Background: Alveolar ridge resorption (ARP) is a well-recognized consequence of tooth extraction, and multiple adjacent extractions may lead to greater ridge reduction than single-tooth extractions. This multicenter randomized controlled trial aimed to assess ridge remodeling after removing 2 adjacent teeth and whether socket grafting with deproteinized bovine bone mineral with collagen (DBBM-C) plus a collagen membrane could counteract the ridge reduction.

Methods: Forty-two patients requiring 2 adjacent tooth extractions were randomly assigned to either Test (DBBM-C graft + collagen membrane) or Control (natural healing). Impressions were taken immediately after extraction and at 6 months, and models were analyzed to measure changes in horizontal ridge width (bucco-lingual at 3 mm below the crest) and vertical ridge height (buccal and lingual).

Results: At 6 months, grafted sites had significantly less ridge reduction than controls. Horizontal ridge width reduction averaged 57.7% in Control versus 23.0% in Test (p < 0.001). Vertical height loss was also greater in controls (buccal 3.0 mm vs. 1.5 mm; lingual 2.2 mm vs. 1.3 mm; p < 0.001). Both mesial and distal sockets benefited similarly from grafting, with comparable preservation at each site.

Conclusion: Filling adjacent extraction sockets with DBBM-C and covering with a collagen membrane significantly reduced horizontal and vertical alveolar ridge resorption compared to unassisted healing. This approach effectively preserves bone volume after multiple tooth extractions, which may facilitate later implant placement.

Plain language summary: When 2 neighboring teeth are removed, the area tends to shrink in width and height as it heals. This bone loss can make it more difficult to place dental implants later. In this study, we tested a method to help maintain the bone after removing 2 adjacent teeth. In the Test group, the empty tooth sockets were filled with a bone graft material (deproteinized bovine bone mineral and collagen) and covered with a collagen membrane. In the Control group, the sites were left to heal physiologically. A total of 42 patients participated, each needing 2 side-by-side teeth removed. After 6 months of healing, we compared models of the patients from right after the extractions to those taken 6 months later. The results showed that the group with the bone graft and membrane had much less bone shrinkage than the group without them. The 2 extraction sites in the graft group maintained their bone height and width similarly. In summary, using a bone substitute material and membrane immediately after multiple tooth extractions helped preserve the jawbone, which could make future treatments like dental implants more successful.

PURPOSE: Conventional screw- and cement-retained single implant restorations are associated with biological and technical complications. Friction-retained conometric concepts have been proposed as an alternative; however, clinical evidence for single crowns, particularly from prospective multicenter studies, remains limited. This study evaluated the 1-year clinical performance of a conometric retention system for implant-supported single crowns.

METHODS: This prospective multicenter study was conducted at nine clinical centers in Europe and North America. Subjects requiring single-tooth replacement in the maxilla or mandible received one implant restored with a prefabricated 5.9° conometric abutment and a titanium nitride-coated coping. All-ceramic crowns were extraorally bonded and seated without cement or screws. Radiographs were obtained at implant placement, delivery of the permanent restoration, and after 1 year. Primary outcomes were implant and prosthetic survival. Secondary outcomes included marginal bone level (MBL) changes, bleeding on probing, plaque, probing pocket depth, and complication rates. Descriptive statistics and confidence intervals were calculated.

RESULTS: A total of 144 implants were included in the per-protocol analysis. Three implants failed after delivery of the permanent restoration, resulting in a 1-year implant survival rate of 96.7%. Of 131 restorations evaluated at 1 year, 4 showed irreversible loss of conometric retention and were classified as prosthetic failures. In total, 22 prosthetic complication events were recorded, including 18 reversible technical complications (12.5%) and 4 irreversible failures, corresponding to an overall complication rate of 15.3%. Mean MBL change was - 0.11 mm from implant placement to PR and - 0.02 mm from PR to 1 year.

CONCLUSIONS: Within the limitations of this 1-year analysis, the investigated conometric retention system demonstrated high implant and prosthetic survival rates and limited marginal bone changes. However, a clinically relevant incidence of technical complications, including irreversible loss of conometric retention, was observed during the first year of function. These findings suggest that the conometric concept may require careful case selection and clinical monitoring. Long-term follow-up is required to further evaluate the clinical stability and prosthetic reliability of this retention concept over time.

TRIAL REGISTRATION: ClinicalTrials.gov, ID, NCT04063878, August 20, 2019.

Background/Objectives: Limited residual bone height in the atrophic posterior maxilla complicates implant placement. Transcrestal sinus elevation can be used to correct bone shrinkage after sinus pneumatization or crestal bone loss. This study evaluated a minimally invasive, one-stage transcrestal sinus lift using a double-layer crosslinked collagen scaffold (MCCS) with autogenous bone from the implant osteotomy site in patients with RBH ≤ 6 mm. Methods: In this prospective series, 11 patients (48–64 years, mean RBH 4.75 mm, SD 0.95 mm) underwent one-stage transcrestal sinus floor elevation with simultaneous implants. After osteotomy, autogenous bone chips collected during drilling were compacted into the site, and two layers of MCCS were placed under the elevated Schneiderian membrane. Buccal and palatal bone heights were measured on CBCT before and after surgery to assess vertical bone gain (ΔRBH). Results: All implants achieved stable osseointegration. Mean ΔRBH was approximately 3.1 ± 0.9 mm (combined buccal–palatal). No postoperative complications occurred. Two small Schneiderian membrane perforations were sealed intraoperatively by MCCS placement, with uneventful healing. Follow-up imaging showed maintenance of the augmented bone around the implants. Conclusions: This double-layer MCCS plus autogenous bone approach is a safe, effective, and minimally invasive transcrestal sinus lift for atrophic maxillae. It yielded crestal bone gains even with minimal initial RBH, leveraging the palatal sinus wall’s osteogenic potential and the implant’s tent-pole effect. The MCCS scaffold maintained space for bone formation and enabled immediate sealing of any membrane perforations. This one-stage protocol is viable for implant placement in low-RBH sites.

Background/Objectives: Immediate implant placement in the esthetic zone can shorten treatment time but maintaining peri-implant soft tissue stability is challenging. Conventional multi-stage workflows require multiple visits and may disturb peri-implant tissues. Placing a definitive one-time abutment at surgery can preserve soft tissue contours by avoiding multiple abutment changes. This case report introduces a digital one-stage approach delivering a definitive zirconia crown with delayed occlusal veneering at surgery to streamline treatment and preserve tissue stability. Methods: A 60-year-old male with a failing maxillary canine underwent immediate implant placement using guided surgery. A customized healing abutment preserved the emergence profile for the definitive restoration. A zirconia crown with an occlusal cut-back was fabricated and delivered at surgery on the one-time abutment without occlusal contact. After 12 weeks, a ceramic overlay was bonded extraorally to the crown to restore the occlusal surface. Results: At 2-year follow-up, the implant exhibited stable bone and healthy peri-implant soft tissues, with no complications. The one-time approach preserved tissue contours by eliminating provisional stages, and delayed occlusal veneering provided excellent esthetic integration. The patient was satisfied with the immediate result and fewer visits. This one-stage approach required fewer interventions than conventional provisional workflows. Conclusions: Immediate implant placement with a one-time abutment and delayed occlusal loading preserved peri-implant tissue architecture and achieved excellent functional and esthetic outcomes at 2 years. This one-stage workflow is a tissue-preserving alternative to multi-stage protocols; further studies are needed to confirm its long-term efficacy.

Purpose: To evaluate the effect of ceramic firing cycles on the interface of screw-retained implant-supported metal-ceramic fixed dental prostheses (FDPs). Materials and Methods: A total of 22 frameworks were produced in cobalt-chrome (CoCr) alloy using an integrated CAD/CAM system. The frameworks were manufactured with an additive process on the milled implant-framework interface (IFI). The total distortion of the interface was measured before (T1) and after (T2) the ceramic firing thermal cycles. The interface distortion was measured using a coordinate measuring machine (CMM) with an uncertainty of 2.5 nm, a resolution of 25 nm, and a universal software for dimensional metrology. To test whether there was a significant difference in total 3D distortion, Kruskal-Wallis test and Dunn test were employed; linear distortions between groups were compared using Kolmogorov-Smirnov test and Mann-Whitney test. A P value of <= .05 was considered statistically significant. Results: The total 3D distortion between the nominal value and T1 was 0.5 +/- 1.0 & micro;m, between the nominal value and T2 was 10.5 +/- 4.9 & micro;m, and between T1 and T2 was 10.6 +/- 4.9 & micro;m. The distortion between T1 and the nominal value was significantly smaller than that between the other two groups. The average deviations around the three axes and diameters were not significantly different among the three groups. Conclusions: CAD/CAM manufacturing of the IFI is an accurate process and does not present appreciable distortions. The ceramic firing cycles induce 3D-interface distortion. The observed distortion values were well below clinically relevant levels.

ObjectivesThis 5-year multicenter randomized clinical trial assessed the non-inferiority of maxillary implant-supported fixed complete dentures (FCDs) with four (4-I) compared to six implants (6-I) in terms of radiographic marginal bone level (MBL) changes after 5 years in function.Materials and MethodsIndividuals were randomly assigned to the 4-I or 6-I groups. Follow-ups occurred at 1, 3, and 5 years. At each visit, FCDs were unscrewed, clinical parameters (plaque index, bleeding on probing, pocket depth, and keratinized mucosa width) were recorded using a periodontal probe, periapical radiographs were obtained, and maintenance care was performed. MBL changes, incidence of techincal, prosthetic, and biological complications, treatments costs, and satisfaction were evaluated.ResultsOf 47 patients rehabiliated with 233 implants, survival rates were 99.3% for 6-I and 100% for 4-I (one early failure; 6-I group). No significant MBL differences were observed at 5 years between and within the groups. Both groups showed a decrease in keratinized mucosa width and experienced prosthetic and biological complications, but no peri-implantitis. The 4-I exhibited a significantly higher incidence of technical complications (16.6% vs. 0%) Cost analysis favored 4-I for initial and total costs. Clinician and patient satisfaction varied, with 4-I preferred aesthetically and 6-I functionally, particularly in speaking ability at earlier follow-ups.ConclusionThe use of FCDs supported by four implants is non-inferior to six implants in terms of radiographic MBL changes after 5 years in function. Both groups demonstrated comparable survival rates and incidence of biological and prosthetic complications. The 4-I was associated with higher technical complications and reduced overall treatment cost.Trial RegistrationClinicalTrials.gov identifier: NCT02405169

OBJECTIVES: Dental implant surgery relies extensively on bone drilling, a critical procedure with intrinsic challenges. Drill bits show significant wear and are frequently utilized beyond the manufacturer's recommended limits. Such practices can result in adverse effects, including friction and temperature rise in the surrounding bone area during interventions, with an increased risk of necrosis that can compromise the dental implant osseointegration. This study aimed to compare the quality of osteotomy obtained from two different protocols to determine a possible correlation between the drilling temperature and the tool wear and to evaluate their impact on potential health damage.

MATERIALS AND METHODS: Experimental evaluations were conducted using synthetic bone that reproduced human bone characteristics. The drilling phase involved real-time temperature acquisition and scanning electron microscopy analysis of tool wear evolution. After the operation, actual hole size and geometry were characterized using a coordinate measuring machine, and temperatures and torques were measured during the subsequent implantation phase.

RESULTS: The findings revealed a direct correlation between tool wear and the temperature rise during the drilling phase, while a lower correlation was found with the hole profile geometry variation. The implantation phase demonstrated temperature and torque values within acceptable ranges.

CONCLUSIONS: This study highlights the importance of adhering to proper tool maintenance and replacement protocols. By following recommended guidelines, practitioners can minimize adverse effects and enhance the success of dental implant procedures.

Background: Inter-implant distance (IID) plays a crucial role in maintaining peri-implant bone stability and osseointegration. Narrower IIDs (< 3 mm) have been associated with increased bone loss, but the threshold varies with implant connection type. The undersized preparation protocol, which induces static strain in the bone, enhances primary stability but may lead to microstructural damage, remodelling, or necrosis. The effect of this technique on osseointegration in adjacent implants with varying IIDs is not well documented. This study investigates the impact of undersized and non-undersized preparation protocols on osseointegration at different IIDs.

Methods: The study utilized eight sheep, with 64 implants placed in the mandibles following two surgical protocols: undersized preparation (UP) and non-undersized preparation (NUP). Implants were positioned at two IIDs (2 mm and 4 mm). Biomechanical, histomorphometric, and micromorphometric analyses were performed five weeks post-surgery. Bone-to-implant contact (BIC), bone volume fraction (BVTV), and bone mineral density (BMD) were measured in the regions of interest (inner and outer portions relative to the IID). A linear mixed model approach was applied to analyse the data with statistical significance set at p < 0.05.

Results: The analyses showed no statistically significant differences between the surgical protocols or IIDs for the evaluated parameters ( p >0.05). Nevertheless, trends were observed, with higher BIC and increased bone remodelling in the inner regions at 2 mm IID, particularly when using the undersized preparation protocol. Additionally, BVTV values were higher in the inner portions at 4 mm IID, suggesting reduced bone remodelling compared to 2 mm IID. These results indicate that while mechanical stress influenced trends in bone response, the overall resilience of peri-implant bone healing was evident.

Conclusions: No significant differences in osseointegration were observed between surgical protocols or IIDs. However, the trend of increased remodelling and higher BIC at 2 mm IID highlights the mechanical impact of undersized preparation in close implant spacing. These findings emphasize the complexity of peri-implant bone response to mechanical forces, necessitating further clinical studies to validate these results in human models.

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.

This investigation was designed to evaluate crestal bone stability and soft tissue maintenance to Laser-Lok tapered tissue-level implants. Twelve patients presenting with an edentulous site adequate for the placement of two implants were recruited from four dental offices (2 to 4 patients per office). Each patient received two Laser-Lok tissue-level implants placed with a 3-mm interimplant distance according to a surgical stent. The implants were placed so that the Laser-Lok zone sat at the junction between hard and soft tissues. A total of 24 implants were placed, and all achieved satisfactory crestal bone stability and soft tissue maintenance 1 year after receiving the final prosthetic restoration.