Objective: This systematic review aimed to assess the efficacy of occlusal splints in the treatment of temporomandibular disorders (TMDs). Material and Methods: This systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Four databases (Medline via Pubmed, Web of Science, Embase and Scopus) were searched, the last search was conducted on April 2020. Randomised controlled trials (RCTs) employing the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) or Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) as diagnostic criteria and including occlusal splint as one of the experimental groups were included in the present study. The data from the included studies were extracted and assessed for risk of bias. Results: Eleven studies were included. The sample size ranged from 12 to 96 subjects. The male to female ratio was 0 to 25%. The mean length of follow-up was 4 months. Occlusal splint had a positive effect on mandibular movements in all included studies. Seven studies showed a positive effect of occlusal splint on chronic pain reduction and pain intensity, while two others showed improvement of temporomandibular joint clicking sounds and locking of the jaws. Moreover, improvements in mouth opening, depression, and anxiety symptoms, were reported in four studies. Conclusions: An occlusal splint can be considered as a non-invasive treatment approach for patients with TMD, especially those with signs and symptoms of restriction of mandibular movement and pain. Moreover, the present findings highlighted an urgent need of a standardised consensus regarding the prognostic evaluation of TMD.

Objectives: To compare the accuracy of dynamic navigation (DN) with a static surgical guide (SSG) for dental implant placement and the influence factors such as the experience of the surgeon and the implant sites.Methods and materials: A total of 38 implants, which underwent the dynamic navigation,and 57 implants which underwent a static surgical guide were enrolled in the retrospective study. Coronal deviation, apical deviation, and angular deviation were compared between the DN and SSG groups, along with the different experience level of surgeons and implant sites in the DN group.Results: There were no statistically significant differences between the DN and SSG groups, and the experience level of the surgeons and implant sites in the DN group. However, the apical deviation of the DN was slightly higher than the SSG group in the anterior teeth (P= 0.028), and the angular deviation of DN was smaller than the SSG group in the molar.Conclusion: Dynamic navigation can achieve accurate implant placement as well as the static surgical guide. Additionally, the experience level of the surgeon and implant site do not influence the accuracy of dynamic navigation, while the accuracy of DN seems higher than the SSG in molar.

The influence of angled abutments on stress is a matter of debate. It is widely accepted that increased stress on implants and bone has been associated with the use of angled abutments. However, comparisons of clinical success rates of implants restored with angled and straight abutments indicate no significant differences. The aim of the present study was to determine whether angled abutments could result in decreased stress on surrounding bone of single-unit dental implants. By means of finite element analysis (FEA), four simplified models were designed to simulate clinical scenarios in which that implants were placed in an ideal axial position or at an angled position. Each implant was paired with a straight or angled abutment. A simulated occlusal load of 100 N was applied along the vertical axis of the jawbone. The von Mises stress and strain were recorded for each model. The numerical results showed that angled abutments resulted in decreased stresses when implants were not placed in ideal axial position. The present study identified by means of FEA that angled abutments could result in decreased stress on the supporting bone of implant system and may provide some clues to resolve the debate regarding the influence of angled abutments.

Due to the rising demand for zirconia (Zr) based implant systems, it is important to understand the impact of Zr and titanium (Ti) implants and particularly their topography on soft tissue healing. As human gingival fibroblasts (hGFs) are the predominant cells in peri-implant soft tissue, we focused on examining the effect of implant material and surface roughness on hGFs’ initial attachment, growth and the expression of proteins involved in the focal adhesion. hGFs isolated from eight healthy donors were cultured on the following surfaces: smooth titanium machined surface (TiM), smooth zirconia machined surface (ZrM), moderately rough titanium surface (SLA), or moderately rough zirconia surface (ZLA) for up to 14 days. The initial attachment of hGFs was evaluated by scanning electron microscopy. Cell proliferation/viability was assessed by cell counting kit 8. Focal adhesion and cytoskeleton were visualized by a focal adhesion staining kit. The gene expression of focal adhesion kinase (FAK), α-smooth muscle actin (α-SMA), and integrin subunits ITG-β1, ITG-β4, ITG-α4, ITG-α5, ITG-α6, was evaluated by qPCR. Cell proliferation/viability was slightly decreased by moderately rough surfaces, whereas no effect of surface material was observed. Cell morphology was strikingly different between differently treated surfaces: on machined surfaces, cells had elongated morphology and were attached along the grooves, whereas on moderately rough surfaces, cells were randomly attached. Surface roughness had a more pronounced effect on the gene expression compared to the surface material. The expression of FAK, α-SMA, ITG-β4, ITG-α5, and ITG-α6 was enhanced by moderately rough surfaces compared to smooth surfaces. Within the limitations of this in vitro study, it can be concluded that the behavior of primary hGFs is primarily affected by surface structure, whereas no apparent advantage of Zr over Ti could be observed.