Short (6 mm) and Regular Dental Implants in the Posterior Maxilla-7-Years Follow-up Study

Allogenic Bone Graft in Dentistry: A Review of Current Trends and Developments

In an effort to prepare non-autologous bone graft or biomaterial that would possess characteristics comparable to autologous bone, many different allogenic bone derivatives have been created. Although different existing processing methods aim to achieve the very same results, the specific parameters applied during different stages material preparation can result in significant differences in the material's mechanical and biological properties The properties, including osteoconductive, osteoinductive, and even osteogenic potential, can differ vastly depending on particular preparation and storage techniques used. Osteogenic properties, which have long been thought to be characteristic to autogenic bone grafts only, now seem to also be achievable in allogenic materials due to the possibility to seed the host's stem cells on a graft before its implantation. In this article, we aim to review the available literature on allogenic bone and its derivatives as well as the influence of different preparation methods on its performance.

Comparative evaluation of short or standard implants with different prosthetic designs in the posterior mandibular region: a three-dimensional finite element analysis study

The purpose of this study is to evaluate the stress distribution of splinted or nonsplinted restorations supported by 2 short or 2 standard dental implants in the mandibular molar region using three-dimensional finite element analysis. Two standard implants (4.8 × 10mm) were placed in the mandibular molar area. Two short implants (4.8 × 6 mm) were located in the mandibular molar atrophied area. Implant-supported prostheses were simulated with splinted or nonsplinted crowns design. Vertical load of 200 N and oblique load of 100 N were applied on the central fossa and the buccal cusps. Evaluation of stress distribution in implants and peri-implant cortical bone using the finite element analysis software (Ansys, Version 2020, R2), a multipurpose computer design program. The maximum principal stress of cortical bone around the implants was higher in nonsplinted crowns when compared to splinted crowns. The stress concentration of cortical bone surrounding implants increased as the implant length decreased either splinted crowns or nonsplinted crowns. The short implants with nonsplinted crowns showed lower stresses when compared to standard implants with nonsplinted crowns. The results suggest that the nonsplinted prostheses supported by short dental implants might be considered in the molar area of the atrophic mandible.

An Experimental Anodized and Low-Pressure Oxygen Plasma-Treated Titanium Dental Implant Surface-Preliminary Report

Chemical composition and physical parameters of the implant surface, such as roughness, regulate the cellular response leading to implant bone osseointegration. Possible implant surface modifications include anodization or the plasma electrolytic oxidation (PEO) treatment process that produces a thick and dense oxide coating superior to normal anodic oxidation. Experimental modifications with Plasma Electrolytic Oxidation (PEO) titanium and titanium alloy Ti6Al4V plates and PEO additionally treated with low-pressure oxygen plasma (PEO-S) were used in this study to evaluate their physical and chemical properties. Cytotoxicity of experimental titanium samples as well as cell adhesion to their surface were assessed using normal human dermal fibroblasts (NHDF) or L929 cell line. Moreover, the surface roughness, fractal dimension analysis, and texture analysis were calculated. Samples after surface treatment have substantially improved properties compared to the reference SLA (sandblasted and acid-etched) surface. The surface roughness (Sa) was 0.59-2.38 µm, and none of the tested surfaces had cytotoxic effect on NHDF and L929 cell lines. A greater cell growth of NHDF was observed on the tested PEO and PEO-S samples compared to reference SLA sample titanium.

Soft-Tissue Augmentation around Dental Implants with a Connective Tissue Graft (CTG) and Xenogeneic Collagen Matrix (CMX)-5-Year Follow-Up

Proper horizontal and vertical thickness of the gingival connective tissue has been proven to be one of the success criteria in dental implant and reconstructive surgery. When thin tissue is found, gingiva augmentation methods can be used to increase the quality and volume of the tissue. Many methods have been described, among them pedicle soft-tissue flaps or autogenic tissue grafts. As an alternative to patients' own tissue, xenogenic materials can be used for grafting. The fundamental issue is to choose a material that will ensure the maximum therapeutic effect, while also minimizing the negative influence on the patient's health. The aim of this study was to compare gingival augmentation procedures using a palatal connective tissue graft (CTG) and an xenogenic soft-tissue substitute, Geistlich Mucograft (xenogeneic collagen matrix; CMX), and assess whether the timing of the graft surgery influences the clinical outcomes. The original study was a randomized control trial with a total of 75 implants placed. The patients received the soft-tissue thickening 3 months before the implant placement or 3 months after the implant placement (depending on the group). A connective tissue graft (CTG) or Geistlich Mucograft were used (depending on the group). For both the CTG and Geistlich Mucograft, better clinical outcomes were observed for maintaining the alveolar bone level and the thickness of the attached gingiva compared to the control group with no gingival augmentation. The Geistlich Mucograft showed good clinical performance in comparison to the control. Soft-tissue augmentation with the CTG before the implant placement was found to be most efficient method in terms of a stable increase of the tissue thickness since, throughout the entire observation period, the greatest increase of 1.035 mm (SD = 0.73 mm) in thickness was observed. Statistically important differences in the tissue thickness baseline compared after 5 years were observed for groups G1 vs. G2b (no augmentation vs. CTG before), G1 vs. G3b (no augmentation vs. CTG after) and for groups G2b vs. G3a (CTG before vs. CMX after).

Survival of surface-modified short versus long implants in complete or partially edentulous patients with a follow-up of 1 year or more: a systematic review and meta-analysis

PURPOSE

Short implants are a potential alternative to long implants for use with bone augmentation in atrophic jaws. This meta-analysis investigated the survival rate and marginal bone level (MBL) of surface-modified short vs. long implants.

METHODS

Electronic and manual searches were performed for articles published between January 2010 and June 2021. Twenty-two randomized controlled trials (RCTs) comparing surface-modified short and long implants that reported the survival rate with at least 1 year of follow-up were selected. Two reviewers independently extracted the data, and the risk of bias and quality of evidence were evaluated. A quantitative meta-analysis was performed regarding survival rate and MBL.

RESULTS

The failure rates of surface-modified short and long implants differed significantly (risk ratio, 2.28; 95% confidence interval [CI], 1.46, 3.57; P<0.000). Long implants exhibited a higher survival rate than short implants (mean follow-up, 1-10 years). A significant difference was observed in mean MBL (mean difference=-0.43, 95% CI, -0.63, -0.23; P<0.000), favoring the short implants. Regarding the impact of surface treatment in short and long implants, for hydrophilic sandblasted acid-etched (P=0.020) and titanium oxide fluoride-modified (P=0.050) surfaces, the survival rate differed significantly between short and long implants. The MBL differences for novel nanostructured calcium-incorporated, hydrophilic sandblasted acid-etched, and dual acid-etched with nanometer-scale calcium phosphate crystal surfaces (P=0.050, P=0.020, and P<0.000, respectively) differed significantly for short vs. long implants.

CONCLUSIONS

Short surface-modified implants are a potential alternative to longer implants in atrophic ridges. Long fluoride-modified and hydrophilic sandblasted acid-etched implants have higher survival rates than short implants. Short implants with novel nanostructured calcium-incorporated titanium surfaces, hydrophilic sandblasted acid-etched surfaces, and dual acid-etched surfaces with nanometer-scale calcium phosphate crystals showed less marginal bone loss than longer implants. Due to high heterogeneity, the MBL results should be interpreted cautiously, and better-designed RCTs should be assessed in the future.

TRIAL REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO) Identifier: CRD42020160185.

The role of folded fibular flap in patients' reconstruction of mandibular defects: a retrospective clinical study

This study has analyzed 41 patients with mandibular ameloblastoma who underwent a partial mandibulectomy and reconstruction by folding the free fibular flap. In the preoperative and postoperative (6 months and 24 months after surgery), the Quality of Life (QOL) of these patients was assessed by using the University of Washington Quality of Life Questionnaire (UW-QOL) and the medical outcome study short form-36 (SF-36) questionnaires. SPSS 20.0 statistical software was used to conduct statistical analysis on the base data of the two groups of patients. Independent sample t test was conducted for sf-36 and UW-QOL scores at two time points in each group. The SF-36 survey showed that body pain (54.54 ± 8.10), general health (55.27 ± 7.54), and health changes (58.29 ± 9.60) decreased significantly at 6 months after surgery, but the mean score at 24 months after surgery all exceeded the preoperational level. At 24 months after the surgery, the vitality (80.41 ± 3.74), social function (81.61 ± 4.07), emotional role (82.39 ± 4.07), psychological health (81.66 ± 4.37) and total score (704.00 ± 31.53) all returned to the preoperative level, which was statistically significant compared with 6 months after surgery. However, there was no significant difference compared with the preoperative level. The UW-QOL survey showed that chewing (56.68 ± 7.23), speech (54.54 ± 7.7) and taste (62.29 ± 10.15) have significantly changed at 6 months after the surgery, and the difference was statistically significant at 24 months after surgery. Saliva generation decreased slightly (80.76 ± 3.35) at 6 months after surgery, but quickly returned to the preoperative level (81.59 ± 4.06). The total score of the patients almost recovered to the preoperative level at 24 months after surgery. The folded the fibular flap can not only repair the defects of soft tissue and bone tissue, but also restore the height of the alveolar ridge to, avoid the imbalance of crown and root ratio after implantation and reduce the occurrence of peri-implant inflammation, so that a true functional reconstruction can be realized.

Preliminary Study with the Use of a Titanium Mesh as Space Maker and Implant Primary Stabilization for One-Stage Sinus Lift in Cases with Less Than 1.5 mm Residual Bone

(1) Background: In the lateral area of the maxilla, the alveolar bone can lose significant volume due to maxillary sinus pneumatization following teeth extractions. This preliminary study evaluated the effectiveness of a novel technique for one-stage sinus lifting and simultaneous implant placement in cases with less than 1.5 mm residual alveolar bone. The subsequent survival rate at 1-year post-occlusal loading was assessed. (2) Methods: 15 patients were selected, the main inclusion criteria were the partially edentulous area in the posterior maxilla with alveolar bone height of less than 1.5 mm below the sinus. All of the patients underwent one-stage sinus lifting, along with simultaneous implant placement using a “butterfly” anchorage device to optimize the primary stability and xenograft bone as graft material. At 6 to 9 months after surgery, the anchorage device was removed and implants were loaded. Panoramic x-ray images were used to assess the new bone formation, while the biological stability was measured using resonance frequency analysis. (3) Results: 15 implants were inserted. The mean implant stability quotient (ISQ) value was 71.3 (SD = ±2.51) and the mean healing period was 7.3 (SD = ±1.23) months. The mean bone height after the healing period was 14.4 (SD = ±2.05). A statistically significant correlation was found between the healing period and the ISQ value (Spearman rho = 0.684, sig. = 0.005). No statistically significant correlation was found between the ISQ value and the new regenerated bone height (Person r = 0.389, sig. = 0.152). Smoking was identified as a risk factor involved in postoperative complications. (4) Conclusions: The results of the present preliminary study demonstrated that the proposed “butterfly” technique was effective when performing one-stage sinus lifting and simultaneous implant placement in cases with less than 1.5 mm of residual alveolar bone. The survival rate was 100% at 1-year post occlusal loading.

Clinical Outcome of Dental Implants after Maxillary Sinus Augmentation with and without Bone Grafting: A Retrospective Evaluation

(1) Background: The purpose of the present study was to retrospectively evaluate and compare the outcome of two sinus augmentation grafting protocols using a xenograft or blood clot alone over a 72-month follow-up. (2) Methods: Patients who received simultaneous lateral sinus floor augmentation and implant placement were included. Subjects were divided into two groups according to the grafting material, namely xenograft or blood clot, and into sub-groups based on the residual alveolar bone height (RABH) below the maxillary sinus, namely 4 to 6 mm or >6 mm. Kaplan-Meier survival estimates were calculated for each material group and for each sub-group at 1, 3, and 6 years. (3) Results: In total, 289 implants inserted in 136 patients with a one-stage procedure were considered. A total of 35 failures were registered. Overall survival rates were 94.2% for xenograft and 85.9% for blood clot alone at 1 year, 91.1% and 81.6% at 3 years, and 91.1% and 78.7% at 6 years. (4) Conclusions: In patients with 4-6 mm RABH, graftless interventions exploiting blood clot alone were not as successful as those using xenograft. When the RABH is low, sinus floor augmentation associated with grafting materials should be preferred whenever possible.