The Root Membrane Technique: A Retrospective Clinical Study With Up to 10 Years of Follow-Up.

PURPOSE: Immediate implant placement in conjunction with intentional root retention is a recently introduced technique, but the majority of existing documentation is limited to short-term reports with low level of evidence. Hence, the aim of this study was to document the long-term clinical and radiographic results of the root membrane technique. METHODS: This retrospective study reports on clinical results of the root membrane technique for periodontal ligament-mediated immediate implant placement with up to 10 years of follow-up from 3 private dental practices. Anterior implants placed with immediate loading from January 2006 to December 2016 were assessed. Kaplan-Meier estimators were computed for reporting of implant success and survival. RESULTS: A sample of 182 patients (82 men and 100 women, age range: 18-83 years) received 250 immediate implants (230 maxilla, 20 mandible) after the root membrane concept and followed-up for a mean of 49.94 months (±32.5). Overall, 5 implant failures were recorded for a 10-year cumulative patient-level implant survival rate of 96.5%. Considering mechanical and biological complications, the 10-year cumulative implant success rate was 87.9%. CONCLUSIONS: Within the limits of the retrospective design, the root membrane technique showed long-term success rates comparable to those of conventional immediate implants.

Short (6-mm) dental implants versus sinus floor elevation and placement of longer (≥10-mm) dental implants: a randomized controlled trial with a 3-year follow-up.

OBJECTIVES: To investigate whether short (6-mm) dental implants could be an alternative to sinus floor elevation (SFE) and placement of longer (≥10-mm) implants in the posterior maxilla. MATERIALS AND METHODS: Over a 3-year period, all patients presenting with partial edentulism in the posterior maxilla were considered for inclusion in this randomized controlled trial. Patients were randomly chosen either to receive short (6-mm) implants (test group [TG]) or to undergo SFE with simultaneous placement of standard-length (≥10-mm) implants (control group [CG]). SFE was performed using the lateral technique. In both groups, tapered implants (AnyRidge, MegaGen, Gyeongbuk, South Korea) were placed. All implants were loaded after 4 months of healing. At each annual follow-up session, clinical and radiographic parameters were assessed. Primary outcomes were implant survival, stability (measured with the implant stability quotient [ISQ]), marginal bone loss (MBL), and complications; secondary outcomes were patient satisfaction and treatment time and cost. RESULTS: Thirty-three patients were assigned to the TG and 20 to the CG. Forty-five implants were inserted in each group. At 3 years, implant survival rates were 100% and 95.0% for the TG and CG, respectively; this difference was not statistically significant (P = 0.38). The mean ISQ values of the TG and CG did not differ at placement (68.2 vs. 67.8, P = 0.1), at delivery of the final restoration (69.5 vs. 69.4, P = 0.9), and after 1 year (71.0 vs. 71.5, P = 0.1); at 3 years, the CG had a significantly higher mean ISQ than the TG (72.4 vs. 71.6, P = 0.004). Mean MBL was significantly higher in the CG than in the TG, both at 1 year (0.14 mm vs. 0.21 mm, P = 0.006) and at 3 years (0.20 mm vs. 0.27 mm, P = 0.01). A few complications were reported. Surgical time and cost were significantly higher in the CG than in the TG (P < 0.0001). Patient satisfaction was high in both groups. CONCLUSIONS: In this randomized controlled trial, results for short (6-mm) implants were similar to those for longer (≥10-mm) implants in augmented bone. Short implants might be preferable to SFE, because the treatment is faster and less expensive. Long-term randomized controlled trials are required to confirm these results.

Trueness and Precision of Four Intraoral Scanners in Oral Implantology: A Comparative in Vitro Study.

PURPOSE: The aim of this study was to compare the trueness and precision of four intraoral scanners used in oral implantology. METHODS: Two stone models were prepared, representing a partially and a totally edentulous maxilla, with three and six implant analogues, respectively, and polyether-ether-ketone (PEEK) cylinders screwed on. The models were digitized with an industrial scanner (IScan D104I®) used as a reference, and with four intraoral scanners (Trios®; CS 3500®; Zfx Intrascan®; Planscan®). Five scans were taken for each model, using each different intraoral scanner. All datasets were loaded into reverse-engineering software (Geomagics 2012®), where intraoral scans were superimposed on the reference model, to evaluate general trueness, and superimposed on each other within groups, to evaluate general precision. General trueness and precision of any scanner were compared by model type, through an ANOVA model including scanner, model and their interaction. Finally, the distance and angles between simulated implants were measured in each group, and compared to those of the reference model, to evaluate local trueness. RESULTS: In the partially edentulous maxilla, CS 3500® had the best general trueness (47.8 µm) and precision (40.8 µm), followed by Trios® (trueness 71.2 µm, precision 51.0 µm), Zfx Intrascan® (trueness 117.0 µm, precision 126.2 µm), and Planscan® (trueness 233.4 µm, precision 219.8 µm). With regard to general trueness, Trios® was significantly better than Planscan®, CS 3500® was significantly better than Zfx Intrascan® and Planscan®, and Zfx Intrascan® was significantly better than Planscan®; with regard to general precision, Trios® was significantly better than Zfx Intrascan® and Planscan®, CS 3500® was significantly better than Zfx Intrascan® and Planscan®, and Zfx Intrascan® was significantly better than Planscan®. In the totally edentulous maxilla, CS 3500® had the best performance in terms of general trueness (63.2 µm) and precision (55.2 µm), followed by Trios® (trueness 71.6 µm, precision 67.0 µm), Zfx Intrascan® (trueness 103.0 µm, precision 112.4 µm), and Planscan® (trueness 253.4 µm, precision 204.2 µm). With regard to general trueness, Trios® was significantly better than Planscan®, CS 3500® was significantly better than Zfx Intrascan® and Planscan®, and Zfx Intrascan® was significantly better than Planscan®; with regard to general precision, Trios® was significantly better than Zfx Intrascan® and Planscan®, CS 3500® was significantly better than Zfx Intrascan® and Planscan®, and Zfx Intrascan® was significantly better than Planscan®. Local trueness values confirmed these results. CONCLUSIONS: Although no differences in trueness and precision were found between partially and totally edentulous models, statistically significant differences were found between the different scanners. Further studies are required to confirm these results.

Mesenchymal stem cells in maxillary sinus augmentation: A systematic review with meta-analysis.

AIM: To investigate the effectiveness of mesenchymal stem cells (MSCs) in maxillary sinus augmentation (MSA), with various scaffold materials. METHODS: MEDLINE, EMBASE and SCOPUS were searched using keywords such as sinus graft, MSA, maxillary sinus lift, sinus floor elevation, MSC and cell-based, in different combinations. The searches included full text articles written in English, published over a 10-year period (2004-2014). Inclusion criteria were clinical/radiographic and histologic/ histomorphometric studies in humans and animals, on the use of MSCs in MSA. Meta-analysis was performed only for experimental studies (randomized controlled trials and controlled trials) involving MSA, with an outcome measurement of histologic evaluation with histomorphometric analysis reported. Mean and standard deviation values of newly formed bone from each study were used, and weighted mean values were assessed to account for the difference in the number of subjects among the different studies. To compare the results between the test and the control groups, the differences of regenerated bone in mean and 95% confidence intervals were calculated. RESULTS: Thirty-nine studies (18 animal studies and 21 human studies) published over a 10-year period (between 2004 and 2014) were considered to be eligible for inclusion in the present literature review. These studies demonstrated considerable variation with respect to study type, study design, follow-up, and results. Meta-analysis was performed on 9 studies (7 animal studies and 2 human studies). The weighted mean difference estimate from a random-effect model was 9.5% (95%CI: 3.6%-15.4%), suggesting a positive effect of stem cells on bone regeneration. Heterogeneity was measured by the I (2) index. The formal test confirmed the presence of substantial heterogeneity (I (2) = 83%, P < 0.0001). In attempt to explain the substantial heterogeneity observed, we considered a meta-regression model with publication year, support type (animal vs humans) and follow-up length (8 or 12 wk) as covariates. After adding publication year, support type and follow-up length to the meta-regression model, heterogeneity was no longer significant (I (2) = 33%, P = 0.25). CONCLUSION: Several studies have demonstrated the potential for cell-based approaches in MSA; further clinical trials are needed to confirm these results.

Immediate loading of mandibular overdentures supported by one-piece, direct metal laser sintering mini-implants: a short-term prospective clinical study.

BACKGROUND: Only a few studies have dealt with immediately loaded, unsplinted mini-implants supporting ball attachment-retained mandibular overdentures (ODs). The aim of this study is to evaluate treatment outcomes of ball attachment-retained mandibular ODs supported by one-piece, unsplinted, immediately loaded, direct metal laser sintering (DMLS) mini-implants. METHODS: Over a 4-year period (2009 to 2012), all patients referred to the Dental Clinic, University of Varese, and to a private practice for treatment with mandibular ODs were considered for inclusion in this study. Each patient received three or four DMLS mini-implants. Immediately after implant placement, a mandibular OD was connected to the implants. At each annual follow-up session, clinical and radiographic parameters were assessed, including the following outcome measures: 1) implant failures; 2) peri-implant marginal bone loss; and 3) complications. Statistical analysis was conducted using a life-table analysis. RESULTS: A total of 231 one-piece DMLS mini-implants were inserted in 62 patients. After 4 years of loading, six implants failed, giving an overall cumulative survival rate of 96.9%. The mean distance between the implant shoulder and the first visible bone-to-implant contact was 0.38 ± 0.25 and 0.62 ± 0.20 mm at the 1- and 4-year follow-up examinations, respectively. An incidence of 6.0% of biologic complications was reported; prosthetic complications were more frequent (12.9%). CONCLUSIONS: Within the limits of this study, it can be concluded that the immediate loading of one-piece, unsplinted, DMLS titanium mini-implants by means of ball attachment-supported mandibular ODs is a successful treatment procedure. Long-term follow-up studies are needed to confirm these results.

A light and scanning electron microscopy study of human direct laser metal forming dental implants.

Direct laser metal forming (DLMF) is a procedure in which a high-power laser beam is directed on a metal powder bed and programmed to fuse particles according to a computer-aided design file, thus generating a thin metal layer. With DLMF, it is now possible to fabricate dental implants with a superficial porous surface. The aim of the present study was to evaluate the peri-implant soft tissues around human-retrieved DLMF dental implants. Collagen fibers, in the form of bundles, were oriented perpendicularly to a distance of 100 µm from the surface, where they became parallel, running in several directions. In some portions, only a few collagen fiber bundles appeared to be oriented perpendicularly or obliquely to the plane of the section. Collagen fibers appeared to form a dense chaotic three-dimensional network running in different, more or less parallel directions to the surface. Under scanning electron microscopy, an intimate contact of the fibrous matrix with the implant surface was evident, and some collagen bundles could be seen to bind directly to the metal surface. By changing the surface microtexture, it was possible to change the response of the peri-implant soft tissues.

Maxillary sinus augmentation with adult mesenchymal stem cells: a review of the current literature.

PURPOSE: Mesenchymal stem cells (MSCs) have been applied in maxillary sinus augmentation (MSA) with clinically successful results. The purpose of this article was to evaluate the systematically acquired evidence for the effectiveness of cell-based approaches in MSA with various scaffolds, and to narratively assess evidence from additional articles that report effectiveness of cell-based approaches in MSA. MATERIALS AND METHODS: Electronic database searches were performed. Inclusion criteria were studies of cell-based approaches in MSA with various scaffolds, in humans, with at least 3 to 4 months of follow-up. Meta-analysis was performed for randomized controlled trials (RCTs) with histologic/histomorphometric evaluation. RESULTS: Fifteen studies (4 RCTs) were considered to be eligible for inclusion in the review. The meta-analysis suggested a marginal, nonstatistically significant positive effect of MSCs on the bone regrowth. CONCLUSIONS: A number of studies have demonstrated the potential for cell-based approaches in MSA; further RCTs that clearly demonstrate benefits of cell-based approach are needed.

Esthetic evaluation of single-tooth Morse taper connection implants placed in fresh extraction sockets or healed sites.

The aim of this study was to compare the esthetic outcome of single implants placed in fresh extraction sockets with those placed in fully healed sites of the anterior maxilla. This retrospective study was based on data from patients treated with single-tooth Morse taper connection implants placed in fresh extraction sockets and in fully healed sites of the anterior maxilla. Only single implant treatments were considered with both neighboring teeth present. Additional prerequisites for immediate implant treatment were intact socket walls and a thick gingival biotype. The esthetic outcome was objectively rated using the pink esthetic/white esthetic score (PES/WES). The Mann-Whitney U test was used to compare the PES and the WES between the 2 groups. Twenty-two patients received an immediate implant, and 18 patients had conventional implant surgery. The mean follow-up was 31.09 months (SD 5.57; range 24-46) and 34.44 months (SD 7.10; range 24-48) for immediately and conventionally inserted implants, respectively. No implants were lost. All implants fulfilled the success criteria. The mean PES/WES was 14.50 (SD 2.52; range 9-19) and 15.61 (SD 3.20; range 8-20) for immediately and conventionally placed implants, respectively. Immediate implants had a mean PES of 7.45 (SD 1.62; range 4-10) and a mean WES of 7.04 (SD 1.29; range 5-10). Conventional implants had a mean PES of 7.83 (SD 1.58; range 4-10) and a mean WES of 7.77 (SD 1.66; range 4-10). The difference between the 2 groups was not significant. Immediate and conventional single implant treatment yielded comparable esthetic outcomes.

Immediate loading of mandibular overdentures supported by unsplinted direct laser metal-forming implants: results from a 1-year prospective study.

BACKGROUND: At present, only some studies have dealt with immediate loading of unsplinted implants supporting mandibular overdentures. The aim of this prospective study is to evaluate treatment outcomes of mandibular overdentures supported by four one-piece, unsplinted, immediately loaded, direct laser metal-forming (DLMF) implants by assessing implant survival rate, implant success, marginal bone loss, and prosthetic complications. METHODS: A total of 96 one-piece DLMF implants were inserted in the edentulous mandible of 24 patients. Four implants were placed in each edentulous mandible. Immediately after implant placement, a mandibular overdenture was connected to the implants. At 1-year follow-up, clinical, radiographic, and prosthetic parameters were assessed. Success criteria included absence of pain, suppuration, and implant mobility; absence of continuous peri-implant radiolucency; and distance between the implant shoulder and the first visible bone contact <1.5 mm. RESULTS: After a 1-year loading time, the overall implant survival rate was 98.9%, with only one implant lost. Among the surviving 95 implants, two did not fulfill the success criteria; therefore, the implant success rate was 97.8%. The mean distance between the implant shoulder and the first visible bone contact was 0.28 ± 0.30 mm (95% confidence interval, 0.24 to 0.32). Some prosthetic complications were reported. CONCLUSION: Based on the present results and within the limits of this study, the immediate loading of four unsplinted DLMF implants by means of ball attachment-supported mandibular overdentures seems to represent a safe and successful procedure.