effect on early bone formation in extraction sockets: Response to "Anitua, E., Alkhraisat, M.H. & Orive, G. (2013) Letter to the Editor: Rigorous methodology is the school of coherent conclusions in science. European Journal of Oral Implantology 6: 9-11.".

AIM: To address the criticisms raised by Anitua et al. (European Journal of Oral Implantology, 6, 2013, 9-11) to the article "Plasma Rich in Growth Factors (PRGF) in Human Post-Extraction Sockets: an Histological and Histomorphometric Study.", recently published by Farina and colleagues (Clinical Oral Implants Research 2012; doi: 10.1111/clr.12033). METHODS: All the methodological aspects criticized in the letter by Anitua et al. were thoroughly reconsidered and discussed in a structured short communication. When indicated, pertinent, additional material was included to reinforce our considerations. RESULTS: As most clinical studies in implant dentistry, including previous studies evaluating the efficacy/effectiveness of PRGF, the study by Farina et al. has some limitations. However, it is currently the only published controlled trial using quantitative parameters related to PRGF-induced early bone formation. CONCLUSIONS: Despite all limitations, the results of the study by Farina et al., which were based on different quantitative parameters (micro-CT scan, immunohistochemical markers of wound healing and bone deposition), indicated a limited effect of PRGF on early bone formation in extraction sockets.

Correlation between subjective and objective evaluation of peri-implant soft tissue color.

PURPOSE: While extensive references are present in the literature dealing with the correlation between subjective and objective evaluation of tooth shade, there is a lack of information on this correlation regarding the soft tissue color. The purpose of this experimental study was to verify whether a correlation between the objective and subjective evaluation exists in analyzing soft tissue color. MATERIAL AND METHODS: A total of 39 patients with at least one implant-supported restoration in the anterior maxilla were included in the study. The shade of the peri-implant mucosa was compared with the shade of the gingiva at the adjacent tooth in a subjective and in an objective manner. The subjective evaluation was performed by five dental professionals (prosthodontist, periodontist, general dentist, dental hygienist, and dental assistant) in a subjective scale (ranging from 1 to 4). The objective evaluation was obtained by means of a spectrophotometer in a CIELAB* Color Scale, and the differences were evaluated through formula ΔE=[(ΔL)²+(Δa)²+(Δb)²]¹/². To correlate the subjective and the objective evaluation, for each arithmetical median value of the subjective evaluation, a mean value of objective evaluation has been calculated, and the Spearman's rank correlation coefficient has been used. The differences have been also analyzed for thin and thick tissue biotypes. RESULTS: The mean ∆E value for the subjective evaluation between peri-implant soft tissue and adjacent tooth gingival tissue was ∆E = 9.74. Also, mean ∆E values of 10.35 and 7.54 have been reported for thin and thick biotypes, respectively. Mean values of ∆E = 6.63, 8.54, and 15.54 were presented by median values of 1 (perfect matching), 2 (good matching), and 3 (clinically distinguishable), respectively. The threshold for the distinction of differences of mucosal color by the human eyes between perfect or good matching and distinguishable values has been calculated in ∆E = 8.74. CONCLUSIONS: Within the limitation of this study, a correlation between the subjective and the objective evaluation of the peri-implant soft tissue exists and the threshold for the distinction of mucosal color differences between perfect or good matching and distinguishable subjective values has been calculated in ∆E = 8.74 in the objective evaluation.

Deproteinized bovine bone mineral particles and osseointegration of implants without primary bone contact: an experimental study in dogs.

OBJECTIVES: To evaluate the influence on osseointegration of Deproteinized bovine bone mineral (DBBM) particles used to fill defects of at least 1 mm around implants having no primary contact with bone. MATERIAL AND METHODS: Premolars and first molars were extracted bilaterally from the mandible of six Labrador dogs. After 3 months of healing, mucoperiosteal full-thickness flaps were elevated, and one recipient site was prepared in the molar region of each hemi-mandible to place implants. These were installed with a deliberate circumferential and periapical space to the bone walls of 1.2 mm. All implants were stabilized with passive fixation plates to maintain the implants in situ and without any contact with the implant bed. The control sites were left to be filled with coagulum, while at the test sites, the residual gap was filled with DBBM. After 3 months of submerged healing, the animals were sacrificed. Ground sections were prepared and analyzed histomorphometrically. RESULTS: Mineralized bone-to-implant contact was 4.0% and 3.9% for control and test sites, respectively. The width of the residual defects was 0.48 mm and 0.88 mm at the control and test sites, respectively. The percentage of implant surface covered by a layer of dense connective tissue of 0.12 mm of width on average was 84.9% and 88.5% at the control and test sites, respectively. CONCLUSION: A minor and not predictable degree of contact or distance osteogenesis was obtained on the implant surface when primary contact of the implant surface with the implant bed had deliberately been avoided. DBBM grafting of the artificial gap did not favor osseointegration. Neither did it enhance the ability to bridge the gap with newly formed bone in an artificial defect wider than 1 mm.

The platform switching concept revisited. An experimental study in dogs.

OBJECTIVE: To evaluate the influence of the configuration of the marginal aspect of implants placed immediately into extraction sockets on peri-implant hard tissue adaptation. MATERIAL AND METHODS: In 6 Labrador dogs, endodontic treatments of the mesial roots of 1 M1 were performed and the distal roots were removed. 2 P2 was extracted as well. Implants were immediately placed in the center of the distal alveoli. Cylindrical straight implants were installed in the right side of the mandible (Control), while, in the left side, implants with a reduced diameter in the coronal portion, yielding an indentation in the surface continuity (Test), were installed. Cover screws were affixed, and the flaps were sutured to allow non-submerged healing. After 4 months of healing, histological slides were obtained for assessments. RESULTS: A buccal resorption of 1.58 ± 1.28 and 1.90 ± 1.93 mm at the control and of 0.26 ± 0.90 and 0.14 ± 0.66 mm at the test sites was observed at the premolar and molar regions, respectively. The buccal coronal level of osseointegration was located apically to the margin of the smooth/rough surface border by 2.40 ± 0.90 and 3.70 ± 0.87 mm at the control sites and 1.19 ± 0.45 and 2.16 ± 0.96 mm at the test sites at the premolar and molar sites, respectively. All differences yielded statistical significance. CONCLUSIONS: The use of implants with a reduced diameter in their coronal aspect may contribute to preservation of the buccal bony crest in a more coronal level compared with conventional implants. Thus, the study confirmed the efficacy of the "platform switching" concept.

Effect of chlorhexidine in preventing plaque biofilm on healing abutment: a crossover controlled study.

INTRODUCTION: The study aimed at evaluating the effect of chlorhexidine (CHX) in preventing plaque biofilm (PB) formation on healing abutments (HAs) in patients rehabilitated with osseointegrated implants. MATERIALS AND METHODS: Fifty HAs were placed in 34 voluntary patients 1 week after implant surgery (test group). After 7 days, a new set of 50 HAs was placed in the same implant sites and removed 1 week after (control group). During the 2 testing periods, patients were instructed to apply: CHX mouth rinsing twice daily and no brushing (test); no CHX mouth rinsing and no brushing (control). Scanning electron microscopy and image analysis were blindly used to objectively quantify PB amount on removed HAs. RESULTS: Median values and interquartile ranges of the percent ratio of titanium surface covered from PB were 0.9 (0.1-4.1) and 1.2 (0.1-11.6) for test and control groups, respectively (P = 0.0275). CONCLUSIONS: CHX mouth rinsing significantly limited plaque formation on HAs, being a valid contribution to mechanical brushing in early phases of plaque control on dental implants.

Nanostructured guidance for peripheral nerve injuries: a review with a perspective in the oral and maxillofacial area.

Injury to peripheral nerves can occur as a result of various surgical procedures, including oral and maxillofacial surgery. In the case of nerve transaction, the gold standard treatment is the end-to-end reconnection of the two nerve stumps. When it cannot be performed, the actual strategies consist of the positioning of a nerve graft between the two stumps. Guided nerve regeneration using nano-structured scaffolds is a promising strategy to promote axon regeneration. Biodegradable electrospun conduits composed of aligned nanofibers is a new class of devices used to improve neurite extension and axon outgrowth. Self assembled peptide nanofibrous scaffolds (SAPNSs) demonstrated promising results in animal models for central nervous system injuries, and, more recently, for peripheral nerve injury. Aims of this work are (1) to review electrospun and self-assembled nanofibrous scaffolds use in vitro and in vivo for peripheral nerve regeneration; and (2) its application in peripheral nerve injuries treatment. The review focused on nanofibrous scaffolds with a diameter of less than approximately 250 nm. The conjugation in a nano scale of a natural bioactive factor with a resorbable synthetic or natural material may represent the best compromise providing both biological and mechanical cues for guided nerve regeneration. Injured peripheral nerves, such as trigeminal and facial, may benefit from these treatments.