The Role of the Immune Response in Chronic Marginal and Apical Periodontitis

The immune response is a complex, dynamic and strongly individual biologic network that plays an essential role in the pathogenesis of chronic apical and marginal periodontitis. Recent research in the field of periodontology has indicated that the major determinant of susceptibility to disease is the nature of the immunoinflammatory response as marginal periodontal tissue damage is thought to be primarily mediated by the host reaction. Whether the same rules apply for the development of apical periodontitis, however, remains largely unexplored. This review aims to draw parallels between the pathogenesis of chronic periodontitis of endodontic and marginal origin, outline the evidence for the destructive role of immune response in chronic marginal periodontitis and raise questions about its role in chronic apical periodontitis. It would be worthy to further explore the impact of the immune system on the characteristics and progress of these diseases and transfer some of the scientific models from the field of periodontology to the field of endodontics. Research in this area could lead to a more comprehensive understanding of the dynamics of apical and marginal periodontitis and lay the foundation of new personalized treatment strategies.

APPLICATION OF 3D DIGITAL SCANNING AND CAD/CAM SYSTEMS FOR ZIRCONIA INDIRECT RESTORATIONS

Object: To study the CAD/CAM systems’ possibilities for manufacturing Zirconia indirect restorations for restoring vital, vastly devastated teeth. Material and methods: Five patients with vital, heavily destroyed molars were included in the clinical study. The teeth were prepared according to requirements for Zirconia restorations. The impressions were taken with 3D intraoral scanner. The acquired data is transmitted electronically for designing the future restoration by the CAD software. After designing, the restoration is milled by the CAM module and sintered, according to a specially projected programme in accordance with the manufacturing demands. After clinical check-up, the restorations are glazed, air-blasted and cemented. Results: Setting up an individual protocol for working with CAD/CAM systems for restoring vital, severely devastated teeth with Zirconia indirect restorations. A research is made on 3D digital scanning, occlusal and proximal modeling, virtual articulation, analyzing the incline of the cavity walls, the thickness of the restoration and the possibilities for restoring the anatomy of the tooth according to patient’s individual characteristics of the teeth’s arch. Conclusion: The scanning and design process should be evaluated with the same quality control as when using traditional methods. The CAD software requires excellent preparation of the tooth cavity and digital scanning. This is the reason why these systems require a thorough understanding of CAD/CAM calibration and parameters of the product to be clinically acceptable. Once understood, CAD/CAM dentistry can create detailed and accurate restorations that function and perform with great success and longevity

Clinical Effect of Dental Adhesive on Marginal Integrity in Class I And Class II Resin-Composite Restorations

BACKGROUND: Dental adhesives are believed to influence marginal adaptation and marginal discoloration when used under posterior resin-based composite restorations. Studies on the latest adhesive systems reveal that the group of the three-step etch-and-rinse adhesive (3-E&RA) and the one-step self-etch adhesive (1-SEA) have entirely different bonding mechanisms, as well as different bond strength and resistance to chemical, thermal and mechanical factors. STUDY OBJECTIVES: A hypothesis that a 1-SEA would result in greater enamel marginal discoloration and poorer marginal adaptation than a 3-E&RA was tested. MATERIAL AND METHODS: One hundred restorations were placed with a 1-SEA and 100 restorations with a 3-E&RA. Teeth were restored with Filtek Supreme nanofilled resin-composite and were evaluated for marginal adaptation and marginal discoloration at baseline, and 6 months, 12 months, and 36 months postoperatively. RESULTS: The statistical analysis revealed significant differences in marginal integrity between test groups. The 1-SEA resulted in greater enamel marginal discoloration and poorer marginal adaptation than the 3-E&RA at any recall time. CONCLUSIONS: Marginal adaptation and marginal discoloration depend on the type of dentin adhesive used. The restorations with Filtek Supreme and Scotchbond MP are better than the restorations with Adper Prompt L-Pop with regard to the marginal adaptation and marginal discoloration at 6-, 12- and 36-month evaluations

Clinical Impact of Dental Adhesives on Postoperative Sensitivity in Class I and Class II Resin-Composite Restorations

BACKGROUND: Self-etch adhesives are believed to prevent postoperative sensitivity when used under posterior resin-based composite restorations. STUDY OBJECTIVE: A hypothesis that a one-step self-etch adhesive (1-SEA) would result in less postoperative sensitivity than a three-step etch-and-rinse adhesive (3-E&RA) was tested. PATIENTS AND METHODS: One hundred restorations were placed with a 1-SEA and 100 restorations with a 3-E&RA. Teeth were restored with Filtek Supreme nanofilled resin-composite and were evaluated for sensitivity to cold and masticatory forces at baseline, 7 days, 14 days, 30 days, and 6 months postoperatively. Vitality test scores of the teeth were recorded at the same periods. RESULTS: The evaluation of cold sensitivity intensity (VAS score) for all observation periods in both restoration groups did not reveal any statistical significance. The differences in the response time to cold stimulation (0 - 15 sec) for the restorations made with a 1-SEA and those made with a separate etch step are statistically insignificant. There are no significant differences in the vitality of the restored teeth at intra- or inter-group comparison. The statistical analysis revealed significant differences in postoperative sensitivity to masticatory forces at postoperative day 14 and day 30 in the 3-E&RA group. CONCLUSIONS: Postoperative sensitivity depends on the type of dentin adhesive used. More intensive complaints of postoperative sensitivity were recorded under masticatory forces at postoperative day 14 and day 30 in 3-E&RA in comparison with 1-SEA

Clinical Evaluation of CAD/CAM Indirect Zirconia Restorations of Severely Destroyed Vital Teeth in the Posterior Area – Early Clinical Results

Background: Dental applications of CAD/CAM concept have been available for almost 30 years. They have allowed dentists to work with novel materials with better properties. One of these materials is zirconia ceramic

Quality of Endodontic Treatment and Prevalence of Apical Radiolucencies in a Bulgarian Subpopulation: a CBCT Analysis

Introduction: The advent of Cone Beam Computed Tomography (CBCT) in endodontics has enhanced the diagnosis of periapical radiolucencies and the assessment of endodontically treated teeth. Aim: The purpose of this study was to assess the prevalence of periapical radiolucencies in a Bulgarian subpopulation and the quality of previous endodontic treatment using CBCT scans.Materials and methods: This study included 2795 roots from 160 Large FOV CBCT which were evaluated by two independent examiners using two scoring systems: CBCT-PAI and PESS. Results: The inter-examiner agreement spanned from strong to almost perfect (0.892 and 0.983). The prevalence of periapical lesions according to the two scoring systems was 23.1% and 12.9 %, respectively. The prevalence of endodontically treated teeth was high (34.1%). Sixty-five percent of them presented with signs of periapical radiolucencies, while only 1.4% of all non-treated roots had a periapical lesion. A significant association between periapical disease, poor quality of the root canal filling and inadequate coronal seal was found (p<0.001). Conclusions: The prevalence of periapical disease in endodontically-treated teeth in the Bulgarian subpopulation was high. Poor qual-ity of the root canal filling and inadequate coronal seal were assessed as prognostic determinants of treatment failure. CBCT techniques can augment conventional diagnostic techniques in the field of endodontics.&nbsp

NOVEL METHODS FOR THE ASSESSMENT OF CRACK PROPAGATION IN ENDODONTICALLY TREATED TEETH

Background: Vertical root fractures (VRF) can be defined as either complete or incomplete fractures that occur predominantly in endodontically treated teeth (ETT). The clinical symptoms and conventional radiographic techniques are not always accurate, which can lead to diagnostic errors. This motivated us to seek new, better techniques that can improve the prognosis and treatment of ETT with vertical fractures. Objective: The aim of this study was to investigate the potential of three novel techniques: Cone Beam Computed Tomography (CBCT), Optical Computed Tomography (OCT) and 3D Profilometry for the visualization and assessment of VRF. Methods: The study involved intact human premolars, extracted for orthodontic or periodontal reasons. The teeth were then endodontically treated and restored with prefabricated metal posts. No additional preparation of the coronal hard dental tissues was performed, apart from the access cavity. After thermocycling, their fracture resistance was evaluated in a standard testing machine. The resulted vertical fractures and crack propagation were evaluated using CBCT, OCT and 3D Profilometry. Results: The CBCT provided visualization of the tooth in three planes: axial, coronal and sagittal. Root fractures were observed at the coronal and middle 1/3 of the root. The OCT provided highly-detailed, biomicroscopic cross-sectional images of the mesial and distal root surfaces. The images, obtained with 3D Profilometry showed the surface topography and provided precise information about the width and depth of the VRF. Conclusion: All of the techniques used in this study proved to be highly informative, non-invasive and non-contact methods, suitable for the evaluation of VRF