Biomechanics and Derangements of the Temporomandibular Joint

Evaluation of the effectiveness of dextrose injection in improving chewing function in patients with the temporomandibular joint closed lock: a pilot study

OBJECTIVE

To evaluate the intra-articular injection of 5% Dextrose efficacy in treating difficulty chewing patients with Temporomandibular Joint (TMJ) Closed Lock (CL).

MATERIALS AND METHODS

This pilot study included twenty female patients suffering from symptoms of Disc Displacement without Reduction (DDwoR) with limited mouth opening (Closed Lock) mentioned in the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Participants were randomly assigned into two groups; the study group patients were injected with D5W, while the control group patients were injected with 0.9% normal saline. The chewing Pain Index (CPI) was measured based on the criteria recommended by the International Association of Oral and Maxillofacial Surgeons (IAOMS) that assessed mandibular function by relating pain with the type of food eaten and using it as an index of improvement in function. The CPI was measured before and thrice after injection (2 weeks, 2 months, and 6 months). The significance level was set at α = 0.05.

RESULTS

A decrease in the CPI grades was observed in both groups, with a significant difference in favor of the study group at all follow-up times(< 0.001).

CONCLUSION

D5W improved the chewing function in female closed-lock patients.

Comprehensive review of polyetheretherketone use in dentistry

PURPOSE

This study aimed to comprehensively summarize the current state, shortcomings, and challenges regarding the use of polyetheretherketone (PEEK) in various fields of stomatology.

STUDY SELECTION

This study reviewed articles retrieved from PubMed, Google Scholar, Web of Science, and ScienceDirect databases. The main keywords used during the search included "polyetheretherketone (PEEK)," "dental materials," "orthodontics," "prosthodontics," "oral implantology," "oral and maxillofacial surgery," "periodontics" "osseointegration," and "surface modification."

RESULTS

Numerous studies have highlighted the properties of PEEK that contribute to its usefulness in dentistry, including its high biocompatibility, fracture resistance, aesthetics, radiolucency, and bone-like mechanical properties. Promising applications of PEEK in dentistry include orthodontic archwires, interceptive orthodontic appliances, fixed lingual retainers, crowns, post and cores, fixed partial dentures, removable partial dentures, maxillofacial prostheses, dental implants, implant abutments, alveolar bone scaffolds, jaw reconstruction, temporomandibular joint reconstruction, periodontal splints, and occlusal splints. In addition, many in vitro and in vivo experiments have demonstrated that the in vivo bone integration capability can be effectively improved using advanced surface modification technologies.

CONCLUSIONS

PEEK has been explored in several dentistry fields owing to its excellent properties. PEEK and its modifications are most frequently used in clinical dentistry. However, most of its applications are based on in vitro or short-term in vivo evaluations. Additional long-term clinical data are required to demonstrate the applicability and superiority of PEEK in dentistry.

A mechanoluminescent material, ZnS:Mn,Li, with enhanced brightness for visualizing dental occlusion

Mechanoluminescent materials are characterized by high luminescence intensity, high repeatability, no external voltage activation, and a good linear relationship between stress and mechanoluminescence intensity within a certain range. Therefore, mechanoluminescent materials have attracted increasing attention from researchers in the fields of stress sensing, encryption and anti-counterfeiting, structural health monitoring, energy-saving lighting, intelligent wearable devices, and other fields. In this study, ZnS:Mn powders with different Mn2+ ratios and different ion doping were synthesized by a high-temperature solid-phase reaction, and the synthesis of various materials was characterized. Then, the optimal mechanoluminescence effect of the ZnS:1%Mn,1%Li material was obtained. The photoluminescence intensity of ZnS:1%Mn,1%Li was 16.7 times higher than that of the sample without doping with Li+, and the mechanoluminescence intensity was 1.64 times higher. Finally, polyethylene terephthalate (PET) film was combined with ZnS:Mn,Li mechanoluminescent powders to prepare flexible three-layer composite film. Based on this, a feasible strategy for the detection of temporomandibular disorders was proposed. The composite film is easy to use, economical, and safe, and has good mechanoluminescent performance, which has potential application value in the field of occlusal force detection and visualization.

Assessment of the condylar response of two differently anchored fixed functional appliances in class II malocclusion in young adult orthodontic patients: A randomized clinical trial

OBJECTIVE

Measuring the condylar volume changes after treatment with skeletally anchored type IV Herbst appliance vs. Twin Force Bite Corrector (TFBC) in class II malocclusion in young adult patients.

MATERIALS AND METHODS

Twenty class II malocclusion participants were randomly involved in our randomized clinical study. They are divided equally into two groups: group I (10 patients with an age range of 16 to 18 years and a mean age of (17.15 ± 0.62) (five males and five females) with a mean Angle formed between (A) point and (Nasion) point and (B) point, to determine anteroposterior relation between maxilla and mandible (ANB) of 6.20 (1.03) and a mean mandibular length of 106.1 (1.7), who were treated by a skeletally anchored type IV Herbst appliance, supported at the mandible by two mini-plates fixed bilaterally at the mandibular symphysis; group II (10 patients with an age range of 15 to 18 years and a mean age of (16.85 ± 0.33) (six males and four females) with a mean ANB of 6.80 (0.89) and a mean mandibular length of 107.3 (2.36), who were treated by a TFBC that was installed just mesial to the tube of the maxillary first permanent molar and distal to the bracket of the lower canine for 4 months. According to the Index of Orthognathic Functional Treatment Need (IOFTN) index, the participants in both groups have grade 4 (great need for treatment) as they have excessive overjet (6-9 mm). Cone-beam computed tomography (CBCT) was taken just before installing fixed functional appliances and after the removal. The condylar volume was measured using Dolphin software. Parametric measurements were performed by the independent t-test, while non-parametric variables (percent change) were compared by the Mann-Whitney U-test.

RESULTS

On the right side, the Herbst group recorded a percent increase (median = 1.23%), while TFBC recorded a median percent decrease (-7.85%). This change is statistically significant (P = 0.008).

CONCLUSIONS

The difference in the condylar volume was significantly higher with the mini-plate anchored Herbst appliance than with the dentally anchored TFBC group.