A simple model to demonstrate the electronic apex locator

AIM: To describe and evaluate a newly developed model for demonstrating and teaching the use of electronic apex locators. SUMMARY: A phantom model, master jaw model and extracted human teeth were used to construct the demonstration model with alginate impression material as the periapical conductive medium. The model was validated in a series of length determinations with apical foramina enlarged to 0.20, 0.30 and 0.45 mm diameter, and the stability of the model was evaluated up to 45 h after construction. All evaluations were conducted with the Root ZX apex locator with 2.65 and 5.25% NaOCl in the canals. Most length measurements were within 1 mm of actual root length (range: -2.2 to +0.21 mm) and did not change significantly over 45 h for teeth with foramina of 0.3 mm or less. Measurements for teeth with wide (0.45 mm) apices were stable up to 28 h. NaOCl concentration did not significantly affect the readings. KEY LEARNING POINTS: A simple, inexpensive model can be manufactured from plastic dental jaws, natural teeth and alginate impression material to demonstrate electronic working length measurement. The model is stable for many hours and provides consistent results with different concentrations of NaOCl in the canal and various apical diameters. The model is a useful teaching aid but needs further evaluation and refinement before use in research applications.     

A prospective multicenter evaluation of 1,583 3i implants: 1- to 5-year data

PURPOSE: The purpose of this prospective multicenter study was to evaluate the efficacy of 3i threaded implants for the treatment of edentulous patients in a 1- to 5-year period. This article reports the total data and global results of 3 threaded designs of 3i implants: self-tapping, ICE, and Osseotite. MATERIALS AND METHODS: A total of 1,583 implants (619 ICE, 545 Osseotite, and 419 self-tapping) were placed between 1995 and 1999 in 528 patients at 13 European clinical centers. The average age of the patients was 53.6 years. Clinical and radiographic evaluations were performed annually for up to 5 years. RESULTS: Of the total implants, 707 were placed in the maxilla and 876 in the mandible. A total of 1,162 implants were placed in posterior segments. Forty-eight implants were lost to follow-up and 55 were failures. The most frequent prosthetic indication was the short-span fixed prosthesis (440 cases), followed by 172 single-tooth replacements, 56 long-span prostheses, and 4 overdentures. Radiographic evaluation after 6, 12, and 24 months of implant loading showed, respectively, mean crestal bone loss of 0.04 +/- 1.3 mm, 0.12 +/- 1.6 mm, and 0.2 +/- 1.7 mm. A cumulative survival rate of 96.5% was observed 5 years after implant placement, with 97.2% survival in the maxilla and 95.8% in the mandible. The survival rate was similar in anterior (96.7%) and posterior (96.5%) segments. DISCUSSION: A total of 55 failures were reported in this study with 47 early failures and 8 late failures. The rate of late failures is of utmost importance for the restorative dentist. CONCLUSION: This clinical study gives evidence of very high success rates using 3 threaded designs of 3i implants.     

Microhardness of composites in simulated root canals cured with light transmitting posts and glass-fiber reinforced composite posts

The aim of this study was to evaluate the depth of cure of composite resin cured within simulated root canals by means of light-transmitting plastic posts, glass-fiber-reinforced composite posts, and conventional light curing method. Thirty black plastic cylinders measuring 15 mm in length and 4 mm in internal diameter were divided into three groups. The composite resin was packed into simulated canals. The light-transmitting plastic posts and glass-fiber-reinforced composite posts were inserted into simulated canals and light cured for 90 seconds. The control group was light cured directly. To ensure continual change of material properties by increasing the length of material, a surface microhardness test was done 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, and 14 mm from the light exposure surface. The results showed a significant increase in microhardness of composite resin (depth of cure) for both light-transmitting plastic posts and glass-fiber-reinforced composite posts compared with the control group. The microhardness of composite resin was also significantly higher with light-transmitting plastic posts than glass-fiber-reinforced composite posts after 8 mm.     

Treatment of gingival fibromatosis associated with Zimmermann-Laband syndrome

BACKGROUND: Gingival fibromatosis is a rare condition characterized by a generalized enlargement of the buccal and lingual aspects of the attached and marginal gingiva. METHODS: This case report describes the periodontal management of a 13-year-old female patient with gingival fibromatosis associated with Zimmermann-Laband syndrome. The patient presented with gingival enlargement involving the maxillary and the mandibular arches, anterior open bite, and non-erupted teeth. Periodontal treatment included gingivectomy in all four quadrants. RESULTS: Histopathologic evaluation of the excised tissue supported the diagnosis of gingival fibromatosis. A significant improvement in esthetic appearance and eruption of the non-erupted teeth were obtained. The patient was referred for appropriate orthodontic treatment and has been closely followed for the earliest signs of recurrence of gingival enlargement. CONCLUSIONS: The successful therapy for gingival fibromatosis depends on correctly identifying the etiological factors and improving the impaired function and esthetic appearance through surgical intervention and adjunctive orthodontics. Maintaining treatment results depends on preservation of periodontal health.     

Clinical, radiographic, biochemical and histological findings of florid cemento-osseous dysplasia and report of a case

Florid cemento-osseous dysplasia has been described as a condition that characteristically affects the jaws of middle-aged black women. It usually manifests as multiple radiopaque cementum-like masses distributed throughout the jaws. This condition has also been classified as gigantiform cementoma, chronic sclerosing osteomyelitis, sclerosing osteitis, multiple estenosis and sclerotic cemental masses. The authors present a case of an uncomplicated florid cemento-osseous dysplasia in a 48-year-old black woman. Multiple sclerotic masses with radiolucent border in the mandible were identified radiographically. Histopathologic findings revealed formation of calcified dense sclerotic masses similar to cementum. All clinical, radiographic, biochemical and histological features were suggestive of the diagnosis of florid cemento-osseous dysplasia.     

Evaluation of bond strength of various margin ceramics to a zirconia ceramic

OBJECTIVE: This study evaluated the bond strengths of four different margin ceramics based on fluoroapatite and feldspath to a zirconia ceramic. METHODS: Zirconia cores (Zirconzahn) (N=28, n=7/margin ceramic group) were fabricated according to the manufacturers' instructions (diameter: 4mm; thickness: 2mm) and ultrasonically cleaned. Four different margin ceramics (thickness: 5mm) (Cerabien Zr, Noritake; Ceramco PFZ, Ceramco; e.max, Ivoclar Vivadent and Triceram, Dentaurum) were vibrated and condensed in a stainless steel mould and fired onto their zirconia cores. After trying the specimens in the mould for minor adjustments, they were again ultrasonically cleaned and embedded in PMMA. The specimens were stored in distilled water at 37 degrees C for 1 week and shear bond strength (MPa+/-S.D.) tests were performed in a universal testing machine (crosshead speed: 0.5mm/min). Failure modes were recorded under SEM. RESULTS: Significant effect of margin ceramic types were found on the bond strength values (P<0.05). The mean bond strength values of Ceramco margin ceramic to zirconia was significantly lower (25.4+/-4.5MPa) (P<0.05) than those of Cerabien (31.6+/-6.4MPa), e.max (35.9+/-8.4MPa), and Triceram margin ceramic (38.8+/-7.1MPa) systems. CONCLUSIONS: Margin ceramics, compatible with zirconia framework material tested in the present study, exhibited high bond strength values. Variations in thermal expansion coefficients might influence their bond strength values.