Immunohistochemical localization of oncostatin M in epithelialized apical periodontitis lesions

Aim  To investigate the in situ location of oncostatin M (OSM) in epithelialized apical periodontitis lesions.
Methodology  Thirty periapical lesions of pulpal origin were collected with informed consent from patients at the time of apical surgery. Tissue specimens were fixed with 10% buffered formalin overnight, dehydrated in an ascending series of graded alcohol, and embedded in paraffin. Five micron sections from formalin-fixed, paraffin-embedded specimens were examined by immunohistochemistry. In addition, another section from each specimen was stained with haematoxylin and eosin to assess the presence of inflammatory infiltrates. Differences in OSM expression between tissue with low and high levels of inflammation were subsequently analyzed by Fisher's exact test.
Results  Based on histological examination of haematoxylin and eosin stained sections, all specimens revealed the morphology of epithelialized apical periodontitis lesions. The results from immunohistochemistry demonstrated that OSM stain was detected in the inflammatory infiltrates, epithelium, connective tissue, and endothelium. The OSM signal was mainly expressed in endothelial cells (100%) followed by inflammatory cells (93.33%), epithelial cells (53.33%), and fibroblasts (16.67%). In addition, OSM expression was significantly higher in epithelialized apical periodontitis with higher levels of inflammatory infiltrates ( P  < 0.001).
Conclusions  Oncostatin M was found to be expressed in epithelialized apical periodontitis lesions and would form part of the cytokine network involved in the disease process of apical periodontitis.     

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.     

Histologic examination of pedicled buccal fat pad graft in oral submucous fibrosis.

PURPOSE: This report evaluates the wound healing process of buccal fat pad (BFP) grafted on a defect of the buccal mucosa for oral submucous fibrosis (OSF). PATIENTS AND METHODS: Sixteen patients with limitation of mouth opening under the diagnosis of OSF were surgically treated by cutting the fibrotic bands on the buccal mucosa (10 bilateral and 6 unilateral). The defects created were then covered by a BFP graft. The bulging BFP was trimmed postoperatively on a weekly basis until it was fully epithelialized. The specimens were stained and examined microscopically. RESULTS: Inflammatory cell infiltrate, blood vessel congestion, and fibrinous exudates covering the BFP were obvious by week 2. At week 3, blood vessel congestion and fat cell number decreased markedly. Evidence of stratified squamous epithelium with parakeratosis was seen in the margin of the BFP graft. At week 4, the number of fat cells decreased significantly and the original BFP was almost completely replaced by granulation tissue. The original BFP was fully covered by stratified squamous epithelium by week 5. CONCLUSIONS: The BFP graft has been widely used for covering exposed defects created by fibrotic band excision for the improvement of mouth opening limitation. The healing process was documented microscopically by weekly observation.     

Infection with a gram-negative organism stimulates gingival collagenase production in nondiabetic and diabetic germfree rats

Experimental diabetes in the rat rapidly produces a shift in the gingival crevicular microflora which is followed, within weeks, by increased production of collagenase by the gingival tissues. To assess the contribution of endogenous (hormonal or metabolic) and exogenous (altered crevicular microflora) factors on this diabetes-induced abnormality in collagenase production, the following series of experiments was undertaken: In each experiment, the germfree rats were housed in two isolators. Half of the animals in both isolators were rendered diabetic (D) with streptozotocin while the remainder were left untreated (non-diabetic (ND) controls). All of the germfree ND and D rats in one isolator of the pair were then infected with either a Gram-positive (S. mitis or A. odontolyticus) or a Gram-negative (Capnocytophaga, A. aclmomycetemcomitans or B. gingivalis) organism. In the other isolator, the ND and D rats were maintained in their germfree state. After 3 wk, the germfree and monoinfected rats were killed and the gingiva (and in one experiment, skin) were dissected. Collagenase activity produced by gingiva in culture (or extracted from gingiva or from skin) was measured using ¹⁴C-collagen fibrils (or [³Hmethyl] collagen molecules) as the substrate. Diabetes increased the collagenolytic activity in the gingiva and skin of the germfree rats. Infecting the germfree rats with a Gram-positive organism had no effect on collagenase activity generated by the gingival explants in the tissue culture system. In contrast, infection with any of the Gram-negative organisms dramatically increased the collagenase activity in the gingival tissues of the ND rats in culture, an effect not seen in the D group of rats using this system. However, monoinfection with B. gingivalis did increase collagenase activity in the extracts of gingiva (but not in skin) from both ND and D rats, with the latter group showing the highest level of enzyme activity. We suggest (i) that experimental diabetes stimulates collagenase production in gingiva by both endogenous (hormonal) and exogenous (bacterial) mechanisms, and (ii) that crevicular Gram-negative organisms stimulate collagenolysis in the adjacent gingival tissues by releasing bacterial products (e.g. endotoxins) which penetrate into the connective tissue and enhance host cell collagenase production.     

库存软骨异体移植的动物实验研究──组织学、组织化学、电镜观察

为寻找理想的软骨库存液，本实验采用异体猪肋软骨皮下移植模型，研究了经０．４％戊二醛、甲醛混合液保存４周的软骨移植物在异体移植１、３、５月后的组织、组化及电镜观的变化。结果表明该保存液处理的软骨组织的细胞结构、酶化学生成物于移植５月后与正常组织相比变化不大。提示软骨细胞仍具有一定活力及增殖潜力。本实验认为０．４％戊二醛、甲醛混合液是一种优良的软骨库存液。     

Comparison of stability between cylindrical and conical type mini-implants. Mechanical and histological properties

OBJECTIVE: To investigate the mechanical and histologic properties of conical compared with cylindrical shaped mini-implants in terms of the success rate. MATERIALS AND METHODS: The samples consisted of cylindrical and conical groups, and commonly had 1.6 mm diameter and 6.0 mm length (Jeil Medical Corporation, Seoul, Korea) placed in beagle dogs. The mechanical study for analyzing maximum insertion torque (MIT), maximum removal torque (MRT), and torque ratio (TR; MRT/MIT) in Sawbones (Pacific Research Laboratories Inc, Vashon, Wash), and the animal study for resonance frequency analysis (RFA) and histomorphometric analysis (bone-to-implant contact and bone area) in two beagle dogs were done. All measurements were statistically evaluated using independent t-tests to determine any difference in MIT, MRT, TR, RFA, bone-to-implant contact (BIC), and bone area (BA) between the cylindrical group and conical group. A P value less than 0.05 was considered significant. RESULTS: The conical group showed significantly higher MIT and MRT than the cylindrical group in the mechanical study. However, there was no significant difference in RFA, BIC, and BA between the two groups in the animal and histomorphometric studies. CONCLUSIONS: Although the conical shaped mini-implant could induce tight contact to the adjacent bone tissue and might produce good primary stability, the conical shape may need modification of the thread structure and insertion technique to reduce the excessive insertion torque while maintaining the high resistance to removal.     

局部应用二磷酸盐对鼠正畸牙移动影响的研究

目的 探讨局部注射Zoledronate溶液对鼠正畸牙齿移动距离与牙周组织形态的影响。方法 选用42只雄性Wistar大鼠，牵引其上颌第一磨牙近中移动。实验中分别将Zoledronate溶液及生理盐水注射入实验组（左侧）及对照组大鼠（双侧）上颌第一磨牙腭侧的粘骨膜下。注射于实验前3d开始，共进行9次，每3d一次。分别在加力0、3、7、14、21d后记录上颌第一磨牙移动距离，组织HE染色后，观察牙周组织形态学的改变。结果 ①实验组大鼠牙齿移动距离明显低于对照组。②实验组大鼠压力侧破骨细胞数在实验全过程中均低于对照组，而根分叉区破牙骨质细胞数除加力14d外，2组差异无显著性。③实验过程中Zoledronate溶液对破骨细胞和破牙骨质细胞以外的细胞作用不明显。结论 Zoledronate能有效地抑制支抗牙移动，减少压力侧牙槽骨表面破骨细胞数。     

Esthetic outcome of implant-supported single-tooth replacements assessed by the patient and by prosthodontists

PURPOSE: The objective of this study was to assess and compare patients' and clinicians' judgments of the esthetic outcome of implant-supported single-tooth replacements. MATERIALS AND METHODS: In all, 29 patients with 41 single implant-supported crowns in the maxillary anterior region participated in the study. The esthetic outcome of the implant-supported crowns was assessed by the patients and by 5 prosthodontists by means of a questionnaire in which various esthetics-related variables were addressed and responded to using visual analogue scales. Multiple regression analyses were used to evaluate the influence of the variables on the "overall satisfaction" with the implant-supported crown. RESULTS: Most variables in the patients' assessments revealed mean values above 90% and median values close to 100%. No single factor used in the multiple regression analysis was found to influence a patient's satisfaction with appearance of the crown at a statistically significant level. The clinicians' degree of satisfaction was for all variables lower than that of the patients. In 89% of the cases the clinicians could correctly locate the single implant-supported crown. Among the variables assessed, surrounding soft tissue appearance and form of the crown had the strongest influence on the clinician's overall satisfaction with the appearance of the crown. CONCLUSION: Appreciation of the esthetic outcome of the single implant-supported crowns was rated higher by the patients than by the prosthodontists. Furthermore, factors considered by professionals to be of significance for the esthetic result of the restorative treatment may not be of decisive importance for the patient's satisfaction.