Sinus floor elevation and simultaneous implant placement in fresh extraction sockets: a systematic review of clinical data.

Combining different procedures to reduce the number of surgical sessions and patient discomfort in implant placement and sinus floor elevation has been recommended, and evidence supports good outcomes. The aim of this study was to review the results of clinical studies on sinus floor elevation through extraction sockets and simultaneous immediate posterior implant placement. An electronic search was carried out in PubMed, Scopus, and Web of Science to find English articles published in or before August 2020. A manual search was also performed. Titles, abstracts, and the full-text of the retrieved articles were studied. Thirteen studies met our eligibility criteria: 6 retrospective case series, 3 case reports, 2 prospective cohort caseseries, 1 prospective case series, and 1 randomized controlled trial. Overall, 306 implants were placed; 2 studies reported implant survival rates of 91.7% and 98.57%. The others either did not report the survival rate or reported 100% survival. Sinus floor elevation through a fresh extraction socket and simultaneous immediate implant placement appears to be a predictable modality with a high success rate. However, proper case selection and the expertise of the clinician play fundamental roles in the success of such complex procedures.

Evaluation of Stress and Strain Magnitude in Tapered and Cylindrical Implant Surrounding Bone, Used for Restoration of Mandibular Teeth: Finite Element Analysis in All-on-Four Concept.

The prevalence of the elderly population increased in the 20th century, as described in the World Health Organization 2004 Annual Report. The use of tilted implants parallel to the anterior wall of the maxillary sinus or the mental foramen/inferior alveolar nerve has been proposed for the treatment of the atrophic edentulous ridge. The aim of this study was to evaluate stress and strain magnitude in tapered and cylindrical surrounding bones. A 3D finite element model of an edentulous mandible was constructed. Two models of implants were used: cylindrical and tapered BEGO Semados RI Implants. Four implants were inserted between the bilateral mental foramen according to All-on-Four concept, and a mandibular bar was designed to use with the All-on-Four bar supported models. A vertical and 30 degree vertical load of 100 N was applied to both cylindrical and tapered implants models. Strain and stress were analyzed with ANSYS software (ANSYS R18.0). The maximum stress and strain were applied in all axes for the posterior man-dibular areas in the crestal region of the bone, and for the anterior areas at the intraosseous contact site. Also, the stress and strain of the bone under force in all axes in all areas for tapered implants is less compared to that for cylindrical implants. We found that the highest rate of bone resorption occurs in the posterior areas near the junction of the fixture with the abutment of implant, and in the anterior areas near the end of the fixture of implant. Still, more research on the subject is needed.

Stress and Strain Distribution Patterns in Bone around Tissue- and Bone-Level Implant-Supported Mandibular Overdentures Using Three-Dimensional Finite-Element Analysis.

Our aim is to investigate the effect of implant placement in two positions (bone level and tissue level) on stress and strain distribution around mandibular implant overdentures. We use two models of mandibular overdentures. Taper implants are inserted and collimated between the lateral and canine teeth. All structures are scanned, digitized, and three-dimensioned (3D) model designed. We apply a vertical load of 100 N simultaneously on the central fossa of the mandibular first molar of the two models (bone- and tissue-level implant). Stress and strain values are obtained using 3D finite-element analysis (FEA). In comparison to the tissue-level model, bone-level implants can reduce overdenture movement and tension by 0.8 µm. The results of this study show that using bone-level implants can reduce tension on the prosthesis part of the overdenture and the bone around the implants as well as on the movement of the distal end of the mandibular overdenture. We found that bone strain occurred around implants within physiological limits in model 1 (bone level) compared to model 2 (tissue level). This shows that the distribution of physical forces in bone-level implants generally produces better results than those of issue-level implants. However, more research on the subject is needed.

Effect of Topical Honey on Mandibular Bone Defect Healing in Rats.

AIM: In medicine, honey is known for its various biological or pharmacological effects, from wound dressing to anticancero-genic and from anti-inflammatory to antibacterial activities. The aim of the current study was to evaluate the effect of honey on healing of mandibular bone defects in a rat model. MATERIALS AND METHODS: This animal study was performed on 24 wild-type Wistar rats. Following shaving, disinfection, and extraoral incision, a 2 × 2 mm defect was created at mandibular angle. In the experimental group, the defect was filled with sterile honey, while it was left unfilled in the control group. The rats were sacrificed after 2 and 4 weeks and defects were assessed histologically. The results were compared using Mann-Whitney U-test (α = 0.05). RESULTS: After 2 weeks, five samples of the experimental group were in mineralization phase, while all samples of the control group were in the vascularization phase (p = 0.015). After 4 weeks, the defects were filled in four samples of the experimental group, while all samples of the control group were in the mineralization stage (p = 0.002). Histomorphometric assessment revealed that the mean new bone formation in the experimental group was significantly more than the control group, both after 2 and 4 weeks (p = 0.041). CONCLUSION: The results showed that honey could accentuate bone healing of mandibular small defects in rats. CLINICAL SIGNIFICANCE: Honey might have potential in repair of human alveolar bone defects.

Comparison of Attachment and Proliferation of Human Gingival Fibroblasts on Different Collagen Membranes.

BACKGROUND AND AIM: Human gingival fibroblasts cultured on collagen membrane as an alternative treatment method used in tissue regeneration can lead to improved results in root coverage. The aim of this study was to evaluate the human gingival fibroblast proliferation and adhesion cultured on three types of collagen membranes. MATERIALS AND METHODS: In this in vitro study, first-line human gingival fibroblast cells (HGF1-RT1) prepared and cultured on three membranes, including porcine pericardium (PP) (Jason, Botiss dental), human pericardium (HP) (Regen, Faravardeh Baft Iranian), and glutaraldehyde cross-linked (GC) (BioMend Extend, Zimmer Dental). Cell survival was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) after 24, 48, and 72 h and 7 days. Furthermore, morphology and adhesion of cells on the membrane were evaluated after 1 and 7 days by electron microscopy (scanning electron microscopy [SEM]). Statistical analysis was performed using two-way ANOVA with a significance level of 0.05. RESULTS: Based on the results of MTT, cell survival on HP and PP membranes after 7 days significantly increased (P < 0.001), but for the GC membrane, it was reduced after 7 days (P = 0.031). Cell survival on HP and PP membranes did not differ (P = 1) and was more than GC (P < 0.001). SEM images showed that the adhesion of cells was better on HP and PP membranes than GC. CONCLUSION: The results of this study showed that natural collagen membranes (HP and PP) similarly support proliferation and adhesion of gingival fibroblasts. Survival and adhesion of gingival fibroblasts on cross-linked collagen membrane was less than two other membranes.