Effect of Er:YAG laser irradiations on shear bond strength of three self-adhesive resin cements to dentin.

OBJECTIVE: The purpose of this study was to evaluate the influence of Er:YAG laser irradiation on shear-bond strength of self-adhesive resin cements to dentin. BACKGROUND DATA: Different laser-irradiation settings are used for dentin-surface pretreatment, which may affect the bond strength of resins. METHODS: Fourty-five extracted third molars were selected, sectioned in a mesiodistal direction, and 90 tooth slabs were obtained. The teeth were ground to expose the dentinal hard tissue with 320- and 600-grit silicon carbide disks. The specimens were randomly assigned to nine groups (n = 10). Surfaces for each group were laser irradiated with 30 Hz/70 mJ (2.1 W), 30 Hz/160 mJ (4.8 W), or non-irradiated (control) for each resin cement (SmartCem2, RelyX Unicem, Multilink Automix). All specimens were stored in distilled water at 37°C for 24 h after luting. Shear-bond testing was carried out by using a Universal testing machine with a crosshead speed of 0.5 mm/min. Data were analyzed with one-way ANOVA and post hoc Tukey HSD tests (p < 0.05). RESULTS: The highest bond-strength value was obtained with SmartCem2, which was irradiated with Er:YAG laser (30 Hz/160 mJ). The lowest values were exhibited in the control group of SmartCem2, RelyX Unicem and Multilink Automix, respectively (4.92 ± 1.68, 7.17 ± 2.88, and 7.93 ± 3.05). CONCLUSION: The 2.1-W and 4.8-W laser ablation did not show any statistically difference for RelyX Unicem and Multilink Automix materials. However, in the SmartCem2 group, laser irradiated with 30 Hz/160 mJ application increased the bond-strength values, and the highest bond-strength results were obtained in this group.

Evaluating factors that affect the shade-matching ability of dentists, dental staff members and laypeople.

BACKGROUND: The authors conducted a study to evaluate the influence of dentists' and nondentists' experience, age, sex, eye color and use of eyeglasses or contact lenses on tooth shade-matching ability. METHODS: The authors included 120 participants in this study conducted in Istanbul (periodontists, oral and maxillofacial surgeons, orthodontists, endodontists, pediatric dentists, prosthodontists, restorative dentists, general dentists in private practice, dental technicians, dental assistants, dental assistant students and laypeople). The authors assigned participants to one of three groups: group 1 was composed of prosthodontists, restorative dentists and dental technicians; group 2 consisted of other dental specialists and general dentists; and group 3 included dental assistants, dental assistant students and laypeople. The authors asked participants to match the shades of three artificial maxillary right central incisors (Vitapan acrylic teeth [shades 2L1.5, 1M2, 2R1.5], Vita Zahnfabrik, Bad Säckingen, Germany) by using a shade guide system (Vita Toothguide 3D-Master, Vita Zahnfabrik). They calculated shade matching for the three color components (value, hue, chroma) and analyzed the results by using a chi(2) test. RESULTS: The rate of success in matching the shade for IM2 was 53.3 percent for participants in group 1, 30 percent for participants in group 2 and 20 percent for participants in group 3 (P = .017). However, there were no significant differences between the three groups for shades 2L1.5 and 2R1.5. Professional experience (P = .003) and age (P = .027) were associated with shade-matching success for tooth shade 2L1.5 only. The results showed no statistically significant differences with respect to sex, eye color or use of eyeglasses or contact lenses. CONCLUSIONS: Dental care professionals who routinely performed restorative procedures matched the shades better than did participants in other groups. Professional experience was associated positively with the outcome, while sex, eye color and use of eyeglasses or contact lenses did not have any effect on shade-matching results. CLINICAL IMPLICATIONS: To improve shade-matching skills, clinicians should participate in hands-on courses, continuing education classes and other training programs.

Use of Stafne's mandibular defect in improving retention of mandibular complete dentures.

In 1942, Stafne was the first to report radiographic findings of "static bone cavities" situated near the angle of the mandible. The typical radiographic appearance of Stafne's mandibular defect is a radiolucency below the inferior alveolar canal, between the mandibular premolars and the angle of the mandible. Stafne's mandibular defect ranges from 10 mm to 30 mm in diameter. The size has been shown to be remarkably constant in diagnosed lesions followed over time. In the majority of cases, the lesion is symptomless. Routine surgical exploration is not indicated. It is suggested that the lesion is a radiographic rather than a pathological entity; therefore, consideration was given to making use of these anatomical retentive areas in a prosthetic manner. In this article, a literature review of Stafne's mandibular defect is presented and attempts to improve the retention and stability of the lower complete dentures by using this anatomical entity are described.

Using tissue conditioner material in neutral zone technique.

The looseand unstable lower complete denture is a common problem faced by denture patients. One method used to solve this problem is the neutral zone technique. The neutral zone is the area where the displacing forces of the lips, cheeks and tongue are in balance. In the clinical report presented here, a severely resorbed lower alveolar ridge was treated by determining the neutral zone with tissue conditioner material (Visco-gel, Dentsply Ltd., Weybridge, U.K.). The neutral zone approach with Visco-gel is a more practical and economically feasible treatment for patients having atrophic mandibular ridge.

Persistent sinus tract formation 1 year following cast post-and-core replacements: a case report.

Sinus tracts are paths of drainage for abscesses and can occur both intraorally and extraorally. It is a fact that sinus tracts can heal with proper endodontic therapy. However, there are those types that are persistent and will not respond to any treatment. In these perplexing cases, it may be necessary to elevate a surgical flap to unveil the real etiologic factor. In this article, a case is presented in which 2 persistent and nonhealing sinus tracts were observed around the maxillary left incisor area of a 53-year-old female patient. A difficult cast post-and-core removal had been accomplished to the compromised tooth 1 year previously. A surgical flap had to be reflected, and the cause of the persistent inflammation was determined to be 2 separate root perforations. The granulation tissue was removed, the perforations were sealed with mineral trioxide aggregate, and bone graft was packed in the resorptive bone areas. The symptoms subsided by the time of the 2-week recall. No complaints were noted from the patient during the 4-month follow-up period. This case is a good example that demonstrates the possible complications of post preparation and the necessity of explorative surgery for unveiling the etiologic factor of persistent sinus tract formation.

Investigation of the cleanliness of dentures in a university hospital.

PURPOSE: The purpose of this study was to determine denture cleanliness of a population sample, as well as to investigate denture cleaning habits and attitudes. MATERIALS AND METHODS: Two hundred thirty-four denture-wearing patients were surveyed via a questionnaire to identify types and frequency of use of denture cleaning methods. Patients were also clinically examined to determine denture cleanliness. Dentures were classified as clean, dirty, or extremely dirty based on the level of debris and stain present. The oral mucosa was also examined and rated. RESULTS: The most common regimen employed was brushing with toothpaste (40.59% of patients), while only 1 patient reported soaking the denture in mouthwash. Results showed that 38.9% of patients were not satisfied with their cleansing methods, and 82.9% of patients claimed their dentists did not inform them how to clean their dentures. Only 11.9% of patients had clean dentures. Older dentures tended to be dirtier than newer ones (P = .0001) and had a higher incidence rate of accompanying denture stomatitis (P= .0001). CONCLUSION: In this population sample, most denture wearers did not clean their dentures satisfactorily.