Clinical Assessment of Endodontically Treated Teeth, Restored with or without Radicular Posts.

BACKGROUND: The reduced fracture resistance in endodontically treated teeth requires the use of radicular posts, with their advantages and disadvantages. AIM: To evaluate the clinical performance of teeth restored with or without radicular posts at 6 and 12 months. MATERIALS AND METHODS: The study included 22 patients who received endodontic therapy on premolars with a loss of one or two proximal walls. The premolars were divided into groups according to the restoration method: metal post group (MP), fiber post group (FP), and no post group (NP). For the NP group, a dentinal core of fiber-reinforced composite was used. The McNemar test, marginal homogeneity test and Kruskal-Wallis test were used in the statistical analysis. At the 6 and 12 month recall, both the direct composite restorations and the integrity of the post systems were assessed. RESULTS: At 6-month recall assessment, there was no statistically significant difference in the categories of 'appropriate colour', 'secondary caries' and 'obturation integrity'. That was not the case with 'marginal discoloration', 'marginal adaptation', 'proximal contact' and 'surface smoothness'. The recall at 12 months showed a continuation of this tendency, with significant decrease in the category of 'adequate colour'. Assessment of post longevity at the two recalls did not show any significant changes. The teeth restored without a post showed survival rates comparable to that of teeth restored with a post for the 12-month period of observation. CONCLUSIONS: There were no failures of the different posts used. The observed changes were attributed to the progressive deterioration of the composite restorations.

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 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.

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.

Effect of ageing and endodontic treatment on the thermal stability of human dentin.

BACKGROUND: Human dentin is a highly calcified tissue of mesenchymal origin with a heterogeneous structure. Its morphology is constantly remodelled throughout the life span of the tooth, as well as under the influence of external stimuli. OBJECTIVE: The aim of the present study was to obtain information about the thermal changes in the crown and root dentin specimens of vital and devitalized teeth. METHODS: The investigated samples were divided into 6 groups, depending on the patients' age and dentin location (crown, root). An additional group of endodontically treated teeth was created. The methods of choice were were combined thermal analysis (DTA-TG(DTG)-MS and gas chromatography-mass spectrometry. RESULTS: After heating up to 1200 °C, endo- and exothermal effects were observed. The effects' dynamic was the same for all samples. The differences were in the samples' weight after the experiment, with root dentin showing the greatest mass loss percentage. CONCLUSIONS: The observed mass loss differences could be attributed to the presence of impurities in the dentin, as well as alterations in the collagen matrix. Ageing and endodontic treatment could catalyse the accumulation of such changes and affect the microstructure of the mineralized tissue.

Clinical evaluation of restorations with self-etch adhesive and nanofilled composite in class I and class II cavities.

INTRODUCTION: In the era of adhesive restorative dentistry the principles of conventional cavity preparation have acquired a new meaning. The emphasis is shifted from "widening for preventive purposes" and preparation of macro-mechanical retention to "consciously limited" preparation. The clinical and biological durability of restorations depends on the adhesive bond and the quality of the composite material. OBJECTIVE: The aim of the study was to conduct a clinical evaluation of restorations with a self-etch single-step adhesive and nanofilled composite in class I and class II cavities over a period of 15 months. PATIENTS AND METHODS: The clinical trial involved 34 patient (volunteers) who received 76 posterior restorations of medium and deep cavities with the self-etch adhesive Adper Prompt L-Pop and nanofilled composite Filtek Supreme (3MESPE Dental products USA). All restorations were evaluated by the modified Ryge and Cvar criteria at 6- and 15-month intervals. RESULTS: Loss of restorations with a self-etch single-step adhesive and nanofilled composite at 6 months and 15 months was 0% and 6.7%, respectively. The evaluation of discolouration in the restorations at 6 months revealed no significant changes (P > 0.05, u = 1.72). There was certain deterioration in the colour at 15 months (P < 0.05, u = 2.96). Statistically significant changes in the marginal discolouration were observed at 6 months (P < 0.05, u = 2.79) in comparison with the initial scores. During the 15-month follow-up the discolouration on the margins of the restorations was statistically nonsignificant compared to the 6-month follow-up (P > 0.05, u = 0.36). There were no C (Charlie) scores recorded during the 15-month follow-up study within the continuing observation. CONCLUSION: The restorations with nanofilled composite and self-etch single-step adhesive fulfill the requirements for clinical use in posterior restorations.

Evaluation of the accuracy of electronic apex locators Dentaport ZX and Ray Pex 4 under clinical conditions.

AIM: The aim of the present study was to compare the accuracy of working endodontic length determination by Dentaport ZX and Ray Pex 4 under clinical conditions. MATERIAL AND METHODS: Clinical comparative evaluation of the accuracy of two electronic apex locators, Dentaport ZX and Ray-Pex 4, was carried out in 80 single-rooted teeth with vital pulp tissue planned for extraction as part of the dental treatment and after patient consent had been obtained. The normal procedure was followed, which included anesthesia, a standard endodontic access cavity, pulp removal and irrigation of the root canal with 5.25% NaOCl. The working length was estimated with Dentaport ZX for half of the selected teeth and with Ray-Pex 4 for the other half. K-files #15 were cemented at the measured working length and the teeth were extracted. The apical foramen was examined with a stereomicroscope under x15 magnification. The micrometric system of the microscope allowed precise measurement of distances. RESULTS: The comparison of the estimated working length with the actual length revealed that Dentaport ZX localized the apical foramen in 95% of the cases and the Ray Pex 4 in 92.5% with a clinically acceptable accuracy of +/- 0.5 mm. Dentaport ZX detected the foramen in 97.5% and Ray Pex 4 in 95% of the cases with an accuracy of +/- 1 mm. There was no statistically significant difference between the accuracy of the two electronic apex locators in locating the apical foramen (p < 0.05).

Early results of the use of ProRoot MT and Titan cement for furcation perforation repair--a comparative experimental study.

UNLABELLED: The aim of the present experimental study was to follow up the connective tissue response after using ProRoot MTA and Titan cement to repair furcation perforations in dogs. MATERIAL AND METHODS: Four animals aged 12 to 18 months were used in the study. Perforation defects were created in the center of the pulp chamber of mandibular premolars P2, P3 and P4, right and left. The defects on the left side were repaired with ProRoot MTA, and those on the right side--with Titan cement in all dogs. After 30 days bone fragments with teeth included were fixed in formalin and decalcified in 50% formic acid. Serial sections of 10 microm thickness were prepared, stained with hematoxylin and eosin and studied under light microscopy. RESULTS: The connective tissue response in the Titan cement repaired teeth was a fibrous capsule in contact with the material, with single or aggregated lymphocytes seen in the vicinity. The response to ProRoot MTA was similar, but the fibrous capsule was thinner and without any aggregation of lymphocytes. CONCLUSIONS: The connective tissue response was similar for both tested materials. The tissues tolerated both of them well; it formed a fibrous capsule, which is indicative of the start of a healing process.

Residual monomer in a composite resin after light-curing with different sources, light intensities and spectra of radiation.

The purpose of this study was to investigate the amount of residual monomer in a composite resin after light-curing with different sources, light intensities and spectra of radiation. The resin specimens (4 mm in diameter; 2 mm thick) (n=5) were inserted in Plexglass matrixes and light-cured with a halogen lamp, LED and PAC units for 40, 40 and 5 s, respectively. The polymerized specimens were ground and 25 mg of each specimen were immersed in 8 mL 96% ethanol for 24 h to extract the residual monomer. The amount of residual monomer was determined by the standard straight line method. The light spectrum of the different LCUs was shot and processed through researches of the absorbation of the standard solutions at a level of lambda=275 nm and their extracts. Data were analyzed statistically by variational dispersion analysis and Tukey-Kramer test at 5% significance level. It was observed that, the halogen lamp produced the smallest amount of monomer under sufficient light intensity. The spectrum of light radiation of PAC was within the limits of 450- 490 nm and was of extremely high intensity. This imposes the use of short-limited light impulses, but also might lead to deterioration quality of polymerization. The LED unit had the best spectral radiation. An increase of light intensity was proved necessary.

Factors for post-operative sensitivity in dental caries treatment according to practicing dentists--application of network analysis.

INTRODUCTION: The postoperative tooth sensitivity is a dental caries post-treatment complication of unknown origin. The variety of clinical symptoms of this condition, the contributing factors and their interactions may be presented by means of network analysis. AIM: The aim of the present study was to apply network analysis to present the relationships between factors contributing to post-operative sensitivity according to practicing dentists. PATIENTS AND METHODS: We carried out an anonymous questionnaire survey of 213 dentists to assess their experience with diagnosed post-operative sensitivity. The duration and kind of the condition was studied to find its correlation with the type of restorative material, the location of carious defect, and the depth of carious defect. The respondents gave their opinions about the probable causes of post-operative sensitivity. Multiple answers to one question were allowed. Data was processed with the help of SPSS and UciNet. RESULTS: 806 ties between factors for post-operative sensitivity were investigated. Their absolute size (C) ranged from -16 to +175. The most significant relationships, defined at C > or = 0.3, comprised 20% of all ties. CONCLUSIONS: The following relationships between factors associated with post-operative sensitivity were found: cold-induced pain of up to 1 week duration after treatment of caries profunda acuta and placement of an amalgam restoration; pressure-induced pain of up to 3 weeks duration after treatment of caries profunda chronica, class II cavities and placement of a composite resin restoration. The visualized structures of interrelated factors represented only the clinical experience of the questioned dentists. Their confirmation in clinical practice is a matter of future investigations.

A study of post-operative sensitivity in class I and class II restorations with self-etching adhesive and nanofilled composite.

AIM: The aim of the study was to determine the type, intensity and duration of post operative sensitivity (POS) in class I and II cavity restorations with self-etching adhesive and nanofilled composite. PATIENTS AND METHODS: The clinical study included 34 patients, who received a total of 76 restorations by undergraduate dental students. The restorations were made in medium and deep cavities. Self-etching adhesive Adper Promp L-Pop and nanocomposite Filtek Supreme (3MESPE Dental products USA) were placed. The type, the magnitude and the duration of postoperative sensitivity were examined on days 1, 3, 5, 7, 14 and 30. Intensity of sensitivity perceptions were recorded on a visual analogue scale using the method of self-observation. Parametric and non-parametric analyses were employed at a significance level of P < 0.05. RESULTS: Pressure-dependent POS was present in most of the cases (15.78% +/- 4.209), followed by discomfort (9.21% +/- 3.340) and pressure- and cold-induced pain (1.33% +/- 1.147). A statistically significant difference was found between days 1 and 3, and between days 5 and 30, as well as between days 7 and 30 (Wilcoxon Signed Ranks Test, P < 0.05). Rapidly disappearing POS (within 1 week) had the highest percentage: 75% +/- 9.934. CONCLUSIONS: Following restoration of class I and II cavities with self-etching adhesive and nanofilled composite POS was established in 26.3% of the cases.

The smear layer in the root canal and its removal.

Instrumentation of the root canal during endodontic treatment produces a smear layer which is not uniformly attached to the canal wall. Its morphological structure comprises dentin particles, organic debris, odontoblast processes, microorganisms and their metabolic products. The view that has currently gained wide popularity holds that leaving the smear layer in the root canal contradicts the principles of efficient treatment as this might compromise the optimal progression of the healing process. The proven unfavorable effects of the smear layer on treatment outcome bring forward the necessity for additional application of agents aimed at its complete removal. As the smear layer has a complex structure, these agents should possess a potential for dealing with both its organic and inorganic components. The wide range of used medications includes different concentrations of sodium hypochlorite as a major irrigant of the root canal, chlorhexidine gluconate, chelating agents (EDTA), organic acids, combined preparations (MTAD), combined use of agents that can tackle both the organic and inorganic components. Lasers find manifold applications in various medical fields and can be regarded as a future solution to the problem of total smear layer removal. In the present review we have made a critical analysis of currently used agents placing the emphasis on the potential use of new medications, capable of attacking the smear layer.

Effectiveness and ergonomic features of different light sources for polymerization of composite resin materials.

INTRODUCTION: Besides the halogen curing lights, already accepted as standard equipment, diode and plasma-arc units for polymerization of filling materials have also been commercially available in Bulgaria in recent years. The present study was prompted by the lack of detailed scientific information about these novel light curing devices. AIM: 1. To evaluate the quality of polymerization achieved by different light curing units by measuring the quantity of residual monomer in the test specimens. 2. To classify the units according to their convenience features and polymerization abilities. MATERIALS AND METHODS: Five diode units from three different manufacturers, one plasma-arc unit and one halogen unit were used. The test specimens, made from the hybrid photopolymerizing material Illumine (Ortho Plus, France), Type II, radiopaque, color C1, were 2 mm high and 4 mm in diameter. They were cured for 40 seconds with the respective unit after which they were ground and 25 mg from each sample were immersed in 8 ml of 95% ethanol for extraction of the residual monomer. The quantity of the residual monomer was determined by the method of the standard straight line. Statistical analysis was performed with the analysis of variance and F-test. The comparisons in each group were made by the Tukey-Kramer test, the level of significance for the null hypothesis being P = 0.05. The complex evaluation of the units was made with the help of a scale, developed by us. RESULTS: The material polymerized by the halogen light demonstrated the smallest quantities of residual monomer of all the specimens. There was no statistically significant difference between the quantities of the residual monomer in the specimens polymerized by the plasma arc unit (PAC), OL2 and Elipar Free Light exp. Such a difference, however, existed when comparing the PAC unit and the 3M ESPE unit, working in a continuous irradiation mode, the former having more residual monomer. Polymerization by Elipar Free Light produced the smallest quantities of residual monomer of all other diode lights. The only exception was the comparison between OL2 and Elipar Free Light exp., where there was no difference. The diode light of 3M ESPE performed best of all units according to the criteria we used for evaluation of the light curing devices. CONCLUSIONS: 1. The intensity of radiation of the light source and the duration of polymerization are of crucial importance for the complete conversion of the monomer into polymer. 2. Diode technology has not yet been able to reach any halogen equipment with respect to quality of polymerization, despite some of its unquestionable advantages. 3. When choosing a light curing unit, the quality of polymerization is more important than the price and the offered additional features.

Residual monomer in a composite resin after light-curing with different sources, light intensities and spectra of radiation

O objetivo deste trabalho foi investigar a quantidade de monômero residual em resinas compostas fotopolimerizadas, empregando diferentes fontes de energia, variadas intensidades e espectros de radiação. As amostras de resina (4 mm de diâmetro e 2 mm de espessura) foram fabricadas em matrizes de Plexglass e polimerizadas com lâmpada halógena, LED e PAC por 40, 40 e 5 s, respectivamente. As amostras foram pulverizadas e 25 mg de cada uma foi imersa em 8 mL de etanol a 96% por 24 h para extração do monômero residual. A quantidade de monômero residual foi determinada pelo método padrão de linha reta. O espectro luminoso das diferentes fontes de energia foi projetado e analisado pelo espectro de absorção de soluções-padrão no comprimento de onda l= 275 nm. Os dados foram analisados estatisticamente pela dispersão de variância e pelo teste de Tukey-Kramer com nível de significância de 5%. Constatou-se que a lâmpada halógena resultou na menor quantidade de monômero residual com luz de intensidade suficiente. O espectro de radiação do PAC esteve entre 450 e 490 nm e foi de intensidade extremamente alta. Este fato impõe que sejam utilizados pulsos de curta duração, mas também pode levar à deterioração da polimerização. O LED apresentou o melhor espectro de radiação. Constatou-se a necessidade de aumentar a intensidade da luz.