Editorial The Impact of Study Clubs on Our Patients

The effect of the distance between post and residual gutta-percha on the clinical outcome of endodontic treatment. Moshonov J, Slutzky-Goldberg I, Gottleib A & Peretz B Journal of Endodontics (2005) 31(3) 177-179. (Department of Endodontics, Hadassah School of Dental Medicine, Jerusalem, Israel) After endodontic therapy, teeth are often restored with a post and core. In many cases after post cementation, there is a gap between the apical end of the post and the remaining gutta percha. This study evaluated in vivo the outcome of endodontic therapy in teeth with varying amounts of space between cemented post and gutta percha. A total of 94 patients, who had previously undergone endodontic therapy followed by post and core restoration, were selected. The group consisted of 26 males and 68 females, 23 to 88 years of age. The endodontically treated teeth fit the following criteria: 1. periapical tissue of normal appearance before treatment 2. irreversible pulpitis before treatment 3. pulp exposure during caries removal 4. elective root canal treatment before prosthetic treatment All teeth had been cleaned and shaped under rubber dam isolation and obturated within 1 mm of the radiographic apex, using laterally condensed gutta percha with AH-26 sealer. Cases with complicating factors (separated files, over or underextension of root canal filling, root fracture, residual root canal fill<3 mm) were excluded. The selected cases were divided into three groups, based on measurements from post-treatment radiographs: • Group I: no gap between gutta-percha and post. • Group II: a gap of >0 to 2 mm between gutta-percha and post. • Group III: a gap >2 mm between gutta-percha and post. Follow-up radiographs, taken between one and five years post-treatment, were evaluated according to the following criteria: • Normal: no periapical radiolucency, intact PDL. • Disease: periapical radiolucency or widening of the PDL space. Radiographs were “masked” coronally with cardboard to reduce bias. Clinical outcomes related only to the roots in which posts were placed. The results were as follows: • Group I: 16.7% disease, 83.3% normal. • Group II: 46.4% disease, 53.6% normal. • Group III: 70.6% disease, 29.4% normal. This study illustrates the need to exhibit care when cementing posts in endodontically treated teeth, seating the post properly to eliminate space between the post and residual gutta percha. Five-year follow-up with Procera all-ceramic crowns. Fradeani M, D’Amelio M, Redemangi M & Corrado M (2005) Quintessence International 36(2) 105-113. (University of Milan; private practices in Milan, Mestre, Lomazzo and Monselice, Italy) This study evaluated the clinical performance of Procera AllCeram crowns placed over a five-year period at three different private dental practices. Two-hundred and five Procera AllCeram crowns placed in 106 patients were evaluated over a period ranging from a minimum of six months to a maximum of 60 months, with a mean of 23.52 months. The clinical procedures were performed by three dentists in their private practices. The crowns were fabricated by three dental technicians following manufacturers’ instructions. One hundred and fifty-one crowns were cemented with Panavia 21 TC (Kuraray), 40 with Fuji Plus (GC) and 14 with RelyX Luting (3M). Patients were reexamined by the authors one month after cementation and at three or six-month intervals for the following period. A restoration was considered a failure when it impaired esthetic quality or function, thus necessitating remake of the crown. Patients with severe parafunction, periodontitis, serious gingival inflammation, or poor oral hygiene or caries were excluded from the study. The survival rate was determined with the use of the Kaplan-Meier method, which gave an overall survival rate of 96.7% (100% for the anterior crowns and 95.15% for the posterior crowns). Of the 50 anterior crowns, there were no failures. Of the 155 posterior crowns, there were four failures. All four failures were molars. Two involved fracture of the veneer and alumina coping. One involved fracture of the veneering porcelain only, and one involved de-lamination of the veneering porcelain. The results of this study match results reported in other similar studies on Procera Allceram crowns. Within the limits of this study, it was concluded that the Procera AllCeram system seems to have a good prognosis for the posterior teeth and an excellent prognosis for the anterior teeth. Microhardness of composites in simulated root canals cured with light transmitting posts and glass-fiber reinforced composite posts. Yoldas O & Alaçam T Journal of Endodontics (2005) 31(2) 104-106. (Department of Conservative Dentistry and Endodontics, Çukurova University, Adana, Turkey) This study compared the microhardness of resin composite cured in simulated root canals using light-transmitting plastic posts (LTPP), glass-fiber-reinforced composite posts (GFRCP) and conventional light curing methods (control group). Thirty black plastic cylinders, measuring 15 mm in length and 4 mm in internal diameter, were divided into three groups of 10 specimens each. Tetric Ceram (Ivoclar Vivadent) composite was firmly packed into the simulated canals. The LTTP (No 4, Luminex, Dentatus) and GFRCP (No 1, Postec, Ivoclar Vivodent) with the same diameters (1.5 mm) were inserted into the simulated canals using a parallelometer. All samples were then light cured (Hilux Dental Curing Light, Model No 200, Benlioglu Dental, Inc) with a constant-type exposure at 460 mW/cm2 for 90 seconds. After 24 hours, the plastic cylinders were removed from the samples and a microhardness test was performed using a Micromet Microhardness Tester (MMT-3 Digital Microhardness Tester, Buehler Ltd) with a load of 100 g for 10 seconds. Three test indentations of each sample were made at randomly selected areas of the polymerized resin composite samples at depths of 2, 4, 6, 8, 10, 12 and 14 mm from the light exposed surface. All microhardness measurements were recorded as a Knoop Hardness Number (KHN), and the results were evaluated statistically using a one-way analysis of variance and the Tukey post hoc test between groups. Paired t-tests and repeated measure analysis were used to compare KHN within groups. There was a significant increase in microhardness of the resin composite for both LTPP and GFRCP compared with the control group (p<0.01). The microhardness test could not be performed on the control group due to the lack of polymerization below 4 mm. There were no significant differences in microhardness between LTPP and GFRCP until 10 mm (p>0.01). At 10 mm, the microhardness of resin composite was significantly higher with LTPP than GFRCP (p<0.01). After 10 mm, the microhardness of GFRCP could not be performed because of the lack of polymerization. With increasing distance from the curing tip, the measurement of resin composite microhardness was decreased in all groups.