ObjectivesTo overview preclinical animal trials and quantify the effect size that stem cell therapy has on the regeneration of periodontal tissue complex.Material and MethodsA systematic MEDLINE (PubMed) online library search was conducted for preclinical animal studies in vivo, using autologous periodontal ligament, dental pulp, cementum, alveolar periosteal, gingival margin or adipose stem cell types for periodontal tissue complex regeneration purposes. Studies had to be published between 2007.09.01 and 2017.09.01 in the English language.ResultsOnline library search yielded 2099 results. After the title, abstract and full-text screening ten studies fit inclusion criteria and were pooled into meta-analysis. Overall the stem cell regenerative therapy had a statistically significant positive influence on the periodontal tissue regeneration when compared to the control groups. The biggest influence was made to the regeneration of cementum (standardised mean difference [SMD] 2.25 [95% confidence interval (CI) = 1.31 to 3.2]) while the smallest influence was made to the alveolar bone (SMD 1.47 [95% CI = 0.7 to 2.25]) the effect size for periodontal ligament regeneration was (SMD 1.8 [95% CI = 1 to 2.59]). Subgroup analysis showed statistically significant (P < 0.05) differences between different cell types in the alveolar bone and cementum regeneration groups and in alveolar bone group in relation to scaffold materials.ConclusionsStem cell therapy has a positive impact on periodontal tissue complex regeneration. Such therapy has the biggest influence on cementum regeneration meanwhile alveolar bone regeneration is influenced by the least amount. However more and less diverse preclinical studies are needed to have a greater statistical power in future meta-analyses.

Background One of the main tasks of dental implantation is the precise insertion of the implant into the edentulous jaw. The purpose of a study was to determine the accuracy of implants inserted using static implantation guides in different conditions.Methods A search for clinical studies was performed in the PubMed databasis. The implantation procedure had to be performed on humans in vivo by using a static surgical guide. Pre and postsurgical CT scans were compared to evaluate the deviation of implants. A meta-analyses was performed to calculate the mean implant collar, apex, depth and axis deviations. A meta-regression analyses was performed by grouping study subgroups according to the method of surgery, implant insertion, jaw, guide support tissue, and the method of guide fixation.Results 19 studies were included in the meta-analysis. Data on 1872 implants were analyzed. Mean deviation was 1.25 mm (95% CI: 1.00, 1.51) at the implant entry point and 1.52 mm (95% CI: 1.18, 1.86) at the apex. Mean axis deviation was 3.47o (95% CI: 3.01, 3.94). Depth deviation was 0.15 mm (95% CI: -0.36, 0.66). The following factors had a positive influence on the implant precision: open surgical technique, fully guided implant insertion and fixation of the surgical guide.Conclusions The surgical technique, implant insertion method, jaw, guide supporting tissue and fixation has an effect on the deviation of inserted implants.