Quality of marginal adaptation evaluation of posterior composites in clinical trials

The evaluation of margins of restorations in clinical trials relies on the subjective assessment of evaluators, with no instrument having been developed, let alone validated, to assist in the process. The purpose of the present study was to assess the quality of evaluations of marginal adaptation by analyzing the distribution of marginal steps rated according to clinical criteria. Replicas of 435 restorations, the marginal qualities of which had been evaluated according to modified USPHS criteria, were randomly selected from the Occlusin multi-center clinical trial program. The marginal step height in the most deteriorated area of each restoration was measured by means of a digital step-height instrument. An overlap between the steps in the restorations with A (Alfa; replacement unnecessary) and B (Bravo; replacement questionable) ratings was found to be in the range of 101 microm to 321 microm. When the steps with a height greater or less than one standard deviation of the mean were excluded, the overlap was reduced to a range of 168 micro m to 173 microm. This finding indicates a marginal height boundary between A and B ratings for marginal adaptation of 170 +/- 3 microm.     

Dynamic shear properties of the temporomandibular joint disc

Shear stress might be an important factor associated with fatigue failure and damage of the temporomandibular joint disc. Little information, however, is available on the dynamic behavior of the disc in shear. Since the disc is an anisotropic and viscoelastic structure, in the present study the dependency of the dynamic shear behavior on the direction and frequency of loading was examined. Ten porcine discs were used for dynamic shear tests. Shear stress was applied in both anteroposterior (A-P test) and mediolateral (M-L test) directions. The dynamic moduli increased as the loading frequency increased. The dynamic elasticity was significantly larger in the A-P test than in the M-L test, although the dynamic viscosity was similar in both tests. The present results suggest that non-linearities, compression/shear coupling, and intrinsic viscoelasticity affect the shear material behavior of the disc, which might have important implications for the transmission of load in the temporomandibular joint.     

Incidence of penetration of a blood vessel during inferior alveolar nerve block

Aspiration of the syringe after the needle had been placed in position for an inferior alveolar nerve block (but before the anaesthetic solution was injected) in 250 patients showed that the tip of the needle was in a blood vessel in 49 (20%). Aspiration of blood was significantly more common in patients aged 9-19 years than in all others (P=0.04).     

Oral lichen planus: a preliminary clinical study on treatment with tazarotene

OBJECTIVE: The rationale for using tazarotene in oral lichen planus (OLP) is its regulatory action on the growth and differentiation of keratinocytes and on inflammation. This randomized, placebo-controlled study addresses evaluation of the effects of topic tazarotene in the treatment of OLP. DESIGN: The degree of lesions before and after treatment scored by a 6-score scale in six cases treated with tazarotene was statistically compared with those of six controls treated with placebo. SUBJECTS: Twelve patients with hyperkeratosic OLP were randomly allocated to treatment with tazarotene gel 0.1% b.i.d. or with placebo for eight consecutive weeks. METHODS: The statistical comparison was executed by means of Wilcoxon analysis for paired data. RESULTS: Patients treated with tazarotene presented a significant reduction of their lesions as compared with the control group. Among transitory side-effects, burning sensation and taste abnormalities were observed. CONCLUSION: Topical tazarotene may be a valuable therapeutic tool in the treatment of hyperkeratotic OLP.     

Validation of a Facial Image Scale to assess child dental anxiety

Summary. Objective. To examine the validity of a scale that uses faces as an indicator of children’s dental anxiety. Setting. Department of Child Dental Health waiting room, Newcastle Dental Hospital. Subjects and methods. 100 children (aged 3–18 years) completed the Facial Image Scale (FIS) and the Venham Picture Test (VPT) in the dental hospital waiting room. Results. A strong correlation (0·7) was found between the two scales, indicating good validity for the FIS. Findings also showed that a small, but significant, number of children are anxious in the dental context. Conclusion. The findings suggest that the FIS is a valid means of assessing child dental anxiety status in a clinical context.     

Biocompatibility of nickel and cobalt dental alloys

Allergies related to dentistry generally constitute delayed hypersensitivity reactions to specific dental materials. Although true allergic hypersensitivity to dental materials is rare, certain products have definite allergenic properties. This review presents a comparative evaluation of the biocompatibility of nickel-chromium, nickel-chromium-beryllium, and cobalt-chromium alloys.     

Periodontal tissue regeneration by recombinant human transforming growth factor-beta 3 in Papio ursinus

Background and Objective: Osteogenic proteins of the transforming growth factor‐β superfamily induce periodontal tissue regeneration in animal models, including primates. To our knowledge, no studies have been performed in periodontal regeneration using the transforming growth factor‐β3 isoform. In the present study, recombinant human transforming growth factor‐β3 was examined for its ability to induce periodontal tissue regeneration in the nonhuman primate, Papio ursinus. Material and Methods: Class II furcation defects were surgically created bilaterally in the maxillary and mandibular molars of four adult baboons. Heterotopic ossicles, for transplantation to selected furcation defects, were induced within the rectus abdominis muscle by recombinant human transforming growth factor‐β3. Forty days later, the periodontal defects were implanted with recombinant human transforming growth factor‐β3 in Matrigel^® as the delivery system, with recombinant human transforming growth factor‐β3 plus minced muscle tissue in Matrigel^®, or with the harvested recombinant human transforming growth factor‐β3‐induced ossicles. Sixty days after periodontal implantation, the animals were killed and the specimens harvested. Histological analysis on undecalcified sections measured the area and volume of new alveolar bone and the coronal extension of newly formed alveolar bone and cementum. Results: Morphometric analyses showed pronounced periodontal regeneration in experimental defects compared with controls. Substantial regeneration was observed in defects implanted with fragments of heterotopically induced ossicles and with recombinant human transforming growth factor‐β3 plus minced muscle tissue. Conclusion: Recombinant human transforming growth factor‐β3 in Matrigel^® significantly enhanced periodontal tissue regeneration in the nonhuman primate, P. ursinus.     

A congenital teratoma with a cleft palate: report of a case

Teratomas are benign tumors containing cells from ectodermal, mesodermal and endodermal layers. They occur in about 1 in every 4000 births and most commonly in the sacrococcygeal region, followed by the ovaries. Congenital epignathus teratomas are rare embryological neoplasms localised in the region of head and neck. An epignathus is found in approximately 1:35,000 to 1:200,000 live births. This accounts for 2-9% of all teratomas. Size and location of the neoplasm in the oronasopharynx is variable. Teratomas are partly undiagnosed at the time of birth. They may exist with an intracranial extension or as small polyps. Large epignathi can lead to difficult management during and after birth. The case of a newborn girl with a combination of an epignathus and a cleft palate is described. The epignathus presented as a huge mass extending out of the mouth of the infant girl. On the day of birth debulking of the extraoral portion of the tumor, followed by intraoral exstirpation, was performed. The results of the histologic examination indicated a congenital epignathus. Six months later a recurrence was found.