牙周因素对种植体周围病影响机制的研究进展

随着种植义齿在临床修复中的广泛应用,种植修复后最常见的生物学并发症——种植体周围病的发生发展也引起了学者们的广泛关注。种植体周围病所导致的软组织破坏和骨组织吸收对种植体在口内的长期稳定、美观及功能产生不良影响,且目前尚缺乏有效的治疗手段。牙周炎作为种植体周围病发生发展的一个关键危险因素,会显著增加种植体周围病的发生风险,降低种植体的成功率。目前认为,种植体周围较差的软组织封闭、牙周炎症状态对口腔微生物环境和宿主免疫微环境两方面的影响,共同导致了种植体周围病的发生。文章就现有牙周因素与种植体周围病的分子学研究进行了回顾总结,对牙周因素影响种植体周围病发生发展的可能机制做一综述,以期在临床上为种植体周围病提供有效的防治策略。     

牙周炎患者种植义齿修复后口腔自我维护的临床观察

目的：观察菌斑显示剂在轻中度牙周炎稳定期进行种植义齿修复病例,预防早期种植体周围疾病中的作用。方法：对56例轻中度牙周炎稳定期病例进行种植义齿修复的患者,进行1年种植修复后的牙周维护,期间在患者进行口腔自我维护中使用菌斑显示剂,观察种植体周围黏膜炎的发生率。结果：种植修复后1年内两组种植体周围黏膜炎平均发生率分别为43．6％和58．3％,两组差异有统计学意义（x＝0．031,P＜0．05）。结论：系统口腔健康教育及良好的菌斑自我控制可以降低牙周炎患者种植体周围黏膜炎的发生。     

Influence of controlled immediate loading and implant design on peri-implant bone formation

AIM: Tissue formation at the implant interface is known to be sensitive to mechanical stimuli. The aim of the study was to compare the bone formation around immediately loaded versus unloaded implants in two different implant macro-designs. MATERIAL AND METHODS: A repeated sampling bone chamber with a central implant was installed in the tibia of 10 rabbits. Highly controlled loading experiments were designed for a cylindrical (CL) and screw-shaped (SL) implant, while the unloaded screw-shaped (SU) implant served as a control. An F-statistic model with alpha=5% determined statistical significance. RESULTS: A significantly higher bone area fraction was observed for SL compared with SU (p<0.0001). The mineralized bone fraction was the highest for SL and significantly different from SU (p<0.0001). The chance that osteoid- and bone-to-implant contact occurred was the highest for SL and significantly different from SU (p<0.0001), but not from CL. When bone-to-implant contact was observed, a loading (SL versus SU: p=0.0049) as well as an implant geometry effect (SL versus CL: p=0.01) was found, in favour of the SL condition. CONCLUSIONS: Well-controlled immediate implant loading accelerates tissue mineralization at the interface. Adequate bone stimulation via mechanical coupling may account for the larger bone response around the screw-type implant compared with the cylindrical implant.     

Soft tissue healing at titanium implants coated with type I collagen. An experimental study in dogs

Objective: To analyse the soft tissue healing at titanium implants coated with type 1 collagen. Material and methods: Six dogs were used. The mandibular pre‐molars and the three anterior maxillary pre‐molars were extracted. Three months later mucoperiosteal flaps were raised and two test and two control implants were installed (3i^® TG Osseotite^®3.75 × 10 and 2.8 mm transmucosal collar). The test implants were coated with a purified porcine type I collagen. Cover screws were placed and flaps were sutured. The sutures were removed 2 weeks later and a plaque‐control programme was initiated. Another 2 weeks later, the procedure was repeated in the contra‐lateral mandibular region. Four weeks after the second implant surgery, biopsies were obtained and prepared for histological examination. Results/Conclusion: The vertical dimensions of the epithelial and connective tissue components as well as the composition of the connective tissue portion facing the implant were similar at collagen‐coated and uncoated implants after 4 and 8 weeks of healing. It is suggested that soft tissue healing to implants coated with type I collagen was similar to that at non‐coated titanium implants and that no adverse reactions to the collagen‐coated implants occurred.     

Epstein–Barr Virus and Peri-Implantitis: A Systematic Review and Meta-Analysis

The exponential growth in the use of dental implants in the last decades has been accompanied by an increase in the prevalence of peri-implant disease. It appears that viruses may have pathogenic potential for the development of this pathology. The objective of this systematic review is to study the possible association between the presence of Epstein–Barr virus and the development of peri-implantitis. An electronic search was conducted in PubMed/MEDLINE, Scielo and Embase databases for cross-sectional and case–control studies in humans published up to and including 4 January 2021. Five studies were included in the qualitative analysis. The meta-analysis did not show a statistically significant difference regarding the prevalence of Epstein–Barr virus in the peri-implant sulcus between implants with peri-implantitis and healthy implants. In conclusion, no association between the human herpesvirus 4 and peri-implantitis was found. Further research on this topic is essential to develop more effective treatments.     

Subcrestal placement of two-part implants

Objective: The aim of the present experiment was to study the healing around two-part implants that were placed in a subcrestal position.
Material and methods: Five mongrel dogs, about 2 years old, were included. The mandibular premolars and the first, second and third maxillary premolars were extracted. Three months later two test and two control implants (OsseoSpeed^™, 3.5 mm × 8 mm) were placed in one side of the mandible. The implants were placed in such a way that the implant margin was located 2 mm apical to the bone crest. In the test implants, the surface modification extended to the implant margin and, thus, included the shoulder part of the implant. Regular abutments with a turned surface (Zebra^™) were connected to the control implants, while experimental abutments with a modified surface (TiOblast^™) were connected to the test implants. A plaque control program that included cleaning of implants and teeth every second day was initiated. Four months later the dogs were euthanized and biopsies were obtained and prepared for histological analysis.
Results: The marginal bone level at the test implants was identified in a more coronal position than that at the control implants. In 40% of the test implants, the bone-to-implant contact extended coronal of the abutment/fixture (A/F) border, i.e. in contact with the abutment part of the implant. The connective tissue portion of the peri-implant mucosa that was facing the test abutments contained a higher density of collagen and a smaller proportion of fibroblasts than that at the control sites.
Conclusion: It is suggested that osseointegration may occur coronal to the A/F interface of two-part implants. Such a result, however, appears to depend on the surface characteristics of the implant components.     

Microbiological and clinical effects of chlorhexidine enclosed in fixtures of 3I-Titamed implants

This double-blind study used a split-mouth design to investigate the microbiological and clinical effects of 0.2% chlorhexidine enclosed in fixtures. Twelve patients had 46 fixtures implanted. At second-stage surgery, a microbiological sample (baseline sample) of the inner parts of the fixtures was taken. Then, a 0.2% chlorhexidine solution was applied into the inner space of 23 fixtures (test group), and in 23 fixtures saline was applied (control group). Abutments were installed and gingival index, plaque index and crevicular fluid flow were monitored weekly. After 6 weeks, a second microbiological sample of the inner part of the fixtures was taken. At baseline, viable bacteria were detected within 46% of the fixtures. After weeks, bacteria were found in 87% of the fixtures. The numbers of bacteria in the control group were significantly higher than those in the test group. The results indicate that, after first-stage surgery, contamination of the inner spaces of the fixtures is commonplace. Application of a 0.2% chlorhexidine solution at second-stage surgery inhibits growth or acquisition of bacteria in the fixtures. In both test and control groups, the crevicular fluid flow as well as the gingival index decreased during the experimental period. At 4, 5, and 6 weeks after chlorhexidine application, these values in the test group appeared lower, but did not attain statistical significance.     

Diagnosis and management of peri-implant diseases

Peri-implant diseases are inflammatory lesions which may affect the peri-implant mucosa only (peri-implant mucositis) or also result in loss of supporting bone (peri-implantitis). Peri-implantitis may lead to loss of the implant. Diagnosis of peri-implant disease requires the use of conventional probing to identify the presence of bleeding on probing, and suppuration, both signs of clinical inflammation. Radiographs are required to detect loss of supporting bone. Baseline probing measurements and radiographs should be obtained once the restoration of the implant is completed to allow longitudinal monitoring of peri-implant conditions. Two cross-sectional reports from Sweden indicate that the prevalence of peri-implant disease is high. Smokers and patients who have a history of periodontitis are more at risk for peri-implant disease. The main goal of treatment of peri-implant disease is to control the infection and to prevent disease progression. A number of studies have documented the successful treatment of peri-implant mucositis combining mechanical debridement and chemical plaque control. There is evidence supporting antimicrobial treatment regimens in combination with non-surgical or surgical debridement for peri-implantitis treatment. Long-term data to support these treatment protocols is limited. Whilst it is possible to treat peri-implantitis, prevention is the goal of supportive therapy.