Evaluation of internal and external hexagon connections in immediately loaded full-arch rehabilitations: A within-person randomized split-mouth controlled trial with a 3-year follow-up

Clinical study with sandblasted dental implants: a 17-year retrospective follow up

Sandblasting is a standard procedure used for treating dental implant (DI) surfaces to enhance the osseointegration with known clinical success. This clinical study aimed to evaluate the long-term clinical outcomes of DIs with external hexagon connections and a surface sandblasted with calcium phosphate. Two hundred and seventy-five Mg-osseous™ (Mozo-Grau™) screw DIs were placed in 86 patients using a two-stage surgical technique and conventional loading protocol (at three months). Dental implants and prosthetic clinical findings were evaluated during a 17-year follow up. Four DIs were lost during the healing period, and 108 prostheses were placed over the 271 DIs left: 58 unitary implant-supported prosthesis (ISP), 31 partially ISP, 14 full-arch ISP, and five overdentures. Fourteen DIs were lost during the follow-up period. Clinical results indicated a DI survival rate of 93.50%. A total of 11.80% of DIs showed peri-implantitis as the primary biological complication. The mean (SD) marginal bone loss was 1.78 (0.40) mm, ranging from 0.90 to 2.80 mm. The most frequent complication was mechanical prosthodontic complications (24.40%). Sandblasted surface DIs inserted in both maxillary and mandibular areas produce favourable long-term (17-year follow up) outcomes and stable tissue conditions when a delayed loading protocol is followed.

Bruxism and dental implants: A systematic review and meta-analysis

BACKGROUND

Overload from bruxism may affect survival of dental implants.

OBJECTIVES

To evaluate implant failure and marginal bone loss (MBL) in patients presenting with probable bruxism compared to non-bruxers. The study was registered in PROSPERO (CRD42021238397).

METHODS

An electronic search September 2022 in PubMed/Medline, Web of Science and Science Direct was combined with a hand search. Two independent reviewers carried out abstract screening, full-text assessment, quality assessment (National Institutes of Health tool) and data extraction. Only studies that provided information on self-report and clinical examination needed for the diagnosis of at least 'probable' bruxism were included. A pairwise random-effect meta-analysis was carried out.

RESULTS

In total 1338 studies were identified, and after screening and full-text assessment 27 studies that presented data on 2105 implants in probable bruxers and 10 264 implants in non-bruxers were included, with 138 and 352 implant failures in respective groups. the meta-analysis showed that implants placed in probable bruxers had a higher risk of failure than in non-bruxers (OR 2.189; 95% CI 1.337, 3.583, p = .002). A meta-regression showed that follow-up time did not affect this OR. Eighteen studies provided general data on MBL but did not report results separated between bruxers and non-bruxers. Therefore, an analysis of MBL was not possible.

CONCLUSION

The results of the present systematic review show that implants placed in probable bruxers present a significantly higher risk of failure than implants placed in non-bruxers. This should be considered in treatment planning and management of implant patients.

Biomechanical Analysis of Titanium Dental Implants in the All-on-4 Treatment with Different Implant-Abutment Connections: A Three-Dimensional Finite Element Study

The type of implant-abutment connection is one of the factors influencing the distribution of occlusal forces. This study aims to investigate the biomechanical performance of the mandibular all-on-4 treatment with different implant-abutment connections. Two connection types with 30° abutments and 18-mm implant fixtures were chosen for the posterior implants of the all-on-4 assembly. For the external hexagon connection (EHC) group, the implants with 4 mm in diameter were used. For the internal hexagon connection (IHC) group, we selected implants with 4.3 mm in diameter. A vertical force of 190 N was applied to the cantilever region. The FEA results indicated that the most stressed region in the two groups was prosthetic screws, followed by multi-unit abutments (MUAs). The lowest values of von Mises stress were both observed on the bone. The peak stress value of the implant screw and implant fixture in the EHC group were 37.75% and 33.03% lower than the IHC group, respectively. For stress distribution patterns, the load force tended to be concentrated at locations where components were interconnected. The EHC and IHC are clinically durable under the tested loading conditions, but the prosthetic screws and MUAs can be the weak point on the posterior implant within the mandibular all-on-four assembly. The peak stress values of implant screw and implant fixture in the EHC groups were lower than the IHC group.

A temporospatial histomorphometric analysis of bone density adjacent to acid-etched self-tapping dental implants with an external hexagon connection in the female baboon

OBJECTIVE

To characterize osseointegration as the percent of bone-implant contact (%BIC) along the surface (0.0 mm) as well as at surface profiles 0.5 mm and 1.0 mm lateral to the implant, determining any differences between early occlusally loaded and non-loaded implants.

MATERIAL AND METHODS

In ten adult female baboons, 120 dental implants were randomly placed in opposing mandibular and maxillary locations. Eighty sites had two groups of healing (no load) of either 1 (n = 40) or 2 (n = 40) months leading to 3 months of functional loading. These sites received full acid-etched surface implants. The 40 control implants represented healing only periods (no load) for 1 (n = 10), 2 (n = 10), 4 (n = 10), and 5 (n = 10) months. These implants were of a vertically split surface texture design (acid-etched and machined). Block sections and photomicrographs were obtained. Blinded histometric analyses determined the %BIC via a superimposed template.

RESULTS

The unloaded groups (1, 2, and 4 months) had higher %BIC compared to the 5-month group (p < 0.0001). The loaded groups exhibited mean bone densities of 59.2% and 55.5% (1-month healing at 0.5 mm and 1.0 mm, respectively) and 61.0% and 57.1% (2-month healing at 0.5 mm and 1.0 mm, respectively) with no significant difference between healing time (p = 0.4118).

CONCLUSION

There was a lateral increase in %BIC in the loaded compared to unloaded groups.

CLINICAL RELEVANCE

The decrease in bone densities at the 5-month unloaded group suggests that there is a critical earlier time period when dental implants should be placed into functional load.