Clinical efficacy of melatonin as adjunctive therapy to non-surgical treatment of periodontitis: a systematic review and meta-analysis.

OBJECTIVE: This study aimed to evaluate the effect of adjunctive melatonin supplementation on clinical outcomes after non-surgical periodontal treatment. METHODS: PubMed, Embase, and Web of Science databases were systematically searched for randomised controlled trials (RCTs) of melatonin adjuvant therapy for periodontitis from inception until May 2021. The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and registered on The International Prospective Register of Systematic Reviews (PROSPERO) (CRD42021250630). The risk of bias of included studies was assessed according to the Cochrane Handbook for Systematic Reviews of Interventions. The pooled effect estimates were calculated by a random-effects model, and results were expressed as weighted mean differences (WMD). RESULTS: Seven RCTs comprising 412 participants were included in the meta-analysis. The pooled results showed that adjuvant use of melatonin for non-surgical periodontal treatment significantly improved the probing depth (PD) [WMD = - 1.18, 95% CI (- 1.75, - 0.62) I2 = 85.7%], clinical attachment loss (CAL) [WMD = - 1.16, 95% CI (- 1.60, - 0.72) I2 = 76.7%] and gingival index (WMD = - 0.29, 95%CI [- 0.48, - 0.11], I2 = 63.6%) compared with non-surgical treatment alone. In addition, subgroup analysis showed that higher doses of melatonin (3-10 mg) significantly improved PD [WMD = - 1.32, 95%CI (- 2.31, - 0.15) I2 = 93%] and CAL [WMD = - 1.30, 95%CI (- 1.80, - 0.81) I2 = 73.7%] compared with lower doses of melatonin (< 3 mg). CONCLUSIONS: We found that adjunctive melatonin supplementation can significantly improve the periodontal status after non-surgical treatment, suggesting that melatonin may be a new adjuvant therapy for periodontitis when non-surgical periodontal treatment alone cannot achieve the desired improvement.

[Study on the compatibility of yttria-stabilized zirconia framework bonded to the corresponding veneering ceramic].

OBJECTIVE: To investigate the bonding properties and interface characterization of a domestic 3mol yttrium-stabilized tetragonal zirconium polycrystal (3Y-TZP) framework fired on with 4 different veneering ceramics for zirconia. METHODS: 4 different commercial veneering ceramics for zirconia (VITA VM9, SHOFU VINTAGE ZR, IPS e.max Ceram, Cercon ceram kiss) were sintered on 3Y-TZP rectangulars (15 mmx5 mmx5 mm) according to the manufacturers' instructions for shear bond strength test, a metal-ceramic system(Ni-Cr alloy/VITA VMK95) was fabricated in the same type as a control group. Two bilayered specimens (3Y-TZP/VITA VM9, Ni-Cr/VMK95) were prepared for scanning electron microscope (SEM) and energy distribution spectrum (EDS). RESULTS: The values of shear bond strength test were (18.83 +/- 1.77) MPa for 3Y-TZP/VITA VM9, (23.83 +/- 7.05) MPa for 3Y-TZP/SHOFU VINTAGE ZR, (17.87 +/- 2.30) MPa for 3Y-TZP/IPS e.max Ceram, (22.26 +/- 7.45) MPa for 3Y-TZP/Cercon ceram kiss, (20.55 +/- 5.13) MPa for Ni-Cr alloy/VITA VMK95. There was no statistically significant between all-ceramic groups and the control group (P > 0.05). The failure modes in all-ceramic groups showed predominately adhesive at the interface. SEM showed the 3Y-TZP/VITA VM9 contacted tightly at the interface, while EDS detected Si element diffused into 3Y-TZP material. CONCLUSION: The results indicate that domestic 3Y-TZP has a good interface compatibility with 4 commercial veneering ceramics, as a dental framework material, it can satisfy the clinical requirements.

[The ultrastructure and activities of free radical scavenger in discolored gingiva adjacent to porcelain fused to metal crowns].

PURPOSE: This study was designed to study the discolored gingiva adjacent to porcelain fused to metal (PFM) crowns in terms of ultrastructure , SOD and GSH activities in 40 cases. METHODS: The discolored gingival ultrastructures were observed and metal X-ray energy level was analyzed;The activities of SOD and GSH were measured and compared with normal control by student's t test and one-way ANOVA with SPSS10.0 software package. RESULTS: The discolored gingival ultrastructure had changes compared with the normal gingiva. Nickel and chromium were not found in the particles through X-ray energy machine within the discolored gingiva adjacent to PFM crown. The activities of SOD and GSH in discolored gingiva were significantly different from control(P<0.05) and the values at 6 to 18 months were significantly different from those at other times. CONCLUSION: The ultrastructure underwent changes in discolored gingiva after PFM restoration; the activity of SOD and GSH in discolored gingiva changed to result in apoptosis, and discoloration.