Quintessence International, 06/2008

Objective: To evaluate prospectively the clinical performance of 3- to 6-unit zirconia fixed partial dentures (FPDs) after more than 3 years of clinical service. Method and Materials: Since August 2002, 22 conventional all-ceramic FPDs have been inserted in 18 patients. Nineteen of the FPDs were placed with a resin-reinforced glass-ionomer cement. The frameworks were manufactured by a universal CAD/CAM production system, milling the zirconia out of the densely sintered stage. The frameworks were designed as 3-unit (14), 4-unit (3), 5-unit (2), and 6-unit FPDs (3) for the anterior and posterior regions. A new synthetic sintering glass-ceramic was employed as the veneering material. In the follow-up examinations at baseline, 6, 12, 24, and 36 months, 21 FPDs were inspected predominantly for framework fractures and chipping of the veneering material. Besides these parameters, periodontal status, sensitivity of the abutment teeth, esthetic outcome, as well as the incidence of secondary caries, were evaluated. Results: After a mean clinical observation of over 39 months, no framework fracture occurred. However, chipping of the veneering material was reported in 2 cases. Conclusion: All-ceramic FPDs based on zirconia frameworks exhibited satisfactory clinical performance. Parole chiave: CAD/CAM, fixed partial dentures, veneering ceramic, zirconia ceramic

The aim of this article was to review the current evidence on the role of platelet-rich plasma (PRP) in enhancing root-coverage techniques and discuss the rationale for its use in these applications. Sound biologic rationale and a multitude of basic science research support the use of PRP to promote soft tissue healing, although evidence of its role in enhancing periodontal applications, especially root coverage, is limited. Current scientific research has yet to elucidate all of the mechanisms by which PRP can affect soft tissue healing and assess its capacity to stimulate regeneration. Furthermore, clinical evidence on the use of PRP in root-coverage procedures is extremely limited, with only 2 randomized controlled trials published as of May 2007. A pertinent review of medical and dental literature relating to PRP and its role in wound healing and enhancement of root-coverage procedures was performed. Preliminary reports in this area suggest that the potential benefits of PRP in root-coverage procedures may be improved esthetics, decreased patient morbidity, and accelerated wound healing. An appropriate assessment of the effects of PRP and its possible use in enhancing root-coverage procedures cannot be made at this time because of inadequate clinical evidence. Parole chiave: platelet-rich plasma, regeneration, root coverage, soft tissue grafts

Objectives: Obesity and diabetes are the most common nutritional and endocrine disorders in developed and developing countries and are related to immune response alterations. Recent studies suggest an association among diabetes, obesity, and periodontitis. The aim of this study was to evaluate the relationship between neutrophil function alterations and periodontal disease severity of type 2 diabetic chronic periodontitis patients with and without obesity. Method and Materials: A total of 39 chronic periodontitis patients participated in the study. The study population was divided into 4 groups according to body mass index and type 2 diabetes status: (1) 8 type 2 diabetic obese patients, (2) 12 type 2 diabetic patients, (3) 8 obese patients, and (4) 11 systemically healthy patients as a control group. Neutrophil chemotaxis and phagocytosis functions and periodontal status were evaluated. Results: No differences in age, Gingival Index, Plaque Index, percentage of phagocytosis, phagocytic efficiency, and intracellular killing were observed among the groups, but chemotaxis was significantly lower in diabetic groups than the control group and probing depth was significantly higher in diabetic groups than the control group. Obesity did not seem to affect the results significantly for all parameters evaluated. Conclusions: Unlike in patients with type 2 diabetes, neither neutrophil functions nor periodontitis severity seemed to change in obese patients. However, in type 2 diabetic patients, neutrophil chemotaxis alterations seem to affect probing depth measurements. Parole chiave: neutrophil functions, obesity, periodontitis severity, type 2 diabetes mellitus

Garlic is considered a valuable herbal medicine and has been used for centuries for treatment of various ailments. Along with its benefits comes some adverse effects. The present case describes chemical burn of oral mucosa caused by crushed garlic. To relieve toothache, the patient placed crushed garlic cloves in the buccal vestibule overnight and developed garlic burn injury manifesting as slough and ulceration in that region. Diagnosis was made on the basis of definitive history elicited from the patient. Topical anesthetic and antibacterial agents were advised for local application, and systemic analgesic was prescribed. The patient was referred to the Department of Endodontics for further treatment of the toothache. Garlic burn should be considered in the differential diagnosis for chemical burn if the burn is not found to be associated with other common factors, and history taking should include questions regarding use of herbal products, home remedies, and alternative medicine. Possible adverse effects of these methods should be considered. Parole chiave: chemical burn, garlic, garlic burn, self-inflicted injury

Objective: To compare the efficiency of ceramic burs with that of conventional tungsten carbide bud burs in vitro. Method and Materials: Fifty extracted teeth were split in the center of a caries lesion. The 100 specimens were randomly divided into 5 groups. Five clinicians were asked to excavate 10 teeth each: half with ceramic burs and the corresponding half with conventional bud burs. The time needed for caries excavation was measured. Subsequently, the prepared teeth were sectioned to produce histologic specimens, which were analyzed by light microscope after Mallory-Azan staining. The thickness of remaining caries was measured (less or more than 1 mm). The time consumption was analyzed using the paired t test. The results were analyzed for remaining caries and the thickness of the carious layer for every specimen using the nonparametric Wilcoxon test for combined random samples. Results: From 50 teeth, 531 histologic sections were obtained, of which 264 had been treated with ceramic burs and 267 with tungsten carbide burs. Of the sections treated with ceramic burs, 89.8% were caries-free, as were 92.1% of specimens treated with conventional burs. After excavation with ceramic burs, in 3.7% of the sections, the remaining caries was thicker than 1 mm compared with 0% in the control group. The average time to excavate a cavity with ceramic burs was 159.12 seconds (± 68.17) versus 170.62 seconds (± 72.30) with conventional bud burs. None of the recorded differences between the 2 burs was statistically significant (P > .05). Conclusion: In this study, ceramic burs were as effective as conventional tungsten carbide bud burs in dentin caries excavation. Parole chiave: bud bur, caries, CeraBur, ceramic bur, dentin, efficiency, excavation

Objectives: Clinical situations may dictate that Procera AllCeram copings (Nobel Biocare) be fabricated or adjusted to a 0.40-mm coping thickness rather than the standard 0.60 mm. The goal of the present study was to determine the relative strength of 0.40-mm aluminum oxide copings versus standard 0.60-mm aluminum oxide copings and ascertain the effect of luting agents on the load-to-fracture value of the copings. Method and Materials: Forty prefabricated grade 2 titanium dies, premilled to standardized dimensions of a mandibular molar, were scanned using Procera CAD/CAM. Twenty aluminum oxide copings were ordered in the standard 0.60 mm thickness and 20 in 0.40 mm. Two cements were selected. Ten copings of each thickness were cemented to the titanium dies with RelyX Luting (3M ESPE) and 10 of each thickness with Fuji Plus cement (GC). Immediately after cementation, copings were placed under 5-kg static load for 10 minutes and then stored for 1 week in a 100% humidity chamber. At the time of testing, the samples were inspected and placed in a jig to ensure uniform vertical force application. Samples were loaded to fracture at 0.5 mm/min using an Instron universal testing machine. Results were recorded and statistically analyzed using the unpaired Student's t test. Significance was determined at confidence level P = .05. Results: Mean load-to-fracture for the copings cemented with RelyX Luting was 451 N for 0.40-mm and 884 N for 0.60-mm copings, and for the copings cemented with Fuji Plus, 808 N and 1,701 N, respectively. Conclusions: Aluminum oxide copings of 0.60 mm showed significantly greater load-to-fracture values than 0.40 mm copings, regardless of the luting agent used. Within the independent comparisons, copings cemented with Fuji Plus exhibited higher load-to-fracture values than copings cemented with RelyX Luting cement. Parole chiave: aluminum oxide, coping thickness, Fuji Plus cement, load-to-fracture, luting agents, Procera AllCeram copings, RelyX Luting

Hobnail hemangioma is a rare benign vascular tumor. It usually develops in young adults as a single, small, well-circumscribed, angiomatous/pigmented, and flat or exophytic lesion and has a distinctive biphasic histopathologic appearance. Lesions commonly affect the trunk and lower and upper extremities, although head and neck involvement has also been described. Until now, only 3 intraoral cases have been reported. The present article reports a case of hobnail hemangioma on the mandibular left gingiva in a 24-year-old male patient. Awareness of this rare entity rests on the differential diagnosis, which includes retiform hemangioendothelioma, patch-stage Kaposi sarcoma, benign lymphangioendothelioma, and well-differentiated angiosarcoma. Parole chiave: benign, hobnail hemangioma, vascular tumor

Objectives: To compare the cytotoxicity of the polymerized bonding agents Scotchbond 1 (3M ESPE), Prime & Bond NT (Dentsply DeTrey), Xeno III (Dentsply DeTrey), and Clearfil Protect Bond (primer and bond parts; Kuraray) on mouse fibroblast cells. Xeno III was also tested through thin dentin disks. Method and Materials: Near-confluent 3T3 cells were exposed to Dulbecco modified eagle's medium extractions from the above-mentioned agents, and the cell viability (survival rate) was measured using the standard MTT assay and related to the nonexposed controls. Results: All bonding agents were found to be cytotoxic toward the 3T3 cells. Scotchbond 1 (59% survival rate) and Prime & Bond NT (62% survival rate) were not statistically different (Kruskal-Wallis test, P > .05). However, the survival rates of Xeno III (25% through membrane and dentin disks) and Clearfil Protect Bond (35%) were significantly lower than those of the other 2 bonding agents, with Xeno III significantly the most toxic (Kruskal-Wallis test, P .05). Of the 2 parts from Clearfil Protect Bond, the bond part was the least toxic (91% survival rate), but the primer part was very toxic (30% survival rate). Conclusion: In an in vitro culture, all 4 dentin bonding agents were cytotoxic. Xeno III was the most toxic, even through dentin disks. It seems that the cytotoxicities depend on the compositions of the materials tested. The most toxic part of Clearfil Protect Bond was the primer, which contains the antibacterial pyridinium molecule. Parole chiave: bonding agents, cytotoxicity, mouse fibroblast

Objectives: To determine in vitro the effects of 2 commercially available microabrasion compounds (Prema [Premiere Dental Products] and Opalustre [Ultradent]) on human enamel under standardized conditions after treatment periods of 10, 20, 30, and 40 seconds. Nonacidified pumice served as an abrasive control compound. Method and Materials: Mean substance loss was determined by measuring dissolved Ca2+ using atomic absorption spectrophotometry. Differences in the mean surface roughness were profilometrically assessed. These findings were completed with micromorphologic observations using SEM. In addition, color changes after microabrasion were evaluated using the CIE L*a*b* system. Results: Opalustre caused the highest tooth substance loss, followed by the Prema compound and pumice, which showed a lesser substance-removal capacity. These findings were in concordance with the mean surface roughness difference measurements and micromorphologic analyses. Microabrasion did not cause any significant colorimetric changes. Conclusion: Microabrasion should be considered a microinvasive method, and clinical application should be used with caution to avoid excessive substance removal. Subsequent polishing appears crucial to maintain optimal esthetics and avoid surface alterations. Parole chiave: CIE L*a*b*, enamel, microabrasion, surface roughness

Ameloblastic fibroma (AF) is an uncommon benign odontogenic mixed tumor. A case of an AF associated with unerupted and missing teeth is presented. A 13-year-old girl was referred for evaluation of a painless swelling of her right mandible. The most remarkable finding was the resorption of the proximal root of the permanent first molar. The lesion was completely enucleated. Follow-up showed satisfactory bony healing, and the resorbed root was completely surrounded by a continuous layer of intact lamina dura. In most cases, the patient presents to the clinician complaining of an unerupted tooth at the posterior area of the mandible. The most remarkable finding in our case, however, was the coexisting root resorption. This finding could indicate a more aggressive form of AF. AF has a very good prognosis. Malignant transformation is extremely rare. Parole chiave: ameloblastic fibroma, ameloblastic fibrosarcoma, delayed eruption, mandible, root resorption