Quintessence International, 08/2009

Canalicular adenomas are uncommon, benign epithelial neoplasms of the salivary glands that usually involve the upper lip and buccal mucosa of elderly people. Differential diagnosis of the canalicular adenoma versus adenocarcinoma is important, as it may result in unjustified radiotherapy or extensive and aggressive surgery. Despite the benign nature of canalicular adenomas, complete surgical removal and a regular clinical follow-up are recommended. The present article describes the diagnostic procedures, surgical management, and follow-up of a canalicular adenoma involving the palate of a 71-year-old man. Keywords: canalicular adenoma, carbon dioxide laser, minor salivary gland tumor

Ameloblastoma is a fairly common and highly aggressive odontogenic tumor of epithelial origin. It is primarily seen in adults in the third to fifth decade of life. Radiographically, it appears as an expansile lucency with thinned and perforated cortices. It is known to cause root resorption. Because it shares common radiographic features with other lesions, definitive diagnosis is made through histopathologic analysis. This case demonstrates the use of cone beam computed tomography in the differential diagnosis of a large plexiform ameloblastoma in a 29-year-old man. The extent of the lesion and the effect on adjacent structures can be discerned from the images. Additional features seen on these images can aid in the diagnosis. This imaging modality is also useful in surgical planning. Keywords: ameloblastoma, cone beam computed tomography, computed tomography, mandibular odontogenic tumor, maximum intensity projection (MIP), multiplanar reconstruction

Polymerization shrinkage is a major concern for bonded direct posterior restorations. Recently, a new low-shrinkage composite resin restorative material was developed. However, few data are available regarding clinical manipulation of this composite. Siloranebased composites represent an alternative to conventional methacrylate-based composites for direct posterior restorations. This article critically discusses the latest peer-reviewed reports related to polymerization, bonding, polishing, and color stability of silorane composite, focusing on its clinical application. Initial evaluation of this new category of composite material shows acceptable mechanical and physical properties. Keywords: bonding, cationic polymerization, color stability, polymerization, roughness, self-etch adhesive, silorane

Diabetes mellitus is the most prevalent endocrine disease, comprising the third highest cause of disability and morbidity in the Western world. In the past, implant placement was contraindicated in diabetic patients because of increased risk for implant failure and infection. Publications in recent years have shown success rates for dental implants in diabetic patients resembling those of the general population. Other studies, in diabetic patients, as well as in animal models, have shown an increased risk for implant failure. These results raise the question of whether diabetic patients are suitable for dental implant rehabilitation. This article reviews the literature and presents the factors used in assessing the severity of diabetes and its complications, as well as the considerations for rehabilitation planning in these patients. Integration of these factors by the dentist dictates whether as well as what type of implant-supported restoration should be preformed. Keywords: dental implant, diabetes mellitus, implant-supported rehabilitation

Dental trauma can lead to a wide range of injuries of which crown and root fractures are examples. This report describes the management of previously untreated crown- and rootfractured maxillary permanent incisors in an 18-year-old patient. The patient underwent no treatment for 8 years and then presented with the complaint of recurrent pain and swelling. Intraoral examination showed crown fractures in the maxillary right central and left lateral incisors, while radiographic examination revealed large radiolucent lesions related to the periapical area of these teeth and a horizontal root fracture in the middle third of the maxillary left central incisor. Endodontic therapy and periapical surgery were performed for the persistent periapical periodontitis associated with the crown-fractured teeth. Connective tissue healing was detected for the root-fractured tooth. However, because of its proximity to periapical lesions, this root-fractured tooth was also included in the periapical surgery. Follow-up 1 year later showed clinical and radiographic healing. Keywords: crown fracture, dental trauma, periapical lesion, root fracture, surgical endodontic therapy

Objective: To compare the fracture resistance and fracture performance of CAD/CAM zirconia and alloy crowns. Method and Materials: One electrophoretic deposition alumina ceramic (Wolceram, Wolceram) and 4 zirconia-based systems (ce.novation, ce.novation; Cercon, DeguDent; Digizon, Amann Girrbach; and Lava, 3M ESPE) were investigated. A porcelain-fused-to-metal method (Academy, Bego Medical) was used in either conventional casting technique or laser sintering. Sixteen crowns of each material were fabricated and veneered with glass-ceramic as recommended by the manufacturers. Crown and root dimensions were measured, and 8 crowns of each system were adhesively bonded or conventionally cemented. After the crowns were artificially aged in a simulated oral environment (1,200,000 mechanical loads with 50 N; 3,000 thermal cycles with distilled water between 5°C and 55°C; 2 minutes per cycle), fracture resistance and fracture patterns were determined and defect sizes investigated. Results: The fracture force varied between 1,111 N and 2,038 N for conventional cementation and between 1,181 N and 2,295 N for adhesive bonding. No significant differences were found between adhesive and conventional cementations. Fracture patterns presented mostly as a chipping of the veneering, in single cases as a fracture of the core, and in 1 case as a fracture of the tooth. Conclusions: Crown material and cementation do not have any significant influence on the fracture force and fracture performance of all-ceramic and metal-based crowns. Therefore, it may be concluded that adhesive bonding is not necessary for the application of high-strength ceramics. Keywords: adhesive bonding, CAD/CAM, cementation, dental crown, fracture, zirconia

Dental caries on (proximal) tooth surfaces is still a problem in many industrialized countries. The objectives of this review were to present the scientific basis and the principles of the resin infiltration concept, to discuss the inherent clinical applications, and to describe how these backgrounds can be integrated into the concept of minimal intervention dentistry. Data were identified by searches of the Cochrane Registers, Medline, and Scopus. Articles published in English and German through December 2008 were selected, and most up-to-date or relevant references were chosen. Cross-referencing of significant articles identified additionally relevant articles written in other languages and those of historical value. A total of 23 in vitro studies (focusing on penetration depths or demineralization prevention) were found, and 3 clinical studies (involving 122 subjects) could be retrieved; these studies were not comparable. With an increased understanding of the caries process, it is now recognized that demineralized but noncavitated enamel lesions can be arrested or remineralized in many situations. The clinical research evidence on the resin infiltration technique currently is of moderate extent to reach any decisive conclusions; however, based on available laboratory and clinical studies, it seems convincing that resin infiltration of enamel lesions should reduce (or even stop) the progress of white spot lesions. Combining this ultraconservative restorative approach (which is considered microinvasive) with a substantial caries remineralization program may provide therapeutic benefits and significantly reduce both long-term restorative needs and costs, thus complementing the concept of minimal intervention dentistry. Keywords: enamel, fluoride, minimal intervention dentistry, remineralization, resin infiltration, subsurface caries lesion

Objective: To evaluate the expression of extracellular matrix metalloproteinase inducer (EMMPRIN) in healthy and inflamed human gingiva. Method and Materials: Tissue samples from 9 healthy specimens and 21 specimens with chronic periodontitis were collected. The expression of EMMPRIN protein was detected with immunohistochemical staining and Western blot analysis. Results: EMMPRIN was mainly localized in keratinocytes of healthy human gingival tissues; in inflamed gingival tissues, EMMPRIN protein could be detected in keratinocytes, fibroblasts, and inflammatory cells. In addition, EMMPRIN expression level in the inflamed gingiva was increased dramatically compared to that in healthy tissue (P < .05). Using Western blot analysis, EMMPRIN protein was also found to express in both healthy and inflamed gingiva, and the level of EMMPRIN in inflamed gingiva was significantly higher than that in healthy control subjects (P < .05). Conclusion: EMMPRIN might be involved in the physiologic and pathologic states of periodontal tissues. Keywords: extracellular matrix metalloproteinase inducer, gingiva, matrix metalloproteinase, periodontitis

Composite resins and glass-ionomer cements were introduced to dentistry in the 1960s and 1970s, respectively. Since then, there has been a series of modifications to both materials as well as the development other groups claiming intermediate characteristics between the two. The result is a confusion of materials leading to selection problems. While both materials are tooth-colored, there is a considerable difference in their properties, and it is important that each is used in the appropriate situation. Composite resin materials are esthetic and now show acceptable physical strength and wear resistance. However, they are hydrophobic, and therefore more difficult to handle in the oral environment, and cannot support ion migration. Also, the problems of gaining long-term adhesion to dentin have yet to be overcome. On the other hand, glass ionomers are water-based and therefore have the potential for ion migration, both inward and outward from the restoration, leading to a number of advantages. However, they lack the physical properties required for use in loadbearing areas. A logical classification designed to differentiate the materials was first published by McLean et al in 1994, but in the last 15 years, both types of material have undergone further research and modification. This paper is designed to bring the classification up to date so that the operator can make a suitable, evidence-based, choice when selecting a material for any given situation. Keywords: classification, composite resin, glass ionomer, polyacid-modified composite resin, resin-modified glass ionomer

Objective: To compare mandibular morphology between an asymptomatic normal group and a temporomandibular osteoarthritis group. Method and Materials: The study sample consisted of 39 patients with temporomandibular joint osteoarthritis screened by computed tomography and 44 asymptomatic normal subjects. Panoramic radiographs were taken of all subjects. Linear and angular panoramic measurements were taken of the groups' mandibular characteristics, and a t test was used to compare them. Results: The condylar head and condylar and ramal height of the osteoarthritic joints were significantly shorter in the arthritic than in the control group. Moreover, the gonial angles were significantly larger, and the condylar head showed a more distal inclination in the arthritic group. The unilaterally osteoarthritic patients showed significant differences between the affected and contralateral sides of the condylar head and condylar height and the condylar head angle. Conclusions: The present study shows that the condylar head and condylar height were shorter, and the condylar head was more distally inclined in osteoarthritic joints.

Objectives: To examine the cytotoxic effects of MTA and Ca(OH)2 on 3T3 fibroblasts at different time intervals. Methods: Confluent cells were cultured with Ca(OH)2 and MTA in six-well plates. Wells with only fibroblasts served as controls. Cell number and viability were determined after 24 and 48 hours and 7 days of incubation. For cell viability, trypane blue exclusion assay was used. A Leitz inverted microscope was used to observe the morphologic behavior of cells. The proliferation of cells was evaluated by BrdU assay. The results were analyzed with Dunns multiple comparison, Friedman, and Kruskal-Wallis tests. Results: No difference was seen in morphology of cells for either test material. Cells treated with MTA and Ca(OH)2 were reduced in number after 24 and 48 hours, respectively. A statistically significant difference was found in number of viable cells between test groups at 48 hours of incubation. The results of BrdU assay revealed low percentages of capable cells incorporating BrdU. Conclusions: The cytotoxic effects of the test materials- MTA and Ca(OH)2-on 3T3 cell lines were evaluated as cytostatic for 24 and 48 hours, respectively. But this effect was reversible because the incubated cells showed normal cell proliferation at 48 hours and 7 days, respectively; MTA showed a significantly shorter cytotoxic effect on the cells.