Quintessence International, 04/2005

Purpose: To determine the shear bond strength to dentin of five newer-generation selfetching adhesive systems. Method and materials: Flat bonding sites were prepared on 100 extracted human molar teeth with 600-grit silicon carbide paper, which exposed the dentin. The systems tested were: Clearfil SE Bond; Optibond Solo Plus Self-Etch; Xeno CF III; Tyrian SPE; and Adper Prompt L-Pop. Following application of each adhesive system, bonded assemblies of Z-100 were prepared using a gelatin capsule matrix (n = 20). Ten specimens in each group were debonded after water storage for 24 hours at 37°C, and 10 were stored for at least 30 days, followed by thermocycling for 850 cycles between water baths at 5°C and 55°C, with a dwell time of 1 minute in each bath. Specimens were loaded to failure in an Instron Model 1123 testing machine with a crosshead speed of 5 mm/min. Statistical analysis included a two-way analysis of variance (adhesive and time) and Tukey's post hoc test. Results: Mean shear bond strengths (MPa) at 24 hours were: Clearfil, 26.4 ± 4.2; Optibond, 23.5 ± 4.4; Xeno, 19.5 ± 4.2; Tyrian, 16.5 ± 3.7; and Adper, 15.3 ± 3.3. Mean shear bond strengths (MPa) after storage and thermocycling were: Optibond, 27.5 ± 5.7; Clearfil, 25.5 ± 4.9; Adper, 21.5 ± 3.3; Xeno, 20.4 ± 2.2; and Tyrian, 19.2 ± 6.4. Both adhesive system and storage time were significant factors affecting shear bond strength (P .05). Conclusion: There are significant differences in the in vitro dentin shear bond strength among the self-etching adhesive materials tested. Water storage and thermocycling did not significantly degrade the shear bond strength of the materials in this study. Keywords: adhesive systems, dentin bonding, dentin smear layer, postoperative sensitivity, self-etching adhesives, shear bond strength

A retrospective literature review was carried out to determine the prevalence of hypodontia and current knowledge of associated etiological factors. Reported studies vary widely in their reports of prevalence. The majority are retrospective radiographic studies, and reported rates vary from 2.6% to 11.3%. Racial differences have been determined: in Caucasian studies the mandibular second premolars and maxillary lateral incisors were the most frequently recorded absent and in Asian studies, the mandibular incisor was the most frequently recorded absent. Prevalence rates are higher in females compared to males (3:2, respectively). The association of hypodontia with other systemic conditions and dental anomalies is widely reported. Hypodontia can be regarded as a multifactorial condition. Recent developments in molecular genetics have established the importance of the muscle specific homeobox genes (Msx1 and Msx2) in dental development. Specific genes that are responsible for the more severe types of hypodontia, including ectodermal dysplasia, have been identified by linkage analysis. However, variable expression of the trait suggests a polygenic mode of inheritence with epistatic genes and environmental factors interacting. Keywords: environmental factors, genetic, hypodontia, missing teeth, multifactorial, polygenic

Objective: This study evaluated the biocompatibility of a one-step dentin bonding agent (Prime&Bond 2.1) in pulp capping compared with calcium hydroxide [Ca(OH)2]. Method and materials: Thirty sheep teeth and 20 intact human premolars were used. After cavity preparation, pulp exposure was achieved with a bur (#390). Adhesive pulp capping was performed in 25 teeth (15 sheep and 10 human). In the control group (12 sheep and 10 human teeth), pulps were capped with Ca(OH)2 and all of the cavities in both groups were sealed with resin composite. Three of the sheep teeth were used as intact controls. Teeth were extracted 7 or 90 days following treatment and prepared for histological examination and bacterial detection. Results: At 7 days, severe inflammatory responses underlying the bonding agent and in the coronal pulp were observed with soft tissue disorganization in both human and sheep teeth capped with Prime&Bond 2.1. All of the teeth capped with Ca(OH)2 exhibited mild inflammatory reactions limited with the perforation area. After 90 days with the bonding agent, in 3 of 9 sheep teeth, chronic inflammatory reactions were significant, while slight pulpal reactions were observed in the others and dentin bridge formation in all of the sheep teeth was found. However, in human pulps, persistent, unresolved inflammation with the lack of dentin bridge formation was observed. In the Ca(OH)2 group, pulp repair with dentin bridging was found in all of the teeth, both sheep and human. No correlation was found between the presence of inflammation and bacterial staining using Spearman rank correlation test (P > .05). Conclusion: Prime&Bond 2.1 facilitates enhanced pulp healing and bridge formation in sheep teeth, but in human teeth it was not as successful as Ca(OH)2 as a pulp capping agent. Keywords: biocompatibility, dentin bonding agents, pulpal response

Objectives: To investigate the prevalence and severity of a labial-cervical-vertical groove (LCVG) in maxillary permanent incisors and its effect on the associated gingival tissue. Methods: A total of 600 adolescents (293 boys and 307 girls, mean age 13.6 ± 1.99 years) were randomly selected and examined for the presence of LCVG. The deformity was classified as mild, moderate, or severe according to predetermined criteria. Gingival coverage at the groove site was defined as normal, partial, and irregular. Results: LCVG was found in 27 adolescents (4.5%). It was unilateral in 24 (89%) and bilateral in 3 (11%). The ratio of central to lateral incisors was 29:1. No sexual dimorphism or side prevalence were found. Mild LCVG was found in 22 incisors, moderate LCVG in 7 incisors, and severe LCVG in one incisor. Moderate LCVG was 5 to 6 times more susceptible to partial or irregular coverage of the gingival margin than mild LCVG. The gingival sulcus in teeth with LCVG demonstrated a significant (P = .001) increase in depth compared to non- LCVG teeth (1.55 ± 0.90 mm vs 1.18 ± 0.75 mm). Conclusions: An LCVG is a deformity confined predominantly to a single permanent maxillary central incisor. Its prevalence is not connected with gender. Most LCVGs are mild and often difficult to detect. However, the greater the severity, the more gingival irregularity is associated. This and the increase in sulcus depth in LCVG incisors are adverse predispositions for periodontal sequelae, calling for cautious oral hygiene maintenance. Keywords: congenital deformity, dental deformity, enamel development, gingival contour, gingival margin, labial-cervical-vertical groove, maxillary incisor, periodontal sulcus, tooth development

Objective: To evaluate the role of dental parameters that may contribute in increasing apneic activity in patients with obstructive sleep apnea syndrome (OSAS). Method and materials: A total of 152 subjects (121 males and 31 females ) were examined from October 1999 until September 2001, for sleep disorder symptoms. All patients underwent polysomnography. Any abnormal or unusual features that could inhibit the upper airway of the oral cavity were evaluated by an oral pathologist. Results: Statistical analysis of the independent structural variables and the respiratory disturbance index proved to be significant only in the cases of retropositioned or narrow hard palate with a vertically positioned soft palate, the type of breathing (oral breathing), and the enlarged uvula. Conclusion: The oral soft tissues seem to be more closely associated with OSAS. Therefore, the diagnosis of the structural features of the oral cavity by the clinician is useful to predict apneic activity. Keywords: breathing, mandible, maxilla, oral cavity, sleep apnea, uvula

The pathogenesis of periodontal disease involves the sequential activation of a great variety of components of the host immune response, primarily acting to defend periodontal tissues against bacterial aggression, but also functioning as mediators of tissue destruction. The expression of the disease results from the interaction of host, microbiological agents, and environmental factors. Leukocytes play a critical role in the pathogenesis of the disease, producing different cytokines, chemokines, and other mediators, thus generating a host defense response, as well as inducing tissue inflammation and bone destruction. The aim of this review is to address the role of some inflammatory mediators in response to bacterial aggression in periodontitis. Keywords: chemokine, cytokines, immunology, interleukin, lymphocytes, periodontitis

A 14-year-old, male patient was referred for the treatment of mucositis, idiopathic facial asymmetry, and candidiasis. The patient had been undergoing chemotherapy for 5 years for acute lymphoblastic leukemia. He presented with a swollen face, fever, and generalized symptomatology in the mouth with burning. On physical examination, general signs of poor health, paleness, malnutrition, and jaundice were observed. The extraoral clinical examination showed edema on the right side of the face and cutaneous erythema. On intraoral clinical examination, generalized ulcers with extensive necrosis on the hard palate mucosa were observed, extending to the posterior region. Both free and attached gingivae were ulcerated and edematous with exudation and spontaneous bleeding, mainly in the superior and inferior anterior teeth region. The tongue had no papillae and was coated, due to poor oral hygiene. The patient also presented with carious white lesions and enamel hypoplasia, mouth opening limitation, and foul odor. After exfoliative cytology of the affected areas, the diagnosis was mixed infection by Candida albicans and bacteria. Recommended treatment was antibiotics and antifungal administration, periodontal prophylaxis, topical application of fluor 1.23%, and orientation on and control of proper oral hygiene and diet during the remission phase of the disease. Keywords: acute lymphoblastic leukemia, child, mucositis, oral lesion