Periodontic-endodontic combined lesions affect the quality of life of patients. The present study aimed to explore a way to achieve maximal effect in treating periodontic-endodontic combined lesions by using a combination of minocycline hydrochloride ointment (MHO) and mineral trioxide aggregate (MTA). In the present study, 294 patients were randomly divided into four groups: Control group, MHO group, MTA group and combination group. Endodontic and periodontic therapy was applied simultaneously on the anterior and posterior teeth of patients, and patient characteristics, gingival index (GI) and probing depth (PD) were noted when the patients were treated with the different strategies. Reexamination was performed 4 weeks after treatment and follow-up was performed 2 years later. The present study demonstrated that medical history, root filling and periapical condition within the patients were deemed as key factors in determining the success of treatment of periodontic-endodontic combined lesions. The effect of the combination treatment significantly exceeded that of either treatment alone (P<0.05). In addition, the teeth were significantly improved for patients with pathological types I, II and III in the combination group compared with either treatment group alone (P<0.05). Furthermore, compared with the MTA and MHO groups alone, the combination group demonstrated a significant decrease in PD and GI in severe periodontic-endodontic combined lesions. In conclusion, the present findings implied that combination treatment is significantly superior to single treatments applied to patients with severe periodontic-endodontic combined lesions.

OBJECTIVE: This work aims to observe the healing of periimplant mucosal tissue injury in beagle dogs after subgingival retraction cord placement by examining the gingival index (GI), quantity of gingival crevicular fluid (GCF), and the proinflammatory cytokine in the GCF.
METHODS: In eight beagle dogs, the fourth mandibular premolars on the left side were extracted (n=8); after two months of healing, bone-level implants were installed. A plaque control regimen was performed throughout the duration of the experiment. After three months, retraction cords were placed subgingivally for 5 min before the cement-retained implant-supported crowns were cemented. GI, GCF quantity, and levels of tumor necrosis factor-alpha (TNF-α) in GCF were assessed before application and on days 1, 3, 7, 14, 28, and 56 after application.
RESULTS: GI, quantity of GCF, and TNF-α were significantly increased on days 1, 3, and 7 compared with those at the baseline and on days 14, 28, and 56 (P<0.05), and no statistically significant differences were observed among those on days 14, 28, and 56 and the baseline (P>0.05).
CONCLUSIONS: Under the circumstances of good oral hygiene, acute injury caused by placing retraction cord subgingivally in periimplant mucosal tissue of bone-level implant is reversible. GI, the quantity of GCF, and TNF-α on day 14 return to the baseline levels.
目的 通过观察比格犬种植义齿排龈后牙龈指数、龈沟液量和龈沟液中炎症细胞因子肿瘤坏死因子-α（TNF-
α）等指标的变化，探讨排龈所致种植义齿周围软组织损伤愈后情况。方法 拔除8只比格犬左侧下颌第四前磨牙（n=8），严格控制口腔菌斑，2个月后行骨水平种植体植入，3个月后行全冠粘接固位。全冠粘接前使用排龈线排龈5 min，排龈前和排龈后1、3、7、14、28、56 d，分别记录种植体的牙龈指数，测量龈沟液量并用酶联免疫吸附试验检测龈沟液中TNF-α的变化。结果 种植体牙龈指数、龈沟液量、TNF-α在排龈后第1、3、7天均大于排龈前和排龈后第14、28、56天（P<0.05），第14、28、56天恢复至排龈前水平，差异无统计学意义（P>0.05）。结论 保持良好口腔卫生的情况下，骨水平种植义齿周围软组织排龈线造成的排龈损伤是可逆性损伤，牙龈指数、龈沟液量、TNF-α在第14天恢复至排龈前水平。.

OBJECTIVE: To investigate the effects of an egg yolk-derived immunoglobulin (IgY) specific to Prevotella intermedia in vitro and in vivo.
RESULTS: An IgY specific to P. intermedia was produced by immunizing hens with formaldehyde-inactivated P. intermedia and showed high titres when subjected to an ELISA. The obtained IgY inhibited the growth of P. intermedia in a dose-dependent manner at concentrations from 1 to 20 mg ml(-1) in Center for Disease Control and Prevention liquid medium. Forty rats were challenged with P. intermedia on gingivae and then randomly divided into four groups, which were syringed respectively with phosphate-buffered saline, 1 mg ml(-1) of tinidazole, 20 mg ml(-1) of nonspecific IgY and 20 mg ml(-1) of the IgY specific to P. intermedia at a dosage of 300 μl per day. Gingival index (GI), plaque index (PI), bleeding on probing (BOP), counts of white blood cell (WBC) and histopathological slide of the gums were measured after treatment for 15 days. The gingivitis rats treated with the IgY specific to P. intermedia showed significantly decreased GI, PI, BOP and WBC (P < 0·05). Gum histopathology of the treated rats demonstrated a superior protective effect of the specific IgY on P. intermedia-mediated gingivitis.
CONCLUSIONS: A new immunoglobulin specific to P. intermedia was developed from egg yolk. This specific IgY can dose-dependently inhibit the growth of P. intermedia and protect rats from gingivitis induced by P. intermedia.
CONCLUSIONS: The new IgY has potential for the treatment of P. intermedia-mediated gingivitis.