The Effect of Topical Application of Hyaluronic Acid on the Stability of Immediate Loaded Dental Implants in the Posterior Maxilla: Clinical and Animal Study.

Objective: To assess the effect of topically applied hyaluronic acid (HA) on the stability of immediately loaded implants in the posterior maxilla. Materials and Methods: For the clinical study, a total of 20 implants were placed in 14 patients seeking the replacement of missing single or multiple posterior maxillary teeth. The patients were randomly divided into two groups. In the clinical control group (CC group), 10 implants were placed and immediately loaded, while in the clinical study group (CS group), 10 implants were coated with HA immediately before placement and immediately loaded. All patients had implant stability clinically evaluated at implant placement time (T0) and 1 (T1), 3 (T3), and 6 (T6) months after loading. Peri-implant pocket depth and modified sulcus bleeding index were evaluated clinically at 6 months in all patients. Bone density was evaluated radiographically after 3 months. All the clinical and radiographic data were subjected to statistical analysis. For the animal study, a total of 12 implants were placed in the tibiae of six rabbits. For each rabbit, 1 implant without any applied HA was placed in the left tibia (AC group), and 1 implant coated with HA was placed in the right tibia (AS group). The rabbits were euthanized at 21 and 45 days after implant insertion. Results: There were no significant statistical differences between the two groups regarding implant stability, peri-implant pocket depth, modified sulcus bleeding index, or bone density from the palatal and apical aspects. However, there was a significant statistical difference in the bone density from the buccal aspect in favor of the study group. The animal study showed that the newly formed bone in the right tibiae showed improved quantity and quality of bone, as it had denser bone trabeculae and smaller marrow spaces compared to the left tibiae. Conclusion: In the clinical study, the application of hyaluronic acid had a superior effect on the buccal bone density around immediately loaded implants. In the animal study, hyaluronic acid had a synergistic effect on the quality and quantity of bone formation around dental implants.

Impact of bone marrow mesenchymal stem cells on the submandibular gland structure of adult male albino rats exposed to cadmium chloride toxicity.

OBJECTIVE: This study was carried out in submandibular salivary glands of rats to demonstrate the changes induced by cadmium intoxication and the possible prophylactic and therapeutic effects of bone marrow mesenchymal stem cells (BMSCs). DESIGN: Sixty-five rats were divided into five groups. Rats in Group I were controls while those of Group II received daily dose of 10 mg/kg cadmium for 24 days. Rats in Group III received single prophylactic dose of 1 × 106 BMSCs one week before cadmium administration. Rats of Group IV were concomitantly administered cadmium and BMSCs, while those of Group V received cadmium for 24 days and were then treated with single dose of 1 × 106 BMSCs. Rats of Groups I, II, III, and IV were euthanized at the end of the experiment while those of Group V were euthanized one week later. Salivary gland specimens were processed and stained with H&E and inducible nitric oxide synthase; other specimens were used to demonstrate metallothionein gene expression using RT-PCR, malondialdehyde and catalase enzymes were detected by ELISA. RESULTS: Groups III and IV had nearly comparable findings to Group I regarding histological pattern with normal gland features. Group III recorded a lower fold of change for metallothionein gene (1.14 ± 0.20), a lower malondialdehyde enzyme (21.67 ± 1.63 nmol/mg), and a higher catalase enzyme (66.33 ± 2.16 mmol/mg). Regarding all variables, significant differences were found between the different groups (P < 0.001). CONCLUSION: BMSCs have prophylactic and therapeutic effects against cadmium-induced cytotoxicity in rat salivary glands.