Flexural strength of provisional crown and fixed partial denture resins

STATEMENT OF PROBLEM: Provisional prostheses are subject to flexure under function. Selection of the appropriate material for their fabrication is difficult given the limited evidence-based information on the flexural strength of provisional resins. PURPOSE: This study compared the flexural strength of 5 methacrylate-based resins and 8 bis-acryl resins used to fabricate provisional crowns and fixed partial dentures. MATERIAL AND METHODS: Bar-type specimens were fabricated according to American National Standards Institute/American Dental Association specification 27. After being immersed in artificial saliva at 37 degrees C for 10 days, the specimens were fractured under 3-point loading in a universal testing machine at a crosshead speed of 0.75 mm/min. Maximal loads to fracture in Newtons were recorded. Mean flexural strengths were calculated in MPa (n = 10 per group). Comparisons were made with analysis of variance and Duncan's multiple range test (P<.05). RESULTS: Mean flexural strengths ranged from 56.2 to 123.6 MPa. There were 4 statistically similar groups. The group with the highest strengths consisted of 4 bis-acryl materials (Provipont, Integrity, Protemp 3 Garant, and Luxatemp). CONCLUSION: Within the limitations of this study, flexural strengths were material- rather than category-specific. Some, but not all, bis-acryl resins demonstrated significantly superior flexural strength over traditional methacrylate resins.     

Postoperative complaints following impacted mandibular third molar surgery in Ile-Ife, Nigeria.

An investigation into the pattern of complaints lodged by patients after impacted mandibular third molar surgery was done in a Nigerian teaching hospital over a period of 3 years. One hundred and twenty seven records were retrieved. Pericoronitis (71.2%), pulpitis (17.6%) and periodontitis (11.2%) were the reasons for surgery. No third molar surgery was done for prophylactic or orthodontic reasons. Sixty-one complaints were lodged by 49 (38.6%) patients on day 1, and 37 complaints by 35 patients on day 7. These complaints were verified by the findings of the examining clinician. Pain, swelling and trismus were the commonest complaints. A significant association (P = 0.042) was found between patients' complaints on the first postoperative day and the drug combination given. Similarly, there was a significant relationship (P = 0.0055) between the type of analgesics prescribed and the presence of postoperative pain. No significant relationship was however found between the complaints and patients' age, indication for extraction, impaction type and method of impacted tooth removal. Although the findings of this retrospective study are limited in their comparability, they suggest the need for an appraisal of pain management in patients undergoing mandibular third molar surgery in our hospital. Consequently, there should be a reduction in complaint rate thereby making selective review appointment on the first postoperative day feasible.     

The effect of acid etching on vascular diameter of pulp-vessels in rat incisor (vitalmicroscopic study)

Conditioning agents used on dentin with composite materials are biologically active and may have deleterious effects on the pulpal microcirculation. No data are available on the immediate vascular effect of etching materials applied on a constant thin pulpal dentin. In this study the authors examined whether the application of 36% phosphoric acid (Conditioner 36, 15 seconds) or itakonic acid with 10% maleic acid (NRC Non-Rinse Conditioner, 20 seconds), as recommended by the manufacturers, alters the blood circulation in the pulp of the rat's lower incisors. The effect of prolonged etching time (60 seconds) was also assessed (Conditioner 36). The application of saline served as the untreated control. The technique of vitalmicroscopy was used on the first lower incisor of 40 (10-10 in each group) male Sprague-Dawley rats (weighing 350 +/- 8 g SE) to record the changes in vessel diameter prior to and at 5, 15, 30 and 60 minutes after the test materials were administered on the dentin. In the control rats, the vessel diameter was stable during the entire experiment. Acid conditioning as recommended by the manufacturers tended to cause vasodilatation, though these alterations were statistically not significant when compared to the control group (ANOVA, p > 0.05). After prolonged etching time (Conditioner 36, 60 seconds) significant vasoconstriction (-14.4 +/- 6.13; -10.59 +/- 4.2; -11.96 +/- 6.75; -5.49 +/- 5.78%) was observed (ANOVA, p < 0.05). In this group, stasis developed in pulpal blood circulation in 40% of rats (Cochran's-Q test, p < 0.05), gas-bubble formation was observed in 30% and the disappearance of the pulpal wall occurred in 20%. These results suggest that exposition time with acid is crucial to the pulpal microcirculation. That is, acid conditioning applied as indicated (for 15-20 seconds) onto a very thin layer of dentin only slightly affects the blood supply to the dental pulp; however, prolonged etching time (for 60 seconds) results in immediate failure of microcirculation in the dental pulp of rats.     

Glandular odontogenic cyst: a challenge in diagnosis and treatment

The present review analyzes the accumulated data from all cases of glandular odontogenic cyst (GOC) reported in the English language literature. In the 20 years since it was first described, 111 cases have been reported, an incidence of 0.2% of odontogenic cysts. The age range is 14-75, mean 45.7, with a M/F ratio of 1.3:1. GOC has a predilection for the mandible (70%), affecting both anterior and posterior areas. It is typically radiolucent, well defined, either unilocular (53.8%) or multilocular (46.2%). Frequent perforation (61%) and of thinning of cortical plates (24.4%) indicate aggressiveness. Sufficient follow-up indicates that 30% of cases can recur. Treatment by enucleation or curettage carries the highest risk for recurrence, especially in large and multilocular lesions. Peripheral osteoectomy or marginal resection can eliminate the risk. Defined criteria for microscopic diagnosis are described, which in addition to Ki67 and p53 can help in differentiating GOC from lesions with histological similarities (cysts with mucous metaplasia, botryoid and surgical ciliated cysts, low-grade mucoepidermoid carcinoma). Definite diagnosis may not be possible in small incisional biopsies due to the focal presentation of characteristic features required for diagnosis. There is now evidence to support an odontogenic rather than a sialogenic origin.     

Accuracy of the Third Molar Eruption Predictor in predicting eruption

OBJECTIVE: To evaluate the possibility of applying the Third Molar Eruption Predictor to all panoramic radiographs. STUDY DESIGN: Panoramic radiographs were retrospectively analyzed from a 4-year follow-up study of third molars carried out at the University of Copenhagen, Denmark. The radiographs, taken at a mean age of 20.6 years, included 45 unerupted or partially erupted mandibular third molars in 28 subjects. Because the device was calibrated both with simple proportions and by use of the methods of Bayes' Decision Theory, the separation point of the device was therefore adjusted at 12 mm from the distal surface of the second molar. RESULTS: The predictions of future eruption or impaction made with the calibrated device and the actual clinical outcome 4 years later were in conformity for 80% of the mandibular third molars. CONCLUSION: The Third Molar Eruption Predictor may be applied to all panoramic radiographs, but it seems to require calibration before use.     

Comparison of four methods of assessing root surface debridement

BACKGROUND: While there is great interest in measuring the efficacy of root surface debridement, there is little consensus on how this might be best achieved. The aim of this study was therefore to compare four different methods of assessing root surface debridement in their ability to discriminate between ultrasonically instrumented root surfaces and non-instrumented control surfaces. METHODS: Single-session subgingival root debridement was performed by an experienced operator on 30 teeth prior to their extraction. Following extraction, efficacy of root surface debridement was measured by percentage of remaining calculus, instrument efficiency, modified instrument efficiency, and percentage apical plaque border. In addition, the effect of probing depth landmark (apical plaque border versus connective tissue attachment) on outcomes was assessed. RESULTS: The results indicated that percentage apical plaque border demonstrated highly statistically significant differences between instrumented and control surfaces (P= 0.02). No other assessment method was able to discriminate between instrumented and non-instrumented surfaces, and this may be a function of the low amount of root surface calculus in the experimental sample. In addition, choice of probing depth landmark had a notable effect on the outcomes for instrument efficiency and modified instrument efficiency. Ninety-five percent limits of agreement of interexaminer reproducibility were found to be much higher than intra-examiner measurement for all four methods of assessment. CONCLUSIONS: Percentage apical plaque border appeared to be potentially more useful than other methods for assessing the efficacy of debridement of periodontally involved root surfaces, particularly for measuring instrument penetrability.     

Referral patterns and the referral system for oral surgery care. Part 2: The referral system and telemedicine

OBJECTIVE: To investigate GDP opinions of the current referral system and to investigate the need and demand for telemedicine in oral surgery referrals. DESIGN: Postal questionnaire. SETTING: 400 GDPs in Greater Manchester. RESULTS: 84% participation rate. 48% were not satisfied overall with the service of their current specialist oral surgery referral site. The principal reason was the length of the waiting time for consultation and treatment. Distance for patients to travel to the specialist unit was also of concern, even though most patients (89%) travelled short distances (return journey of twelve miles or less). 23% of respondents wished to improve their ability to communicate with the oral surgeon and 70% wanted involvement in the patient consultation. Both of these requirements were more likely in younger practitioners. CONCLUSION: There is a need and demand for change in the referral system for oral surgery specialist care. Telemedicine could conceivably be one way to improve access to specialist oral surgery care.