Soft‐Tissue Alterations Following Exposure to Tooth‐Whitening Agents

Background: Tooth‐whitening agents are widely used, either as self‐application products or under the supervision of a dentist. These products may be associated with transient gross morphologic changes in oral soft tissues. However, their potential effects on human keratinocytes and fibroblasts in a stratified squamous epithelium have yet to be elucidated. Methods: In this study, three‐dimensional human tissue equivalents are exposed to varying concentrations of tooth‐whitening agents for increasing time periods. Tissue alterations are investigated in terms of morphology, proliferation, apoptosis, and protein expression. Results: All whitening agents tested altered tissue morphology, induced proliferation of basal keratinocytes, and caused apoptosis of cells in all epithelial strata. In addition, whitening agents induced alterations in the expression of cytokines that are linked to inflammation. Conclusions: These results suggest that whitening agents may induce similar changes in vivo and that these products should be used for limited periods of time or under the supervision of a dental professional.     

Adhesion of viridans group streptococci to sialic acid‐, galactose‐ and N‐acetylgalactosamine‐containing receptors

The binding of 10 viridans group streptococci to sialic acid‐, galactose (Gal)‐ and N‐acetylgalactosamine (GalNAc)‐containing receptors was defined by analysis of the interactions between these bacteria and structurally defined glycoconjugates, host cells and other streptococci. All interactions with sialic acid‐containing receptors were Ca²⁺‐independent as they were not affected by ethyleneglycoltetraacetic acid (EGTA), whereas all interactions with Gal‐ and GalNAc‐containing receptors were Ca²⁺‐dependent. Recognition of sialic acid‐, Gal‐ and GalNAc‐containing receptors varied widely among the strains examined, in a manner consistent with the association of each of the three lectin‐like activities with a different bacterial cell surface component.     

Implant‐abutment connection as contributing factor to peri‐implant diseases

Dental implant–supported prostheses are an established treatment modality for the functional and esthetic rehabilitation of partial and/or complete edentulous patients. One of the most essential factors for successful treatment outcomes stems from preservation of the peri‐implant bone. Early peri‐implant crestal bone loss has been a common observation, coincides with the time period where most treatment manipulations occur and has been considered as a complex multifactorial event. Microbial leakage at the implant‐abutment interface has been associated with inflammatory reactions that may jeopardize peri‐implant crestal bone stability. Prevention of microbial leakage at the implant‐abutment interface is a major challenge in the construction of two‐piece implant systems. Changes in the implant‐abutment complex design achieved reduction in the magnitude of microbial leakage and/or separation of the implant‐abutment interface from the osseous surface. However, it is still unclear if microbial leakage at the implant‐abutment interface plays a role beyond the initial crestal bone remodeling, namely on the development of peri‐implantitis. Therefore, the aim of this review is to analyze the knowledge available on the integrity of different types of implant‐abutment connections and their potential role on the development of peri‐implant crestal bone loss and peri‐implant diseases.     

Effect of a 12‐methacryloyloxy‐dodecyl‐pyridinium‐bromide–containing adhesive with different post types on the long‐term bond strength to dentin

The use of matrix metalloproteinase (MMPs) inhibitors, such as 12‐methacryloyloxy‐dodecyl‐pyridinium‐bromide (MDPB), might improve the adhesion of glass‐fiber (GF) and polyfiber (PF) posts to root dentine. This study assessed the effect of an MDPB‐containing adhesive on the long‐term bond strength of GF or PF posts to bovine dentine. Bovine endodontically treated roots were randomly divided into six groups, according to the post type and adhesive system used, as follows: GF serrated post + MDBP‐free adhesive; GF serrated post + MDPB‐containing adhesive; GF smooth post + MDBP‐free adhesive; GF smooth post + MDPB‐containing adhesive; PF post + MDBP‐free adhesive; PF post + MDPB‐containing adhesive. Specimens were stored in water for 6 months, thermocycled (500 cycles wk^?1), and submitted to the pull‐out test and failure pattern analysis. The cement–dentin interface was evaluated using scanning electron microscopy. The pull‐out data were analyzed using anova and Tukey's test (α = 0.05). No significant interaction between the type of post and the adhesive system was found. Polyfiber posts showed lower bond strength than GF posts, whether serrated or smooth, and the bond strength of the serrated and smooth GF posts was not significantly different. Adhesive failures were predominant in all groups. The type of retainer influenced the bond strength, and MDPB‐containing adhesive did not improve the long‐term bond strength of posts to dentine.     

A controlled study of dental erosion in 2‐ to 4‐year‐old twins

International Journal of Paediatric Dentistry 2010; 20: 400–409 Background. Dental erosion (DE) in children is a significant oral health issue and has become a focus for research in clinical paediatric dentistry. Aim. This study investigated DE in the primary dentition of 2‐ to 4‐year‐old twin and singleton children with regard to the genetic, medical and dietary factors associated with the condition. Design. The 128 subjects consisted of 88 twin children (31 monozygous, 50 dizygous, 7 unknown zygosity) and singletons (n = 40) aged 2–4 years. Medical, dental, and dietary histories were obtained. The children were examined for DE using a modified index. Results. The prevalence of DE by subject affected was 77% in monozygotic twins (MZ), 74% in dizygotic twins (DZ), and 75% in singleton controls (P > 0.1). Of the teeth scored, 12% had mild, 10% moderate, and 1% severe lesions, and DE was more severe in the older age group (P < 0.05). Concordance rates for erosion lesions in MZ and DZ co‐twins were not statistically significant. Conclusions. The prevalence of DE and the concordance of erosion lesions were similar between MZ and DZ twins and singleton children, suggesting that the contribution of genetic factors to DE is negligible.     

Long‐Term Function of Single‐Implant Restorations: A 17‐ to 19‐Year Follow‐Up Study on Implant Infraposition Related to the Shape of the Face and Patients' Satisfaction

Background: Various levels of infraposition of single‐implant restorations have been observed in long‐term follow‐up studies, but little knowledge is available on the biological mechanism behind this pattern. Purpose: The primary aim of this study is to report the frequency and severeness of implant infraposition in the anterior single‐implant application after 17 to 19 years in function and, secondly, to try to relate these observations to anatomical appearance of the shape of the face of the patient. Materials and Methods: The present study comprised of 57 patients who were provided with 65 CeraOne? single‐tooth restorations (Nobel Biocare AB, Gothenburg, Sweden) between 1989 and 1991. Altogether 46 of these patients were treated with single implants in the anterior region. Besides clinical and radiographic data, clinical photographs, study casts, and patient's assessment of the long‐term aesthetic result (visual analog scale) was collected at the termination of the present study. The degree of implant crown infraposition was related to assessed facial shape and to patient and clinical assessment of the aesthetic result by means of Pearson's correlation test. To increase the numbers of patients, another group of 25 patients presented in another similar study were pooled with the present material for prevalence calculations. Results: Altogether 47 patients showed up for the final examination after an average of 18 years (82%). Two implants failed (18 years cumulative survival rates [CSR]– 96.8%) and eight original single‐crown restorations were replaced (CSR 83.8%). Three of the replaced crowns were replaced because of infraposition of the crowns. About 40% of the patients showed signs of infraposition, similar in younger and older age groups, but more frequently observed in female patients at termination of the study (p < 0.05). There was a weak trend indicating an association between “long‐face” appearance and infraposition of the crown restoration (p > 0.05), and patients were more satisfied with the aesthetic clinical result than the participating clinicians (p < 0.05). Conclusion: Single‐implant restorations in the anterior upper jaw may present small degrees of infraposition in long‐term perspectives. Female patients seem to be at a higher risk of infraposition (p < 0.05), but no clear relationship between age at implant placement or facial shape and degree of infraposition was possible to establish (p > 0.05). Patients were more satisfied with the aesthetic result, as compared with the clinicians (p < 0.05), and patients seemed to pay less attention to the degree of infraposition in their aesthetic assessments, as compared with most of the clinicians.     

Clinical approaches to treat peri‐implant mucositis and peri‐implantitis

Therapies proposed for the treatment of peri‐implant diseases are primarily based on the evidence available from treating periodontitis. The primary objective is elimination of the biofilm from the implant surface, and nonsurgical therapy is a commonly used treatment. A number of adjunctive therapies have been introduced to overcome accessibility problems or difficulties with decontamination of implant surfaces as a result of specific surface characteristics. It is now accepted that following successful decontamination, clinicians can attempt to regenerate the bone that was lost as a result of infection. The ultimate goal is re‐osseointegration, and a number of regenerative techniques have been introduced. By reviewing the existing evidence, it seems that peri‐implant mucositis is reversible when appropriately treated. Additionally, a combined therapy (mechanical therapy with local antimicrobials as adjuncts) can serve as an alternative to surgical intervention when treating peri‐implantits in cases not suitable for surgery. Surgical therapy is an effective method for treating peri‐implantitis, and various degrees of success of the use of regenerative procedures have been reported, regardless of whether or not radiographic evidence of defect fill has been achieved. Finally, no matter which therapy is employed, a prerequisite for the long‐term stability of treatment results obtained is the ability of the patient to maintain good oral hygiene.     

High fear of intra‐oral injections: prevalence and relationship to dental fear and dental avoidance among 10‐ to 16‐yr‐old children

The present study aimed to: (i) estimate the prevalence of self‐reported high fear of intra‐oral injections, high blood‐injury fear, and injection fear; (ii) explore the overlap between high fear of intra‐oral injections and high fear of dental treatment; and (iii) evaluate the possible consequence of high fear of intra‐oral injections in terms of avoidance of dental care. The sample included 1,441 subjects, 10‐ to 16‐yr of age, attending elementary schools in a county of Norway. Data were collected using questionnaires that were completed in classrooms. The survey instruments used were the Intra‐Oral Injection Fear‐scale, the Children's Fear Survey Schedule‐Dental Subscale, the Injection Phobia scale for children, and the Mutilation Questionnaire for children. In total, 13.9% of the children reported high intra‐oral injection fear. A strong association was found between fear of intra‐oral injections and dental fear. When an intra‐oral injection was needed, 10.6% would avoid dental treatment. In multiple regression analysis, high intra‐oral injection fear was found to be associated with avoidance of dental treatment (OR = 6.52; 95% CI: 3.99–10.67). It was concluded that high fear of intra‐oral injections was prevalent and might lead to avoidance of necessary dental treatment. Hence, intra‐oral injection fear should be addressed before treatment of dental fear.