SMOKING MIGHT INCREASE THE FAILURE RATE AND MARGINAL BONE LOSS AROUND DENTAL IMPLANTS.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Mustapha AD, Salame Z, Chrcanovic BR. Smoking and Dental Implants: A Systematic Review and Meta-Analysis. Medicina. 2021 Dec 27;58(1):39. SOURCE OF FUNDING: No external sources of funding were available for conducting this study. TYPE OF STUDY/DESIGN: Systematic review (SR) with meta-analysis (MA) of data.

Biomechanics of 3-implant-supported and 4-implant-supported mandibular screw-retained prostheses: A 3D finite element analysis study.

STATEMENT OF PROBLEM: The number of implants required for the rehabilitation of completely edentulous mandibles has been controversial. The use of a greater number of implants can produce favorable biomechanical outcomes. However, this will lead to high costs and may require complex surgical procedures. Therefore, the minimum number of implants that can produce desirable outcomes should be used. PURPOSE: The purpose of this 3D finite element study was to compare the biomechanics of mandibular 3-implant-supported to 4-implant-supported prostheses. The opposing occlusion was a maxillary complete denture or natural dentition. MATERIAL AND METHODS: Two finite element analysis mandibular anatomic models were created. Implants were virtually placed in the mandibular lateral incisor and second premolar region bilaterally in the 4-implant-supported prosthesis model. For the 3-implant-supported model, they were placed in the midline and bilaterally in the second premolar region. Screw-retained polymethyl methacrylate prostheses were designed. Reverse engineering was used to convert standard tessellation language files into computer-aided design solid models. Vertical and oblique loading was applied twice: simulating an opposing maxillary complete denture and a natural dentition. Von Mises stresses and equivalent strains generated in the peri-implant bone, implants' von Mises stresses and the maximum vertical displacement of the prosthesis were recorded. RESULTS: All recorded outcomes reported higher values for the 3-implant-supported prosthesis compared with the 4-implant-supported models for both applied loads. When opposed by a maxillary complete denture, maximum strain values for the 3-implant-supported (2.3×103 µÎµ) and 4-implant-supported (1.6×103 µÎµ) models were less than the different threshold limits for the bone resorption reported (3×103, 3.6×103, 6.6×103 µÎµ). When opposed by a maxillary natural dentition, maximum strain values for the 3-implant-supported (4.10×103 µÎµ) and 4-implant-supported (3.88×103 µÎµ) models were less than the highest reported threshold limit for bone resorption (6.6×103 µÎµ) in contrast with other reported threshold limits (3×103, 3.6×103 µÎµ). In both designs irrespective of the magnitude and direction of loading, the maximum recorded von Mises stresses of the implants (126 MPa) and denture displacement (3.24×102 µm) were less than titanium's yield strength of (960 to 1180 MPa) and the displacement values (5.2×103 to 8.8×103 µm) reported in the literature. CONCLUSIONS: When opposed by a complete denture, recorded biomechanical outcomes for the 3- and 4-implant-supported designs were within physiologic limits. When opposed by a natural dentition, the von Mises stresses of the implants and denture displacement values for both designs were within a favorable mechanical range, whereas peri-implant stresses and strain exceeded most reported physiologic tolerance levels of bone except for the 6.6×103 µÎµ threshold limit for the bone resorption reported.

Osseodensification in Implant Dentistry: A Critical Review of the Literature.

INTRODUCTION: Osseodensification is a technique that aims at bone preservation and compaction either through nonsubtractive drilling or implants with a special thread design. This can increase quantity and density of periimplant bone. This review represents a summary and a critical appraisal of the studies regarding osseodensification in the literature. MATERIALS AND METHODS: Three databases were searched: PubMed (MEDLINE), Cochrane Library, and Latin American and Caribbean center on health sciences information (LILACS). Studies were screened by title/abstract according to predetermined eligibility criteria. Full texts of 7 eligible articles were read among which 2 were excluded and 5 articles were included and underwent qualitative synthesis. DISCUSSION: Studies advocating osseodensification are sparse and mainly animal studies of low evidence level. High risk of bias and low correlation between used animal models and human bone were detected in most of the studies. CONCLUSION: Although osseodensification seems to be a very promising technique, the findings are inconclusive and should be cautiously interpreted. Well-designed animal and human studies of longer follow-up periods are required before implementing such technique in regular daily practice.