Strategies and Challenges in the Treatment of Dental Enamel.

Enamel tissue, the hardest body tissue, which covers the outside of the tooth shields the living tissue, but it erodes and disintegrates in the acidic environment of the oral cavity. On the one hand, mature enamel is cell-free and, if damaged, does not regenerate. Tooth sensitivity and decay are caused by enamel loss. On the other hand, the tissue engineering approach is challenging because of the unique structure of tooth enamel. To develop an exemplary method for dental enamel rebuilding, accurate knowledge of the structure of tooth enamel, knowing how it is created and how proteins interact in its structure, is critical. Furthermore, novel techniques in tissue engineering for using stem cells to develop enamel must be established. This article aims to discuss current attempts to regenerate enamel using synthetic materials methods, recent advances in enamel tissue engineering, and the prospects of enamel biomimetics to find unique insights into future possibilities for repairing enamel tissue, perhaps the most fascinating of all tooth tissues.

The therapeutic effects of mesenchymal stem cells and their secretome on oral squamous cell carcinoma.

Oral cancers are prevalent in the human population, particularly in unindustrialized countries. In 90 % of oral cancers, the tumors arise from squamous cells, which is called oral squamous cell carcinoma (OSCC). Despite new treatment strategies, the morbidity and mortality rates are still high. Current treatment options including surgery, chemotherapy, and radiotherapy are not effective in the treatment of the tumor. Cell therapy with mesenchymal stem cells (MSCs) is considered one of the leading strategies in cancer treatment. However, the field of MSC therapy in OSCC is immature and ongoing studies are being conducted in experimental and pre-clinical studies. Here, we reviewed these studies to figure out whether the use of MSCs could be worthwhile in OSCC therapy or not. Both native and engineered MSCs as well as their secretome have been used in the treatment of OSCC. It seems that genetically modified MSCs or their secretome could inhibit the tumorigenesis of OSCC. However, further pre-clinical studies are required to come to a conclusion.

Evaluation of cannabinoid receptors type 1-2 in periodontitis patients.

BACKGROUND: As effective immune modulators, Endocannabinoids may suppress the inflammatory responses in periodontitis. This study assessed the expression of cannabinoid receptors in gingiva and the impact on periodontitis. METHODS: A cross-sectional study on 20 patients with more than stage II and Grade A periodontitis and a control group consisting of 19 healthy individuals was performed. The gingival biopsies were assessed for the expression of CB1 and CB2 using the quantitative reverse transcription polymerase chain reaction, TaqMan method. RESULTS: The study sample consisted of 39 subjects, 31 females (79.5%) and 8 males (20.5%), including 20 periodontitis subjects (80% female and 20% male), and control groups (78.9% female and 21.1% male). The mean ages of cases and controls were 33.3 ± 4.7 and 35.7 ± 5.1 years, respectively. The gene expression of CB2 in periodontitis was 27.62 ± 7.96 and in healthy subjects was 78.15 ± 23.07. The CB2 was significantly lower than the control group (p = .008). In comparison, the gene expression index of CB1 in the periodontal group (9.42 ± 3.03) was higher than the control group (6.62 ± 1.13) but did not meet a significant value (p = .671). CONCLUSION: The lower expression of CB2 receptors in the periodontitis group may be due to the reduced protective effect of anti-inflammatory agents. These elements include cannabinoids and the imbalance leading to the predominance of pro-inflammatory effects. Therefore, the local effects of cannabinoids as an immunomodulator could be useful for oral inflammatory diseases such as periodontitis.

Long-Term Effect of Keratinized Tissue Width on Peri-implant Health Status Indices: An Updated Systematic Review and Meta-analysis.

PURPOSE: The keratinized tissue (KT) around dental implants may be useful to ease plaque control. This meta-analysis aimed to compare peri-implant health parameters based on KT width (≥ 2 mm vs < 2 mm). MATERIALS AND METHODS: A highly sensitive search of five databases was performed up to February 1, 2020. The quality of eligible studies was assessed using a modified version of the Newcastle-Ottawa checklist. A random-effects model was used to pool standardized mean differences with 95% confidence intervals. To discover sources of heterogeneity, subgroup analysis and meta-regression were used. Publication bias was evaluated by the Egger and Begg tests. RESULTS: From 7,934 identified studies, 22 papers were included in the meta-analysis, representing 3,004 implants in the case group (KT ≥ 2 mm) and 1,829 implants in the control group (KT < 2 mm). The results indicated that most of the parameters, including gingival recession (GR), Gingival Index (GI), modified Gingival Index (mGI), Plaque Index (PI), modified Plaque Index (mPI), bleeding on probing (BOP), modified Bleeding Index (mBI), and bone loss (BL) revealed substantial differences between the control and case groups. On the contrary, no statistically significant association was detected for pocket depth (PD) between the two groups. CONCLUSION: The presence of at least 2 mm of KT around implants has a protective effect on the peri-implant tissue condition. Narrow KT was related to higher BL, BOP, mBI, GI, mGI, PI, mPI, and GR. In addition, with regard to PD, no significant difference was found.