Dietary influences on the formation of dental calculus in rats

Eleven diets were evaluated for their ability to produce dental calculus in albino rats. A diet containing 50 % cornstarch, 32 % nonfat dry milk, 3 % liver powder, 5 % celluflour, 1 % cottonseed oil, 5 % powdered sucrose, 1 % calcium chloride dihydrate, 2.7 % sodium dihydrogen phosphate monohydrate, and 0.3 % magnesium sulfate (Francis and Briner 1969) was remarkably effective. On the basis of a 0–3 calculus scoring system, an average score of 2.36 (S.D. = 0.65) resulted after 4 weeks' exposure to the above diet and, after 8 weeks, the average score was 2.59 (S.D. = 0.56).
While it was found that, in general, high cornstarch and milk powder diets were associated with higher calculus scores, no other diet remotely approached the above diet in calculogenicity.     

Matrix metalloproteinase-8 (MMP-8) in pulpal and periapical inflammation and periapical root-canal exudates

AIM: To study the presence, levels and molecular forms of matrix metalloproteinase (MMP) -8 (collage-nase-2) in pulpal and periapical inflammation, and the changes in MMP-8 levels in root-canal exudates during root-canal treatment. METHODOLOGY: Periapical exudate samples were collected from 11 necrotic teeth with radiographically verified periapical periodontitis during three root-canal treatment visits with interappointment calcium hydroxide (Ca(OH)2) medication. MMP-8 levels and molecular forms were analyzed with immunofluorescent assay (IFMA) and Western immunoblot. Inflamed pulp tissue and periapical granuloma tissue (n = 10 for both) were obtained from other patients and used for MMP-8 immunohistochemical (IHC) staining. RESULTS: The periapical exudate samples demonstrated marked differences in MMP-8 levels between the teeth in the first visit and significant decrease in MMP-8 levels during the root-canal treatment (P = 0.0107). One specimen failed to show a decrease in MMP-8 below 1000 ng mL(-1) a vertical root fracture was later diagnosed and the tooth extracted. IHC staining showed that in addition to PMN-leucocytes, macrophages and plasma cells produced MMP-8 in pulp and periapical granulomas. CONCLUSIONS: The findings demonstrate the presence of MMP-8 in the inflamed pulp and periapical tissue, indicating that MMP-8 has a role in pulpal and periapical inflammation, most likely participating in tissue extracellular matrix degradation. They further indicate that MMP analysis from periapical exudate could be used to indicate and monitor inflammatory activity and the success of treatment in teeth with periapical lesions.     

Diffuse but unilateral gingival enlargement associated with von Recklinghausen neurofibromatosis: a case report

BACKGROUND: An 8-year old girl was referred for diagnosis and treatment to the Department of Periodontology Oral Surgery of the University Hospital of Liège with an unusual clinical situation: a major, non-inflammatory, diffuse but unilateral enlargement of the interproximal, marginal and attached gingiva around all teeth of the right side of both the upper maxilla and mandible, whereas the alveolar process of the left side of upper and lower arches appeared strictly normal. METHOD: The clinical examination showed delayed eruption of some permanent teeth in the 1st and 4th quadrants. Except for its asymmetric occurrence, this gingival enlargement strongly resembled phenytoin-induced enlargement or gingival fibromatosis. This unilateral expression was evocative of a vascular or neurologic pathology. Several large "café-au-lait" spots were found disseminated on the body. Several selective surgical removals of thick gingival caps impairing the eruption of some permanent teeth were performed, and the removed tissues were histologically analyzed. RESULTS: Because of the presence of the large "café-au-lait" spots, a clinical diagnosis of Von Recklinghausen's disease was given and later confirmed several times by the histological analysis of the gingival biopsies. Now, 6 years later, this gingival enlargement due to the development of intra-gingival neurofibromas is stable and all permanent teeth have had a normal eruption, but alveolar bone growth has been partly impaired by the presence of the tumor. CONCLUSIONS: The present case of unilateral diffuse hyperplasia is a unique clinical expression of neurofibromatosis type I, a slowly evolving neurodermic dysplasia.     

Immediate loading of modular transitional implants: a histologic and histomorphometric study in dogs

Modular Transitional Implants (MTI) are made from pure titanium and are used to support fixed provisional restorations during the osseointegration of definitive implants. This study histologically examined the jaw response to loaded MTIs in the dog mandible. Three implants were inserted transmucosally into each side of the mandible in 3 dogs. Stability was examined using a Periotest. Anterior and posterior implants were splinted using a cemented acrylic resin fixed partial denture to allow immediate loading. The middle implant remained unloaded and was used as a control. Dogs were sacrificed 11 to 12 weeks after implantation, and tissue blocks containing the implants were removed. Histologic examination showed that 10 of the 18 implants had good bone-to-implant contact, with the percentage of bone contacting the threaded portion of the implant varying from 30% to 65%. There was no statistical difference (p > 0.1) in percentage of bone-to-metal contact between loaded and unloaded implants. Six implants were entirely surrounded by connective tissue with or without inflammation; two implants were lost during the study. The success rate did not differ between loaded and unloaded implants. In the successful implants trabecular bone made good contact with the implant, forming supporting struts. There was bone remodeling in some bone-to-metal contact areas. It is believed that success was mainly influenced by the initial bone density at the implant site and by the uncontrolled load that the animals applied to the implants during the early healing stage.     

影响老年心血管病患者开髓治疗危险性的多因素分析

目的探讨老年心血管疾病患者开髓治疗过程中的潜在危险性及影响因素。方法对235例老年心血管疾病患者心电监护下开髓治疗的资料，按治疗时心率和血压的波动、心电图缺血性改变、心律失常的发生或加剧作为潜在的危险因素(y1～y5)及患者的年龄、性别、心血管病的种类、心功能、治疗时精神状态、麻醉效果6个自变量(x1～)x6)，应用电子计算机行多元逐步回归及logistic回归分析。结果老年心血在管疾病患者开髓治疗时潜在危险的影响因素依次为：治疗时精神紧张、麻醉效果差、心脏病种类、心功能、年龄、性别。结论通过对老年心血管疾病患者开髓治疗时潜在危险性影响因素的分析，指导临床采取有效的安全措施。     

Penetrating grease gun injury in the face

We present the case of a sailor who sustained a penetrating grease gun injury to his face, and the challenging subsequent series of events.     

Possible link between glycolysis and apoptosis induced by sodium fluoride

Fluoride has been used to prevent caries in the dentition, but the possible underlying mechanisms of cytotoxicity induction by this compound are still unclear. Since fluoride is known as an inhibitor of glycolytic enzymes, we investigated the possible connection between NaF-induced apoptosis and glycolysis in human promyelocytic leukemia HL-60 cells. NaF-induced apoptotic cell death is characterized by caspase activation, internucleosomal DNA fragmentation, loss of mitochondrial membrane potential, and production of apoptotic bodies. Higher activation of caspases-3 and -9, as compared with that of caspase-8, suggested the involvement of an extrinsic pathway. Utilization of glucose was nearly halted by NaF, whereas that of glutamine was rather enhanced. NaF enhanced the expression of Bad protein, but not that of Bcl-2 and Bax proteins, and reduced HIF-1alpha mRNA expression. Analysis of these data suggests a possible link between glycolysis and apoptosis.     

Masseter muscle thickness three years after surgical correction of class III dentofacial deformity

Objective

To analyse the effect of integrated orthodontic treatment, orthognathic surgery and orofacial myofunctional therapy on masseter muscle thickness in patients with class III dentofacial deformity three years after orthognathic surgery.

Design

A longitudinal study was conducted on 13 patients with class III dentofacial deformities, denoted here as group P1 (before surgery) and group P3 (same patients 3 years to 3 years and 8 months after surgery). Fifteen individuals with no changes in facial morphology or dental occlusion were assigned to the control group (CG). Masseter muscle ultrasonography was performed in the resting and biting situations in the three groups. Data were analysed statistically by a mixed-effects linear model considering a level of significance of P < 0.05.

Results

Significantly higher values (P < 0.01) of masseter muscle thickness (cm) were detected in group P3 (right rest: 0.82 ± 0.16, left rest: 0.87 ± 0.21, right bite: 1 ± 0.22, left bite: 1.04 ± 0.28) compared to group P1 (right rest: 0.63 ± 0.19, left rest: 0.64 ± 0.15, right bite: 0.87 ± 0.16, left bite: 0.88 ± 0.14). Between P3 and CG (right rest: 1.02 ± 0.19, left rest: 1 ± 0.19, right bite: 1.18 ± 0.22, left bite: 1.16 ± 0.22) there was a significant difference on the right side of the muscle (P < 0.05) in both situations and on the left side at rest.

Conclusion

The proposed treatment resulted in improved masseter muscle thickness in patients with class III dentofacial deformity.