Characterization of verruciform xanthoma by in situ hybridization and immunohistochemistry

Verruciform xanthoma (VX) is a rare, benign lesion, mainly found in the oral mucosa. Histologically and ultrastructurally. the lesion is characteristic and well defined. However, the etiology of the lesion remains unclear. The purpose of the present study was to elaborate upon the pathogenesis of VX by evaluation of an additional series of oral examples for human papillomaviruses (HPV). using immunohistochemistry and in situ hybridization, and to further characterize the cellular components of VX immunohistochemically. Twelve specimens diagnosed as VX were retrospectively collected. One of the twelve specimens was positive for HPV types 6/11 by in situ hybridization. None of the twelve specimens demonstrated the presence of HPV antigen by immunohistochemistry. By immunohis-tochemical studies, the predominant cells in the inflammatory infiltrate were T cells. The foam cells were of monocyte/macrophage lineage. S-100-positive (Langerhans) cells were occasionally found in the suprabasal layer of the epithelium. HLA-DR-positive keratinocytes were noted at the intense inflammatory sites. Taken together, these findings suggest that an immune response may play a role, at leas! in part, in VX pathogenesis.     

A case for absolute anchorage

It would be an understatement to say that implant technology has changed the face of dentistry in the past 10 years or so. Both the surgical and restorative specialties have undergone dramatic transformation from treatment planning through all phases of rehabilitation. However, the same cannot necessarily be said for the specialty of orthodontics. Although it could be argued that implants have had an impact on the planning and setup of orthodontic cases (such as in congenitally missing teeth situations), the actual utilization of implants as an integral part of mechanotherapy has only begun to be realized. The ultimate extension of this application of using implants to enhance tooth movement would be to employ implants that are designed solely for the purpose of facilitating orthodontic therapy, with no intention to restore, but rather to explant such implants, after their purpose is fulfilled.     

Sonographic evaluation of the ranges of condylar translation and of temporomandibular joint space as well as first comparison with symptomatic joints

AIM: To assess the normal ranges of condylar translation and width of the lateral temporomandibular joint (TMJ) of a healthy population by sonography and permit comparison of findings made in individual patients using this norm. PATIENTS AND METHOD: Fifty non-orthodontically treated, asymptomatic volunteers (100 joints) were subdivided by Angle classes (I = 20, II = 15, III = 15) and evaluated. Reliability was assessed in 15 of those volunteers. The validity was checked in 8 more patients with temporomandibular dysfunction (TMD), all class II with disc dislocation diagnosed by means of MRI. Sonographic assessment of condylar translation from centric occlusion to maximum opening and during protrusion and mediotrusion was performed with a probe positioned parallel to the zygomatic arch. RESULTS: Translation during opening was 12.7+/-3.2 mm in class I, 12.9+/-3.3 mm in class II and 10.9+/-3.6 mm in class III. Protrusive translation was 7.4+/-2.5 mm/10.3+/-4.4 mm/6.8+/-2.1mm, respectively; and mediotrusive translation was 7.9+/-2.6 mm/10.8+/-3.4 mm/6.7+/-2.4 mm, respectively. Class II had longer and class III shorter condylar translations. The lateral joint space in occlusion and protrusion was wider in class II than in classes I and III. Symptomatic patients had shorter condylar translations than asymptomatic volunteers. CONCLUSION: Patients with class II had a more anteroposterior mobility, class III shorter translation. Significant sonographic differences of condylar translation from the norm did not correspond with clinical findings. This demonstrates the higher sensitivity of sonography for the evaluation of individual condylar translation. It is a sensitive tool for assessing joint function.     

Flare-ups in endodontics and their relationship to various medicaments

The purpose of this research is to investigate the frequency of endodontic flare-ups using a visual analogue scale. Definitions of flare-ups vary widely as does their reported frequency. A flare-up was defined as an increase of 20 or more points on the visual analogue scale for a given tooth, within the periods of 4 h and 24 h after the initial treatment appointment. The data from a previous study were used to determine the incidence of flare-ups after using three modalities (Ledermix, calcium hydroxide and no medication) to manage patients presenting for relief of pain of endodontic origin. A statistical analysis showed that there were no significant differences in flare-up rates at both the 4-h and 24-h periods between the three modalities. Further research is required using the above definition of a flare-up and standardising treatment protocols.     

Beta-glucuronidase activity in saliva: relationship to clinical periodontal parameters

BACKGROUND: Beta-glucuronidase (betaG) in gingival crevicular fluid (GCF), a marker of neutrophil influx into the crevicular environment, has previously been shown to be correlated with periodontal clinical parameters at individual sites (probing depth and clinical attachment level). Furthermore, elevated levels of betaG were found to be a risk factor for periodontal attachment loss. Analysis of betaG in saliva may be a measure of crevicular neutrophil influx for the whole mouth. The purpose of this cross-sectional study was to evaluate the relationship between betaG activity in saliva and periodontal clinical parameters in subjects demonstrating various levels of periodontal disease. METHODS: The study population consisted of 380 subjects (108 males and 272 females). A sample of unstimulated whole saliva and a venous blood sample were obtained from each subject, and a periodontal examination, which included measurement of probing depth (PD), attachment level (AL), and gingival index (GI) was performed. The unmodified saliva samples were frozen at -20 degrees C and analyzed for betaG activity. The blood samples were analyzed for number of white blood cells, neutrophils, monocytes, lymphocytes, and platelets. Statistical analysis was conducted to determine the association between salivary betaG activity and the whole-mouth clinical periodontal parameters, complete blood count, smoking status, and age. RESULTS: Highly significant correlations between salivary betaG activity and mean probing depth (MPD), mean gingival index (MGI), and the number of sites with probing depth > or = 5 mm were found. When subjects were divided into tertiles based on their MPD and MGI, elevated salivary betaG activity was detected in subjects in the 2 upper tertiles. Logistic regression modeling was used to determine which of the clinical or laboratory parameters were able to identify patients with at least 4 sites with PD > or = 5 mm. Salivary betaG activity > or = 100 produced an odds ratio (OR) of 3.77. In comparison, current and former smokers had an OR of 3.15 and 2.29, respectively. CONLCUSIONS: The results suggest that a significant association exists between periodontal clinical parameters and salivary betaG activity. Due to the non-invasive and simple nature of saliva collection, this association should be studied to determine its usefulness as a screening test for periodontitis, and a means of monitoring the response to treatment.     

Comparison of clinical outcomes using a nickel titanium rotary or stainless steel hand file instrumentation technique

The purpose of this study was to evaluate the concept that novice clinicians could perform clinical endodontics better and more efficiently if the stainless steel hand file technique is replaced with a nickel titanium rotary file technique. In phase 1 of the study, every endodontic case performed by 2 groups was evaluated for total treatment time. In phase 2, the mesial roots of mandibular molars were evaluated for radiographic quality of completed obturation. The authors found that when the rotary file technique was substituted for the hand file technique, appointment time for case completion was significantly decreased (P<.001) and overall radiographic quality of mandibular molar mesial root obturation was significantly increased (P=.0009). These results support the hypothesis that novice clinicians can perform endodontic therapy more efficiently when using a nickel titanium rotary file technique. In addition, no differences were noted in the incidence of file fracture when using rotary instruments.     

An evaluation of a technique to remove stains from teeth using microabrasion

BACKGROUND: Microabrasion using a paste made of acid and pumice is a technique that has been used to remove white, yellow and brown stains from enamel. The authors evaluated the technique by studying the effectiveness of a proprietary microabrasion product. METHODS: One author used microabrasion to remove white, yellow and brown stains from within the outermost layer of the tooth enamel of 32 subjects. Standardized slides of the teeth were taken before and one week after treatment. Four prosthodontists evaluated the paired images, using a standardized questionnaire and visual analog scales ranging from 1 (no improvement in appearance or stain not removed at all) to 7 (exceptional improvement in appearance or stain totally removed). The evaluators were calibrated and blinded. RESULTS: The evaluators always identified a difference between the pretreatment slides and posttreatment slides; they found no difference between the control slides. In all cases but one (97 percent), the treated teeth had improved in appearance with more uniformity in color. Analysis of variance revealed no differences between evaluator ratings (P = .146). The intraclass correlation coefficient for ratings of individual cases by different evaluators was 0.72, representing a "good" level of correlation of the ratings for improvement of appearance and for stain removal. Mean (+/- standard deviation) ratings were 5.38 (+/- 1.26) for improvement of appearance and 5.06 (+/- 1.26) for stain removal. CONCLUSIONS: This study showed that enamel microabrasion could remove stains from within the outermost layer of tooth enamel, thereby improving the appearance of the teeth. CLINICAL IMPLICATIONS: This study supports recommendations that enamel microabrasion is an effective, atraumatic method of improving the appearance of teeth with stains in the outermost layer of enamel.     

Effect of implant surface roughness and loading on peri-implant bone formation

BACKGROUND: Critical factors for the establishment of osseointegration are the implant surface microtopography and the local mechanical environment. The present study evaluated the bone response around a turned (T) and a roughened (R) implant for either an unloaded or a well-controlled loaded situation. METHODS: Bone chambers were installed in the tibia of 20 rabbits. In each of the chambers, two identical displacement-controlled loading experiments were performed: 30 microm for 400 cycles at 1 Hz, three times a week for 9 weeks versus 0-microm implant displacement. A linear mixed model and a logistic mixed model with alpha = 5% were set to study the significant effect of the surface texture on the peri-implant bone response in the unloaded (T-0 microm versus R-0 microm) and the loaded (T-30 microm versus R-30 microm) mode. RESULTS: Results indicated no microtopographic dependence of the bone response further away from the implant in unloaded and loaded conditions. For a load-free implant, osseointegration seemed to occur with a higher incidence at a roughened compared to a turned implant surface. In the presence of loading, the topographic dependency of the osteogenic activity at the interface was overruled by the loading-related bone response, revealing no significant differences in osseointegration incidence between T and R. CONCLUSION: A predominant effect of the interfacial mechanical environment over the implant surface characteristics on the differentiating cell population is suggested.     

In-use peroxide kinetics of 10% hydrogen peroxide whitening strips

OBJECTIVE: Clinical research was conducted to establish the peroxide degradation profile of a very thin 10% hydrogen peroxide bleaching gel delivered on a flexible polyethylene strip. METHODS: Sixteen subjects participated in this study of Crest Whitestrips Premium, a thin layer of 10% hydrogen peroxide gel. Application was supervised, and strips were removed after five, 10, 30, and 60 minutes. Samples were collected from the strips, teeth, gingiva, and saliva, and peroxide levels were derived using a colorimetric peroxide assay. RESULTS: At five minutes, median peroxide concentrations were 7.3%, 6.4%, and 0.7% for strips, teeth, and gingiva, respectively, declining to 4.6%, 2.9%, and 0.1% at 30 minutes. Salivary samples never exceeded a median concentration of 0.014% at any time point. Samples differed significantly (p < 0.01) with respect to the 30- and 60-minute area-under-the-curve calculations, with the highest concentrations on the strip and teeth, and the lowest on the gingiva and in saliva. Median peroxide concentrations on strips and teeth remained above 2% over 60 minutes. At all post-treatment time points, the gingival peroxide concentration was an order of magnitude lower than the teeth samples. CONCLUSION: Use of 10% hydrogen peroxide whitening strips yielded appreciable peroxide on teeth over a 60-minute period, with rapid peroxide degradation on the gingiva, and exceedingly low accumulation in saliva anytime during use.     

Effect of loading mode on bond strength of orthodontic brackets bonded with 2 systems.

INTRODUCTION: A new orthodontic bracket bonding method or material invariably spawns bond strength studies examining the efficacy of the innovation. The primary purpose of this project was to ascertain whether the mode of in-vitro bracket debonding used in a study affects the measured bond strength. The secondary aim was to compare the bond strengths of 2 different bonding systems. METHODS: Flattened stainless steel orthodontic brackets were bonded to flattened bovine enamel with a resin composite bonding agent (Transbond XT, 3M Unitek, Monrovia, Calif). The enamel was prepared with traditional acid etching and priming (37% phosphoric acid gel and Transbond XT Primer, 3M Unitek) or a single-step method (Transbond Plus, 3M Unitek) that combined etching and priming. Cement thickness was kept constant, and bonding was done under controlled temperature and humidity. Brackets were debonded in shear-peel, tension, or torsion. RESULTS: When tested in shear-peel mode, traditional etching and priming produced a stronger bond than the single-step self-etch system. When tested in tension, the traditional bond was weaker than the single-step bond, and when tested in torsion, the bond strengths were similar. CONCLUSIONS: Bond strength can vary depending on the method of testing. Claims of clinical efficacy might not be valid.