Importancia del diagnóstico precoz de los lipomas de células grandes en la región maxilofacial

Lipoma is a benign tumor composed of proliferation of mature fat cells interspersed by fibrous connective tissue, blood vessels and muscles, delimited by a thin capsule. Although it represents a mesenchymal neoplasm most common human body, are rare occurrences in the oral cavity. Presents clinical and histopathological variables that do not alter their prognosis. The pathogenesis is still uncertain, although some authors consider heredity and endocrine disorders as possible causes. Occurs with greater prevalence in obese people, although their metabolism is completely independent of the normal body lipid metabolism. The clinical diagnosis of oral lipoma is the view of a nodular mass, soft, asymptomatic, flat surface, without ulceration and limited growth. The continuing growth of the lesion may cause difficulty in chewing, speech, dental adaptation and change in facial aesthetics of the patient, requiring surgical excision of the lesion. The final diagnosis is by histopathological examination. Aims to present a literature review and clinical cases of a retrospective study of 61 cases of lipomas diagnosed in pathological service between 1978 and 2009, among the 10 573 reports during that same period. It emphasizes the special cases of large lipomas of the maxillofacial region, and the importance of early diagnosis of these lesions. A dental surgeon should be able to diagnose lipomas in an early stage in the maxillofacial area avoiding a massive growth of these lesions.

Internal fit of two all-ceramic systems and metal-ceramic crowns

Objectives: The aim of this study was to investigate the internal fit (IF) of glass-infiltrated alumina (ICA - In-Ceram Alumina), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP - IPS e.max ZirCAD), and metal-ceramic (MC - Ni-Cr alloy) crowns. Material and Methods: Sixty standardized resin-tooth replicas of a maxillary first molar were produced for crown placement and divided into 3 groups (n=20 each) according to the core material used (metal, ICA or Y-TZP). The IF of the crowns was measured using the replica technique, which employs a light body polyvinyl siloxane impression material to simulate the cement layer thickness. The data were analyzed according to the surfaces obtained for the occlusal space (OS), axial space (AS) and total mean (TM) using two-way ANOVA with Tukey's multiple comparison test (p<0.05). Results: No differences among the different areas were detected in the MC group. For the Y-TZP and ICA groups, AS was statistically lower than both OS and TM. No differences in AS were observed among the groups. However, OS and TM showed significantly higher values for ICA and Y-TZP groups than MC group. Comparisons of ICA and Y-TZP revealed that OS was significantly lower for Y-TZP group, whereas no differences were observed for TM. Conclusions: The total mean achieved by all groups was within the range of clinical acceptability. However, the metal-ceramic group demonstrated significantly lower values than the all-ceramic groups, especially in OS.

Internal fit of two all-ceramic systems and metal-ceramic crowns

OBJECTIVES: The aim of this study was to investigate the internal fit (IF) of glass-infiltrated alumina (ICA - In-Ceram Alumina), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP - IPS e.max ZirCAD), and metal-ceramic (MC - Ni-Cr alloy) crowns. MATERIAL AND METHODS: Sixty standardized resin-tooth replicas of a maxillary first molar were produced for crown placement and divided into 3 groups (n=20 each) according to the core material used (metal, ICA or Y-TZP). The IF of the crowns was measured using the replica technique, which employs a light body polyvinyl siloxane impression material to simulate the cement layer thickness. The data were analyzed according to the surfaces obtained for the occlusal space (OS), axial space (AS) and total mean (TM) using two-way ANOVA with Tukey s multiple comparison test (p<0.05). RESULTS: No differences among the different areas were detected in the MC group. For the Y-TZP and ICA groups, AS was statistically lower than both OS and TM. No differences in AS were observed among the groups. However, OS and TM showed significantly higher values for ICA and Y-TZP groups than MC group. Comparisons of ICA and Y-TZP revealed that OS was significantly lower for Y-TZP group, whereas no differences were observed for TM. CONCLUSIONS: The total mean achieved by all groups was within the range of clinical acceptability. However, the metal-ceramic group demonstrated significantly lower values than the all-ceramic groups, especially in OS.

Marginal adaptation and performance of bioactive dental restorative materials in deciduous and young permanent teeth

Objective: The aim of this study was to investigate the adaptation of different types of restorations towards deciduous and young permanent teeth. Materials and Methods: Class V cavities were prepared in deciduous and young permanent teeth and filled with different materials (a conventional glass-ionomer, a resin-modified glass-ionomer, a poly-acid-modified composite resin and a conventional composite resin). Specimens were aged in artificial saliva for 1, 6, 12 and 18 months, then examined by SEM. Results: The composite resin and the polyacid-modified composite had better marginal adaptation than the glass-ionomers,though microcracks developed in the enamel of the tooth. The glass-ionomers showed inferior marginal quality and durability, but no microcracking of the enamel. The margins of the resin-modified glass-ionomer were slightly superior to the conventional glass-ionomer. Conditioning improved the adaptation of the composite resin, but the type of tooth made little or no difference to the performance of the restorative material. All materials were associated with the formation of crystals in the gaps between the filling and the tooth; the quantity and shape of these crystals varied with the material. Conclusions: Resin-based materials are generally better at forming sound, durable margins in deciduous and young permanent teeth than cements, but are associated with microcracks in the enamel. All fluoride-releasing materials give rise to crystalline deposits.

Comparison of Composite Placement Techniques by Recently Qualified Dental Practitioners.

Objectives: To evaluate the placement of composite materials by new graduates using three alternative placement techniques.Methods: A cohort of 34 recently qualified graduates were asked to restore class II interproximal cavities in plastic teeth using three different techniques.

(i) A conventional incremental filling technique (Herculite XRV) using increments no larger than 2-mm with an initial layer on the cervical floor of the box of 1-mm.
(ii) Flowable bulk fill technique (Dentsply SDR) bulk fill placement in a 3-mm layer followed by an incremental fill of a microhybrid resin
(iii) Bulk fill (Kerr Sonicfill) which involved restorations placed in a 5-mm layer.

The operators were instructed in each technique, didactically and with a hands-on demonstration, prior to restoration placement.
All restorations were cured according to manufacturer’s recommendations. Each participant restored 3 teeth, 1 tooth per treatment technique.
The restorations were evaluated using modified USPHS criteria to assess both the marginal adaptation and the surface texture of the restorations. Blind evaluations were carried out independently by two examiners with the aid of magnification (loupes X2.5). Examiners were standardized prior to evaluation.
Results: Gaps between the tooth margins and the restoration or between the layers of the restoration were found in 13 of Group (i), 3 of Group (ii), and 4 of Group (iii)
Statistical analysis revealed a significant difference between the incrementally filled group (i) and the flowable bulk-fill group (ii) (p=0.0043) and between the incrementally filled (i) and the bulk fill groups (iii) (p=0.012) and no statistical difference (p=0.69) between the bulk filled groups Conclusions: Bulk fill techniques may result in a more satisfactory seal of the cavity margins when restoring with composite.

Osteocyte Density in the Peri-Implant Bone of Immediately Loaded and Submerged Dental Implants

Background: The role of osteocytes in bone structure and function remains partially unresolved. Their participation in mechanotransduction, i.e., the conversion of a physical stimulus into a cellular response, has been hypothesized. The present study was an evaluation of the osteocyte density in the peri-implant bone of immediately loaded and submerged dental implants. Methods: Fourteen male patients were included in the study; all of them were partially edentulous and needed a posterior mandibular restoration. Implants were inserted in these areas; half of the sample was loaded immediately (included in a fixed provisional prosthesis on the same day as implant surgery), whereas the other half was left to heal submerged. Fourteen implants (seven immediately loaded and seven unloaded) were retrieved with a trephine after a healing period of 8 weeks. The specimens were treated to obtain thin ground sections, and histomorphometry was used to evaluate the osteocyte index in the peri-implant bone. Results: A higher and statistically significant number of osteocytes was found in the peri-implant bone around immediately loaded implants (P=0.0081). A correlation between the percentage of bone-implant contact and osteocyte density was found for immediately loaded implants (P=0.0480) but not for submerged implants (P=0.2667). Conclusion: The higher number of osteocytes in the peri-implant bone around immediately loaded implants could be related to the functional adaptation required by the loading stimulus, which also explains the hypothesized involvement of the osteocytes in the maintenance of the bone matrix. J Periodontol 2009;80:499-504.