Quintessence International, 09/2006

Ectopic eruption is a disturbance in which the tooth does not follow its usual course. Among its more important etiologic factors are macrodontism, shortened arch length, posterior positioning of the maxilla, atypical eruption angle, and genetic factors. This article reports a rare case of ectopic eruption of 4 permanent teeth, maxillary central incisors and mandibular first molars, in a child aged 7 years and 11 months, in which the treatment consisted of extracting the maxillary primary central incisors and making an orthodontic intervention on the mandibular arch. A bilateral fixed appliance containing 2 hooks with loops, 1 buccal and the other lingual, was placed on the mandibular primary first molars. The hooks were activated in a niche made of light-curing resin on the occlusal surface of the mandibular permanent molars, to bring about the distal drift of these teeth. After 6 months, complete eruption of the mandibular permanent molars occurred, and a slight displacement of the maxillary permanent central incisors toward the median line was noted. The importance of early, adequate treatment is discussed. Keywords: tooth eruption, ectopic; orthodontics, interceptive; dentition, permanent; molar; incisor; pediatric dentistry

Objectives: The purpose of this prospective clinical cohort study was to determine the success rate of 3- to 5-unit posterior fixed partial dentures (FPDs) with zirconia frameworks after 3 years of function. Method and Materials: Forty-five patients in need of at least 1 FPD to replace 1 to 3 posterior teeth were included. The frameworks were produced by means of a prototype computer-assisted manufacture system. They were milled with a precisely calculated increase in size out of presintered zirconia blanks and subsequently shrunk to the required size. Fifty-seven FPDs were cemented using either Variolink or Panavia TC cement. Clinical and radiographic examinations were performed at baseline, 12, 24, and 36 months after cementation. Statistical analysis was performed by descriptive statistics and the Kaplan-Meier survival analysis. Comparisons of probing depth, Plaque Index, and bleeding on probing between test (abutment) and control (contralateral) teeth were done with the McNemar test. Results: Thirty-six patients with 46 FPDs were available for examination after 36 months. No fractures occurred, rendering a 100% success rate of the zirconia frameworks. Seven FPDs had to be replaced because of biologic and technical problems. The survival rate, therefore, was 84.8%. Secondary caries was found in 10.9% of the FPDs, and chipping of the veneering ceramic was found in 13.0%. There were no significant differences regarding the probing depth in test and control teeth. Conclusion: Zirconia frameworks demonstrated sufficient stability for replacement of posterior teeth. However, the high rates of technical problems should be reduced by further developments of the prototype processing technology. Keywords: ceramic, fixed partial denture, framework, zirconia

Objective: The purpose of this clinical trial was to evaluate the efficacy of 2 over-the-counter whitening systems: a liquid whitening gel (5.9% hydrogen peroxide, twice a day for 15 minutes), and a sodium chlorite-based whitening gel applied in a tray system (10 minutes twice a day). Method and Materials: Sixty volunteers (minimum shade A3 on 1 maxillary tooth) were selected to participate in this single-blind (examiner-blinded), single-center, 2-group trial. The subjects were randomly divided into 2 groups (n = 30 each) and instructed to bleach their teeth for 2 weeks. Efficacy was measured using the Vita Classical shade guide and a spectrophotometer at baseline, as well as after 2 weeks and 6 months. Results: For the subjectively measured tooth shades, improvement for maxillary canines was 2.03 ± 3.67 tooth shades in group 1 and 1.08 ± 2.19 tooth shades in group 2 after 2 weeks; the maxillary incisors revealed a tooth shade improvement of 0.83 ± 1.71 tabs in group 1 and 0.73 ± 2.22 tabs in group 2 (P < .05, except maxillary incisors in group 2; t test). Objectively measured tooth shade scores revealed a change of 0 ± 0.25 tooth shade tabs (P > .05). Conclusions: The bleaching gel containing hydrogen peroxide achieved a slight improvement, and the sodium chlorite-based bleaching gel achieved only a small tooth color improvement. Moreover, subjectively and objectively measured tooth shades revealed considerably different results in the clinical situation. Keywords: home tooth bleaching, hydrogen peroxide, over-the-counter bleaching products, randomized clinical trial, sodium chlorite

It is well documented that oral squamous cell carcinoma (OSCC) is related to risk factors such as smoking and alcohol consumption as well as premalignant lesions and conditions such as leukoplakia, oral lichen planus (OLP), and previous malignancy of the upper respiratory system and gastrointestinal tract. Osseointegrated dental implants are rarely reported in association with OSCC. This article presents 2 cases of OSCC adjacent to dental implants in patients at risk for oral cancer-1 was a heavy smoker with OLP; the other had a history of previous oral and colon cancer. Six additional cases of malignancy adjacent to dental implants were retrieved from the literature; the majority of cases had at least 1 recognized risk factor for oral cancer. Although such cases are rarely reported, patients at risk for oral cancer, especially those with multiple existing risk factors, that present with failing dental implants should be thoroughly evaluated to rule out the presence of malignancy disguised as peri-implant disease. Keywords: carcinoma, dental implants, lichen planus, smoking

Objective: The aim of this study was to evaluate color compatibility of corresponding resin composite shades keyed to Vitapan Classical shade guide (Vita). Method and Materials: Twenty-one shades of 6 commercial resin composites were analyzed. Specimens (n = 5) were made as disks, 11 mm in diameter and 2 mm thick, using cylindrical molds. Specimens were polymerized according to manufacturers' suggestions using a light-curing unit. Data were collected using a spectrophotometer and analyzed using the appropriate color difference metric equations. A total color difference (DE*ab) greater than or equal to 3.7 was considered a mismatch. Analysis of variance and Fisher's probable least-squares difference (PLSD) test. intervals for comparison of means were calculated at the .05 level of significance. Results: Mean DE*ab values among A2, B2, C2, and opaque A2 shade pairs were 4.4 (1.8), 7.3 (3.2), 5.6 (2.8), and 6.5 (1.8), respectively, while the mean color difference for all the pairs compared was 5.8 (2.8). For A2 shades, DL*, Da*ab, and Db*ab values ranged by 5.3, 2.3, and 6.7, respectively. Corresponding values for B2 shades ranged by 10.5, 2.2, and 11.5; 7.9, 2.2, and 4.3 for C2 shades; and 7.9, 1.4, and 4.4 for opaque A2 shades. Fisher's PLSD critical intervals for comparing DE*ab values among the shades and composite pairs were 0.07 and 0.15, respectively (P < .0001, power 1.00). Conclusion: Overall, poor color compatibility of shade pairs of identical shade designation was recorded. The best color match was recorded for A2 shade pairs, followed by C2, B2, and opaque A2 shade pairs. Keywords: color, color measurement, dental materials, optical properties, resin composite, standardization, shade

Larva migrans is a condition caused by subcutaneous or visceral migration of parasite larvae, usually Ancylostoma braziliense, and is characterized by pruriginous or serpiginous lesions. This article describes a case of larva migrans involving the oral mucosa in a 24-year-old woman. Keywords: oral larva migrans, oral parasite larvae, subcutaneous oral lesion

This case report outlines an alternative oral rehabilitation treatment of a 4-year-old boy with hypodontia and conical tooth shape, which along with other characteristics led to a suspicious ectodermal dysplasia diagnosis. Diagnostic waxup and a silicone matrix formed the basis to the successful reconstruction of the anterior teeth with resin composite. Addition-ally, removable partial dentures were fabricated to improve esthetics and chewing ability. Positive psychologic influence of this alternative treatment on this patient is also discussed. Keywords: conical teeth, ectodermal dysplasia, hypodontia, oral rehabilitation, removable partial denture, resin composite

Objective: The aim of this in vitro study was to examine the fracture strength of metal-free 3-unit adhesive fixed partial dentures (AFPDs) bonded to mandibular incisors. Method and Materials: Extracted human incisors were positioned in pairs in polymethyl methacrylate resin simulating a clinical anterior situation. Their lingual sides were prepared for adhesive retainers with surfaces and finishing lines in enamel. Eight 3-unit AFPDs were made on master casts per material system: Connect/belleGlass (Girrbach), StickNet (StickTech)/Sinfony (3M Espe), and Empress 2 (Ivoclar Vivadent). The dentures were bonded adhesively using the dual-curing system ED Primer/Panavia F (Kuraray Europe) and aged by thermocycling (6,000 3 5¡ãC/55¡ãC H2O; 2 minutes each cycle) and mechanical loading (1.2 3 106 3 20 N with 1.66 Hz) in an artificial oral environment representing a wearing period of 5 years. The fracture strength was determined in a universal testing machine (UTM 1446, Zwick) at a speed of 1 mm/min, applying the load buccoincisally on the pontics. The different forms of failure were described optically. Medians (25th/75th percentiles) of the fracture results were calculated. Statistical analysis was performed using Mann-Whitney U and Kruskal-Wallis tests (P ¡Ü .05). Results: Five StickNet/Sinfony AFPDs and 7 Empress 2 restorations failed in the artificial oral environment. The remaining Empress 2 dentures showed the highest medians of fracture forces (339 [200/506] N) compared to Connect/belleGlass (257 [242/310] N) and StickNet/Sinfony (256 [204/347] N). Statistical comparisons showed no significant differences. Conclusion: Only Connect/belleGlass and Empress 2 showed sufficient resistance against mastication forces. Keywords: fixed partial denture, fracture strength, metal free, minimally invasive

A case is presented of fractured genial tubercles, revealed by occlusal radiography, in a 63-year-old edentulous woman. Isolated fractures are a rare event that may present with pain and edema in the floor of the mouth. It occurs mainly in patients wearing a complete denture when the mandible is atrophied and the genial tubercles are hypertrophied. Only 11 case reports have been found in the English literature. Keywords: fracture, genial tubercles, radiography