Effects of Low-Level Laser Therapy on Osseous Defects Distal to Mandibular Second Molar after Extraction of Impacted Third Molar.

Objective: To evaluate the efficiency of low-level laser therapy on the distal osseous defects of the mandibular second molar (M2) after the adjacent impacted third molar (M3) extraction. Methods: A total of 59 clinic cases were screened out, whose M3 were impacted and the distal alveolar bone of M2 had been destroyed horizontally. They were randomly divided into 2 groups based on whether they would have laser irradiation or not after M3 extraction. Then, postoperative complications of the 2 groups were compared. The alveolar bone level distal to M2 was established before and 3 to 6 months after M3 extraction by radiographic evaluation, which was compared between two groups. Results: The incidence of severe pain and mouth-opening limitation was significantly lower in the LLLT group than that in the control group. The amount of bone formation in the LLLT group was higher than that in the control group 3 months after the operation, and the difference was statistically significant. But the difference was not statistically significant 6 months after surgery. Conclusion: LLLT may alleviate postoperative complications and improve early osteogenesis. It is a viable option for use in the treatment of osseous defects distal to mandibular second molars following extraction of impacted third molars.

[Evaluation of the effect of Er:YAG laser combined with guided bone regeneration in the treatment of peri-implantitis with osseous defects].

PURPOSE: To evaluate the clinical benefits of Er:YAG laser combined with guided bone regeneration (GBR) in the treatment of peri-implantitis-assocaited osseous defects. METHODS: Twenty-six patients (34 implants in total) who underwent implant restoration in Dental Disease Prevention and Treatment Institute, Jiading District, from 2017 to 2019 and were diagnosed with peri-implantitis with osseous defects, and randomly divided into the experimental group and control group. The two groups of patients received open flap surgery, debridement and GBR treatment. The only difference in the experimental group was the use of Er: YAG laser to modulate and remove inflammatory tissue as well as to decontaminate the implant surface, instead of traditional mechanical treatment in the control group. The probing depth (PD), bleeding on probing (BOP), and plaque index (PI), the height of the bone defect around the implant (reduce of marginal bone level, RBL) were recorded and compared. SPSS 20.0 software package was used to analyze the data. RESULTS: The PD, BOP, PI and RBL of the two groups of patients were significantly improved after treatment with different methods. There was no significant difference in the improvement of PD, BOP and PI between the two groups 6, 12 and 24 months after treatment, while the improvement of RBL in the experimental group was significantly better than that of the control group 12 and 24 months after treatment. CONCLUSIONS: In the treatment of GBR with peri-implantitis and osseous defects, Er: YAG laser therapy is more effective than traditional mechanical methods, and is more conducive to the regeneration of new bone.

Advances in functionalized polymer coatings on biodegradable magnesium alloys - A review.

Magnesium (Mg) and its alloys have become a research frontier in biodegradable materials owing to their superior biocompatibility and excellent biomechanical compatibility. However, their high degradation rate in the physiological environment should be well tackled prior to clinical applications. This review summarizes the latest progress in the development of polymeric coatings on biodegradable Mg alloys over the last decade, regarding preparation strategies for polylactic acid (PLA), poly (latic-co-glycolic) acid (PLGA), polycaprolactone (PCL), polydopamine (PDA), chitosan (CS), collagen (Col) and their composite, and their performance in terms of corrosion resistance and biocompatibility. Feasible perspectives and developing directions of next generation of polymeric coatings with respect to biomedical Mg alloys are briefly discussed. STATEMENT OF SIGNIFICANCE: Magnesium (Mg) and its alloys have become a research frontier in biodegradable materials owing to their superior biocompatibility and suitable biomechanical compatibility. However, the principal drawback of Mg-based implants is their poor corrosion resistance in physiological environments. Hence, it is vital to mitigate the degradation/corrosion behavior of Mg alloys for safe biomedical deployments. This review summarizes the latest progress in development of polymeric coatings on biomedical Mg alloys regarding preparation strategy, corrosion resistance and biocompatibility, including polylactic acid (PLA), poly (latic-co-glycolic) acid (PLGA), polycaprolactone (PCL), chitosan (CS), polydopamine (PDA), collagen (Col) and their composite. In addition, functionalized polymer coatings with Mg alloys exhibits a promising prospect owing to their ability of degradation along with biocompatibility, self-healing, drug-delivery and osteoinduction.

[Quantitative analysis of nFA/PEEK implant interfaces in Beagle dogs].

PURPOSE: A new synthetic nano-fluorapatite poly-ether-ether-ketone (nFA/PEEK) dental implant in screw type was developed and its biocompatibility and osseointegration ability were evaluated in Beagle dogs. METHODS: Ten sandblasted and 10 non-sandblasted nFA/PEEK implants were placed in 6 adult Beagle dogs and the bilateral mandibular second and third premolar was extracted and the wounds were healed over 3 months. Three dogs were randomly chosen and executed at the end of 8th and 12th week. To evaluated bone to implant contact(BIC) and mineral apposition rate(MAR), tetracycline was intramuscularly given twice at 10th and 3rd day, before sacrifice respectively. The implants and the surrounding bone as a whole were collected and examined by synchrotron radiation tomography. Undecalcified implant and bone specimens were cut and stained by Van Gieson for a static histomorphometric analysis. The data was analyzed using SPSS18.0 software package. RESULTS: The implants were demonstrated by synchrotron radiation and connected to most of their bone beds at 8th week. Some new bones were developed into threads of screw implants, while complete osseointegration were noted at 12th week. Sandblasted implants were found to be faster matured. BIC and MAR of sandblasted group (63.34%, 1.51 µm/d) were significantly higher than that of non-sandblasted group (22.97%, 1.34 µm/d) (P<0.05) at 8th week. BIC of sandblasted group (75.49%) was significantly higher than that of non-sandblasted (55.35%) (P<0.05) at 12th week, while MAR was not significantly different between the 2 groups (1.28 µm/d versus 1.27 µm/d). The static parameters showed that bone volume fraction (BV/TV) and trabecular number (Tb.N) of sandblasted group were significantly higher than that of non-sandblasted group, while trabecular spacing (Tb.Sp) was significantly lower (P<0.05); No significant difference was found in trabecular thickness (Tb.Th) between 2 groups (P>0.05). The sandblasting group was more conductive to increase their bone mass. CONCLUSIONS: Sandblasted synthetic polymer's biomaterial nFA/PEEK has excellent biocompatibility and osteogenic properties, which is better osseointegrated to its bone bed. It will be a promising material as dental implants in the future.