Inhibition of the proliferation of human periodontal ligament fibroblasts by hyaluronidase

Hyaluronan (HA) exists in various living tissues as one of the major matrix macromolecules, and is well known to play an integral role in cell differentiation and proliferation. The present study was conducted to elucidate whether or not the proliferation of periodontal ligament (PDL) cells are affected specifically by the degradation of HA by hyaluronidasze (HAase). Human PDL fibroblasts were isolated and cultured with and without 15-150U/ml bovine testicular HAase from 1 to 11 days after seeding. The cells were also cultured with anti-CD44 antibody of 2 microg/ml. For the control against the anti-CD44 antibody treatment, 2 microg/ml IgG was used. The HA-dependent pericellular matrix was visualized by particle-exclusion assay. The number of cells was counted by MTT assay during the proliferation. The mRNA levels of HA synthases (HASs), HAases (HYALs) and CD44s were examined by a quantitative real-time PCR analysis. The cell proliferation was inhibited by the treatment with HAase and anti-CD44 antibody in cultured PDL fibroblasts. HASs mRNAs were down-regulated, whereas HYALs mRNAs were up-regulated significantly by the treatment with HAase and anti-CD44 antibody. The CD44s mRNA level exhibited no significant changes. These results suggest that HA may contribute to modulate the proliferation of cultured human PDL cells through a CD44-mediated mechanism.     

Persistent endodontic lesion due to complex cementodentinal tears in a maxillary central incisor--a case report

The cementodentinal tear is rarely detected by noninvasive procedures owing to its clinical picture simulating a root fracture or a periodontal or endodontic lesion. We present a case of complex cementodentinal tears in a 79-year-old woman who presented a repeated swelling at the labial mucosa of the left maxillary central incisor for 6 months. Periapical radiographs demonstrated a vertical radiolucent fracture line extending from the root apex along the mesial aspect of the root to near the middle portion of the root of the left maxillary central incisor. Because endodontic re-treatment failed to cure the disease, periapical surgery was performed, and 2 fractured U-shaped root fragments around the apical root surface were removed. Histologic examination showed that the 2 fractured root fragments were composed mainly of the dentin covered by a thin layer of the cementum and overlying periodontal ligament tissue, suggesting cementodentinal tears. A swelling recurred 8 months after the initial operation. Therefore, a second periapical surgery was performed. Although no obvious fracture line was observed around the root surface, the second surgery did not cure the disease, either. A persistent small swelling was noted at the alveolar mucosa of the affected tooth during the follow-up. We conclude that although a cementodentinal tear can be detected by a careful radiographic examination, its clinical outcome is not predictable by surgical removal only.     

CSF-1对体外培养人牙囊细胞OPG表达的影响

目的研究集落刺激因子(CSF-1)对体外培养的人牙囊细胞骨保护素(OPG)表达的影响。方法原代培养人牙囊细胞,传代至第3代,制备细胞爬片,进行OPG免疫组化染色;3~6代人牙囊细胞长至80%时,用胰酶消化,离心,重悬,制成单细胞悬液,接种到细胞培养皿,细胞长满至80%时,培养基中加入25ng/ml的CSF-1,孵育0.5、1、3、6h,分别收集上清液,ELISA法检测OPG蛋白分泌量的变化,提取总RNA进行RT-PCR,检测OPG mRNA的表达变化。结果正常人牙囊细胞OPG蛋白表达阳性;25ng/ml的CSF-1可降低人牙囊细胞OPG的表达,共同孵育1h,OPG表达降至最低(P<0.05)。结论牙囊细胞表达OPG,同时在牙齿萌出的特定时期,CSF-1通过下调人牙囊细胞OPG,减弱对破骨细胞形成的抑制作用,促进破骨细胞分化成熟,调节牙齿萌出。     

p53基因抑制涎腺腺样囊性癌细胞端粒酶及增殖活性

目的研究外源性野生型p53基因对涎腺腺样囊性癌细胞的抑制作用。方法构建携带野生型p53基因的腺病毒表达载体，以脂质体法转染涎腺腺样囊性癌SACC-83细胞，RT-PCR检测p53基因表达；采用TRAP—PCR—ELISA法检测转染细胞端粒酶活性，荧光素酶分析法检测人端粒酶逆转录酶基因（hTERT）肩动子的转录；流式细胞术、软琼脂集落实验及裸鼠成瘤实验观察细胞生物特性的变化。结果外源性野生型p53基因导入使p53基因在涎腺腺样囊性癌细胞SACC-83中表达增强，其端粒酶活性降低、hTERT启动子转录抑制；转染细胞出现G1期阻滞，软琼脂集落形成率减少，裸鼠成瘤能力降低。结论腺病毒载体介导的外源性野生型p53基因可以抑制涎腺腺样囊性癌细胞端粒酶活性及细胞恶性表型。     

Analysis of postoperative symptoms following surgical endodontic treatment.

OBJECTIVE: The purpose of this prospective study was to analyze postoperative pain and swelling of patients undergoing surgical endodontic treatment using a strict protocol incorporating measures to control postoperative symptoms. METHOD AND MATERIALS: The study consisted of 82 patients referred for surgical endodontic treatment. All surgical procedures were performed using a microsurgical technique employing strict protocol. All patients were premedicated with a single dose of oral dexamethasone (8 mg) preoperatively and two single doses (4 mg) 1 and 2 days postoperatively. Antibiotics were prescribed selectively only when severe symptoms were present due to infection. Patients were administered chlorhexidine mouthwash twice daily starting 3 days before the operation and an additional 7 days postoperatively starting the day after surgery. Cold compresses were applied on the skin at the site of surgery intermittently every 15 minutes during the operative day. Pain and swelling were recorded pre- and postoperatively, and the influence of different variables on postoperative sequelae were analyzed. RESULTS: One day postoperatively, 76.4% of the patients were completely pain free, less than 4% had moderate pain, and 64.7% did not report any swelling. The preoperative symptoms significantly influenced the pain experience post-surgery. CONCLUSION: There was a low incidence of postoperative pain and swelling following endodontic surgical treatment according to protocol with measures to control postoperative signs and symptoms. Patients with preoperative pain were more likely to have postoperative pain.     

Advocacy training in US advanced pediatric dentistry training programs

PURPOSE: This study: (1) assessed pediatric dentistry residency program directors' attitudes toward and involvement in advocacy training; and (2) identified types and extent of advocacy training in U.S. pediatric dentistry programs. METHODS: Between October 2005 and February 2006, all 66 pediatric dentistry residency program directors were invited to complete a 62-item online questionnaire. The survey investigated: (1) directors' attitudes toward advocacy training; (2) nature of advocacy training offered during residency; (3) extent of resident involvement in different settings; and (4) directors' involvement in advocacy. RESULTS: Forty-two program directors responded (64%). Overall, respondents agreed that advocacy by pediatric dentists for children beyond the dental office was important and that residency programs should provide advocacy training. Most programs did not routinely offer advocacy opportunities in nonclinical settings. Over half of programs required community outreach clinic rotations for all residents. One third offered didactic curriculum in the legislative process. Over 50% of program directors reported personal involvement in legislative oral health lobbying within 3 years, but fewer than a third were involved with professional political action committees (PACs). CONCLUSIONS: Advocacy is seen as on important in pediatric dentistry but variation in attitudes of program directors and program offerings exists in US training programs.     

Management of interdental papillae loss with forced eruption, immediate implantation, and root-form pontic

BACKGROUND: A 25-year-old Asian woman complained of an unesthetic black triangle between her upper right front teeth. Defective interdental papillae may result from external root resorption, which makes esthetic restoration more difficult. A combined use of forced eruption, immediate implant placement, and a root-form pontic made a successful esthetic and functional restoration. METHODS: The treatment sequences of this patient included short-term forced eruption, subsequent immediate implant placement after tooth extraction, and a provisional root-form pontic restoration. A final prosthesis was completed 6 months later, followed by clinical maintenance. RESULTS: Papillae were augmented by forced eruption. After immediate implantation and root-form pontic placement had been performed, the peri-implant soft and hard tissues were manipulated and maintained in a stable state. CONCLUSIONS: We successfully reconstructed the interdental papillae and replaced the deficient tooth with an immediate implantation. During 2 years of follow-up, the implant and peri-implant structures remained stable and healthy.     

A newly designed resonance frequency analysis device for dental implant stability detection

Resonance frequency (RF) analysis technology was used to design a new dental implant stability detector. To calibrate and test the performance of this novel apparatus, in vitro and in vivo models, respectively, were used. The RF values of the test implants detected using our new device and a commercially available analogous device (Osstell) were compared. Further, implant stability status was also detected clinically using our device at 2, 4, 8, and 12 weeks after surgery. A high correlation was demonstrated between the values measured with the two devices (y = 0.31x-12.45; R2 = 0.98, p < 0.05). In our clinical tests, an initial RF value above 10.0 kHz indicated that the implant was ready to accept functional loading, while values in the 4.0-10.0 kHz range reflected the need for further osseointegration. In conclusion, these results indicated that our new device might be useful in a clinical setting for evaluating the healing status of a placed implant.     

Oral health care system in Chinese Mainland

The purpose of this review is to describe the training of dental professionals and to give an overview of the oral health care system in Mainland China. It may be of interest and importance for American readers to become aware that there are alternative practice structures and the world is getting smaller.     

Transient loss of power of accommodation in 1 eye following inferior alveolar nerve block: report of 2 cases

Unintended intravascular injection from inferior alveolar nerve blocks can result in frustrating distant complications affecting such structures as the middle ear and eyes. Possible complications affecting the eyes include blurring of vision, diplopia, mydriasis, palpebral ptosis and amaurosis (temporary or permanent). In this article, we present a complication that has been reported only rarely. Two patients developed transient loss of power of accommodation of the eye resulting in blurred vision after routine inferior alveolar nerve blocks on the ipsilateral side. Clear vision returned within 10-15 minutes after completion of the blocks. The possible explanation for this phenomenon is accidental injection into the neurovascular bundle of local anesthetic agents, which were carried via the blood to the orbital region. This resulted in paralysis of a branch of cranial nerve III, the short ciliary nerves that innervate the ciliary muscle, which controls accommodation.