Aesthetic rehabilitation in a young patient using a minimally invasive approach. A multidisciplinary case report.

BACKGROUND: Optimal integration and long-term stability of oral rehabilitations require correct diagnostic approach, appropriate pre-prosthetic treatments and accurate therapeutic protocols. Technology provides devices to optimise therapeutic results, according to biologic constraints and aesthetic parameters. CASE REPORT: The present report describes a multidisciplinary management in a young patient affected by lateral incisor agenesis, including pre-prosthetic orthodontic treatment and restorative and implant-supported prosthetic rehabilitation. Minimally invasive clinical procedures with veneer restorations and flapless implant placement, followed by immediate prosthesis delivery, are carried out. Tridimensional diagnostic data and dedicated software were used for treatment planning, allowing to achieve optimal results.

Conservative approach for the management of congenital bilateral agenesis of permanent mandibular incisors: case report and literature review.

BACKGROUND: Agenesis of mandibular incisors can lead to compromised dental and facial aesthetics and therefore requires appropriate treatment. When retained primary incisors are associated to this condition, a medium-term restoration may be provided before any definitive treatment to provide aesthetic relief to the young patient. CASE REPORT: The aim of this paper is to discuss the aesthetic management of a case with bilateral congenital agenesis of permanent incisors and retained primary incisors, which were successfully treated with direct composite restorations. CONCLUSION: This appears a viable technique that restores function and aesthetics with a very conservative approach.

Influence of a repeated preheating procedure on mechanical properties of three resin composites.

The aim of this study was to assess the flexural strength, flexural elastic modulus and Vickers microhardness of three resin composites prepared at room temperature or cured after one or repeated preheating cycles to a temperature of 39°C. Three resin composites were evaluated: Enamel Plus HFO (Micerium), Opallis (FGM), and Ceram X Duo (Dentsply DeTrey). For each trial, one group of specimens of each material was fabricated under ambient laboratory conditions, whereas in the other groups, the composites were cured after 1, 10, 20, 30, or 40 preheating cycles to a temperature of 39°C in a preheating device. Ten rectangular prismatic specimens (25 × 2 × 2 mm) were prepared for each group (N=180; n=10) and subjected to a three-point bending test for flexural strength and flexural modulus evaluation. Vickers microhardness was assessed on 10 cylindrical specimens from each group (N=180; n=10). Statistical analysis showed that, regardless of the material, the number of heating cycles was not a significant factor and was unable to influence the three mechanical properties tested. However, a significant main effect of the employed material on the marginal means of the three dependent variables was detected.

Effect of repeated preheating cycles on flexural strength of resin composites.

The aim of this study was to assess the flexural strengths of three resin composites prepared at room temperature or cured after 20 or 40 cycles of preheating to a temperature of 45°C. Three resin composites were evaluated: Enamel Plus HFO (Micerium) (HFO), Enamel Plus HRi (Micerium) (HRi), Opallis + (FGM) (OPA). One group of specimens for each composite was fabricated under ambient laboratory conditions, whereas in the other groups, the composites were cured after 20 or 40 preheating cycles to a temperature of 45°C in a preheating device. Ten specimens were prepared for each group. A three-point bending test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed with a two-way analysis of variance (ANOVA) test and a Games-Howell test (α = 0.05). The two-way ANOVA showed that both the material and the number of heating cycles were significant factors, able to influence the flexural strength values (p<0.05). However, there was not a statistically significant interaction (p>0.05). For all three composites flexural strengths were not affected after 20 preheating cycles in comparison with the control groups (0 preheating cycles) but were, however, significantly decreased when 40 prewarming cycles were conducted. The HRi and OPA groups had the highest flexural strengths, with no statistically significant differences among them. HFO presented significantly lower flexural strengths in comparison with HRi.

Conservative restorations of endodontically compromised anterior teeth in paediatric patients: physical and mechanical considerations.

AIM: Objective of this in vitro study was to evaluate the influence of fiber post placement on fracture resistance of pulpless anterior teeth restored with standardised Class III and Class IV resin composite fillings. MATERIALS AND METHODS: One hundred and five human maxillary central incisors were selected and randomly divided into 7 (n=15) experimental groups (endodontic therapy/ endodontic therapy and one Class III resin composite filling/ endodontic therapy and one Class IV resin composite filling/ endodontic therapy and two Class III resin composite fillings/ endodontic therapy, fiber post and one Class III resin composite filling/ endodontic therapy, fiber post and one Class IV resin composite filling/ endodontic therapy, fiber post and two Class III resin composite fillings). Specimens underwent fracture strength test. Means (N) were calculated and data were analysed using 1-way ANOVA and Tukey multiple comparisons tests (p=0.05). RESULTS: Concerning teeth with two Class III, fiber post placement significantly increased fracture strength values from 603.59 to 864.24 N. Specimens restored with one Class III (795.21 N without post, 936.68 N with post) showed higher fracture strength values if compared with specimens with two Class III, with significant differences just concerning specimens without a fiber post. Fracture strength was not significantly influenced by fiber post placement in Class IV groups (720.71 N without post, 799.69 N with post). CONCLUSION: Data suggest that fiber post placement may significantly improve anterior teeth fracture strength when at least two Class III composite fillings are associated to the endodontic treatment. No significant effect of fiber post placement could be recorded when just one Class III or one Class IV composite filling were present.

Histomorphologic alterations of human enamel after repeated applications of a bleaching agent.

The objective of the study was to analyse the histomorphology of enamel after repeated applications of a professional bleaching regimen. Enamel specimens were obtained from buccal surfaces of 20 extracted human incisors. Two specimens were obtained for each tooth. Half of each tooth was maintained in distilled water and served as control; the other part was treated with a 38 percent hydrogen peroxide professional bleaching agent. The treated specimens were divided in four groups: in group 1, the professional bleaching protocol suggested by the manufacturer was applied once; in group 2, the same protocol was repeated twice; in group 3, three times; in group 4, four times. Between bleaching applications and before SEM evaluation, enamel specimens were maintained in artificial saliva for 1 week. Enamel specimens for each group were submitted to a qualitative scanning electron microscopy (SEM) analysis (200X, 500X, 1000X, 3000X), comparing the treated specimens with the related control enamel. Results of the SEM analysis showed no relevant alteration on the enamel surfaces, when the bleaching protocol was applied once or twice. However, significant changes of enamel surface morphology were SEM observed in groups 3 and 4, suggesting a predominance of depressions when bleaching procedure was repeated three or four times. From the results of this in vitro study, it is possible to state that bleaching procedures should not be carried out indiscriminately. SEM analysis showed important alterations of the prismatic structure of the enamel when the bleaching protocol was applied three and four times.

The cytotoxic effects of resin-based sealers on dental pulp stem cells.

AIM: To evaluate the effect of four current resin-based adhesives on expanded ex vivo human dental pulp mesenchymal stem cells (DP-MSCs). METHODOLOGY: Dental pulp mesenchymal stem cells were derived from dental pulps of ten donors. After in vitro isolation, dental pulp stem cells were analysed using flow cytometry. The immunophenotype of DP-MSCs disclosed the homogeneous expression of the mesenchymal-related antigens CD29, CD44, CD73, CD90, CD105, CD166. DP-MSCs were exposed to four different commercially available bonding systems (CMF Bond, Prime&Bond NT, Clearfil S(3) Bond, XP Bond), and after 24, 48 and 72 h of incubation the morphological features and the cell growth were analysed. Moreover, the cell viability was evaluated at the same times by MTT assay. Data were statistically analysed using a two-way anova and Holm-Sidak method (alpha set at 0.05). RESULTS: Significant differences were observed between the four groups when comparing DP-MSCs appearance. DP-MSCs survived and proliferated without inhibition in the presence of CMF Bond adhesive. On the contrary, microscopic evaluation of the other three groups revealed extensive cytotoxic effects from the dentine bonding agents. The MTT assay revealed no statistically significant differences in cell viability after 72 h between the control group and CMF Bond group. All the other experimental groups had statistically lower optical density values. CONCLUSIONS: CMF Bond adhesive allowed human dental pulp stem cells to survive and proliferate. All of the other dentine bonding agents had extensive cytotoxic effects.

Bond strengths of three types of fibre-reinforced post systems in various regions of root canals.

AIM: To evaluate the bond strengths of three adhesive/resin cement/fibre post systems to coronal, middle and apical thirds of post space dentine. METHODOLOGY: Three types of glass-fibre post systems were selected for the study. Saremco Post Non-stop Fibre (Saremco), FRC Postec Plus (Ivoclar Vivadent) and Anatomical Post (Dentalica) were luted in prepared root canals using adhesive system and resin cement provided by the respective manufacturer. The luting agent was placed into the root canal using a specific syringe with needle. A push-out test was performed on sections from the apical, middle and coronal parts of each specimen to measure bond strength. All fractured specimens were observed using a stereomicroscope to identify the modes of failure. RESULTS: Bond strength values were significantly affected both by the post-adhesive-cement system used and by root region (P < 0.05). Additionally, there was no significant interaction between the post system and region of canal factors (P > 0.05). The highest bond strength values were found in the coronal third for all experimental groups. The middle and apical thirds exhibited similar bond strengths with no statistically significant differences amongst them. Saremco and Precision post systems had the highest retentive strengths, whilst the Ivoclar post system had the lowest values. Microscopic analysis of the specimens revealed a prevalence of post-cement and mixed failures. CONCLUSIONS: Type of post-adhesive-cement system and root position had a significant effect on fibre post retention. The coronal region of the canals was characterized by significantly higher bond strengths.

Caries-risk assessment: the role of salivary tests.

Although the incidence of caries has diminished dramatically over the past 3 decades, small groups of subjects remain highly susceptible and do not respond to conventional preventive programs. An accurate individual caries-risk assessment allows to identify the etiological factors responsible for the disease and design a rational approach to treatment, addressed to the specific needs of the patients. The use of appropriate caries-risk prediction models, which include the use of simple chairside caries-susceptibility salivary tests, is the most suitable and modern approach to the problem. A review of the literature on salivary tests, at present available, able to identify the factors contributing to caries susceptibility, is presented. Each test is accurately described, with regard both to its procedure and the interpretation of its results:

Some tools for the identification of high caries risk individuals. A review.

As a consequence of the polarisation of dental caries, which occurred over the last 3 decades in industrialised countries, the usefulness of risk assessment, both for individuals and for groups of subjects, became evident. At individual level, the early identification of high and medium caries-risk subjects allows to plan specific preventive measures for each subject's needs, based on the risk grade and the causally-directed diagnosis. At population level, risk assessment helps to increase the efficiency and to reduce the costs of caries preventive programmes. In this study, a review of caries-risk indicators is proposed: these indicators, collected through the analysis of relevant background data, clinical examination and salivary tests are indispensable to achieve a correct caries-risk assessment. A review of the studies on the attempts to produce prediction models for caries-risk assessment is presented: in view of the multifactorial nature of caries etiology and the complexity of the prediction of individual caries-risk, a multivariate approach is necessary. Finally, some suggestions on the clinical usefulness and on indications of caries-risk determination are given.