Long-term clinical evaluation of direct resin composite restorations in vital vs. endodontically treated posterior teeth - Retrospective study up to 13 years.

OBJECTIVES: This retrospective study evaluated and compared the survival rate of Class II posterior direct resin based composite (RBC) restorations made in vital teeth (VT) and endodontically treated teeth (ETT). The influence of risk factors on the long-term performance of restorations was also investigated. METHODS: Patients (n=245) receiving RBC posterior restorations between 2004 and 2012 were selected. A total of 597 restorations (485 in VT, 112 in ETT) with minimum 2.5-3mm remaining cusp thickness, made with the same brand of RBC and adhesive, were evaluated using the USPHS criteria. Data were analyzed with Mann-Whitney, Chi-square and Fisher's Exact Test, Extended Cox-regression and Kaplan-Meier analysis (p<0.05). Relative risk ratio was estimated for each evaluated parameter. RESULTS: The mean observation period was 8.6±2.3 years. An annual failure rate in VT and ETT of 0.08% and 1.78%, respectively, was detected. The reasons of failures included restoration fracture, secondary caries in VT; vertical root fracture, cusp fracture, restoration fracture, secondary caries and loss of adhesion in ETT. Significantly better performance was observed in RBCs of VT for each evaluated parameter. Among the evaluated risk factors only occlusal stress affected negatively the survival of RBC in ETT (Hazard Ratio 37.1; CI95% 8.4-163.7). SIGNIFICANCE: Although, there is significant difference in the success rate of RBCs in VT (98.97%) and ETT (76.8%), the long-term (6-13 years) durability of Class II RBCs with 2.5-3mm cusp thickness in ETT is also clinically acceptable. The presence of occlusal stress decreases the survival of RBCs in ETT.

Piezosurgical management of sealer extrusion-associated mental nerve anaesthesia: A case report.

The present report describes a case where sealer extrusion (Sealapex) occurred during root canal obturation of a left lower second premolar tooth, and the patient experienced sudden pain and followed by complete anaesthesia of the lower lip. After 3 weeks of conservative therapy and an unaltered anaesthesia period, piezosurgical removal of the extruded sealer and root-end resection was performed despite the direct contact with the mental neurovascular bundle. At suture removal, 1 week after surgery, there was no improvement in sensation. Two weeks after the operation, the patient reported some changes, including a short paraesthesia period alternating with anaesthesia. At the fourth post-operative week, neurosensory function recovered completely. This case represents successful use of the piezoelectric technique for mental nerve decompression and periapical surgery of a lower second premolar with close contact of the mental nerve.

Factors affecting ultrasonic removal of separated endodontic instruments: A retrospective clinical study.

OBJECTIVE: The goal was to investigate the clinical value of two-dimensional radiographs and different radiographic measurement techniques before instrument removal with a microsonic technique. The aim was to find an easy-to-use technique for predicting the success of removal and case evaluation. Additionally the quality of root canal filling after instrument removal was assessed. METHOD AND MATERIALS: This retrospective study analyzed patients' records and preoperative and postoperative periapical radiographs made using the paralleling technique. On preoperative radiographs, canal access angle and Schneider and Weine angle of root canal curvature were measured and compared. The Schäfer method was used for measuring the radius of curvature. In cases of successful removal taper, homogeneity and length of obturation were evaluated on postoperative radiographs. RESULTS: A total of 123 cases of instrument removal were investigated. In total, 97 fragments (78.9%) were removed successfully. Statistical analysis was performed with Pearson's chi-square and Fisher's exact test (α < .05). The site of fragment relative to canal curvature, canal access angle, and Schneider angle significantly influenced the success of removal. The highest chance of removal failure was associated with > 20 degrees of canal access angle and > 40 degrees of Schneider angle. Only 26.3% of obturations met all technical standards. Altered taper could be identified in 64.2% and was always associated with ledge formation. CONCLUSION: Microsonic removal is a successful method to retrieve separated instruments. The use of only one radiographic measurement technique is not sufficient to precisely evaluate root canal anatomy, case difficulty, and chance of successful removal before instrument removal on a periapical radiograph. Postoperative root canal fillings are mainly substandard.

Comparison of working length control consistency between hand K-files and Mtwo NiTi rotary system.

BACKGROUND: The purpose of this study was to investigate the consistency of working length control between hand instrumentation in comparison to engine driven Mtwo nickel-titanium rotary files. MATERIAL AND METHODS: Forty extracted maxillary molars were selected and divided onto two parallel groups. The working lengths of the mesiobuccal root canals were estimated. The teeth were fixed in a phantom head. The root canal preparation was carried out group 1 (n=20) with hand K-files, (VDW, Munich, Germany) and group 2 (n=20) with Mtwo instruments (VDW, Munich, Germany). Vestibulo-oral and mesio-distal directional x-ray images were taken before the preparation with #10 K-file, inserted into the mesiobuccal root canal to the working length, and after preparation with #25, #30 and #40 files. Working lenght changes were detected with measurements between the radiological apex and the instrument tips. RESULTS: In the Mtwo group a difference in the working competency (p<0.05) could be noticed only in the vestibulo-oral direction from #10 to #40 file. The hand instrument group showed a significant difference in working length competency for each larger file size (p<0.05) (ANOVA). Regression analysis in the hand instrumentation group indicated a working length decrease with a mean of 0,2 mm after each consecutive file size (p<0.01). CONCLUSIONS: The outcome of our trial indicated a high consistency in working length control for root canal preparation under simulated clinical condition using Mtwo rotary files. Mtwo NiTi rotary file did therefore proved to be more accurate in comparison to the conventional hand instrumentation. KEY WORDS: Working length, Mtwo, nickel-titanium, hand preparation, engine driven preparation.

Retrospective evaluation of posterior direct composite restorations: 10-year findings.

OBJECTIVES: This 10-year retrospective study investigated the differences in the changes and the longevity of Class II restorations using 4 similar microhybrid resin composites (Filtek Z250, Herculite XR, Gradia Direct Posterior, Renew). METHODS: Data were collected from patient records. Those patients who received posterior restoration between 2001 and 2003, and who still visited the clinical practice for regular check-up visits were selected. A total of 225 adult patients (86 males, 139 females) with 701 restorations were evaluated by 2 operators using the USPHS criteria. Data were analyzed with Fisher's Exact Test, Pearson's Chi-Square Test and Kaplan-Meier analysis (p<0.05). RESULTS: A failure rate of 2.1% was detected. The reasons of failures included restoration fracture, secondary caries and endodontic treatment. Similar survival rates for Gradia Direct Posterior (91.25%) and Renew (92.19%) were observed; better performance was observed with the Filtek Z250 (99.1%) and Herculite XR (98.64%). There was a higher probability of failure in 3 surface (n=10) than in 2 surface (n=5) restorations (p<0.001), and this rate was similar when molars (n=8) and premolars (n=7) were compared. The most frequent but clinically acceptable deficiency was the marginal discoloration. SIGNIFICANCE: All four microhybrid resin composites showed acceptable clinical durability in Class II restorations during the 10-year follow-up period, with an overall survival rate of >97.8%. Higher rates of failures and deficiencies were observed with the Renew (fracture) and Gradia Direct Posterior (color match), respectively.

[Retrospective study of direct composite restorations according to the USPHS criteria]. / Direkt kompozit restaurációk retrospektív vizsgálata USPHS kritériumrendszer alapján.

The purpose of this retrospective study was to evaluate and describe the occurrence of different deficiencies of composite restorations in molar and premolar teeth. Further aim was to investigate possible correlations between occurring malformations and the localization or size of the restorations. 240 class II composite restorations (in 85 patients) were involved in the study. Control examinations were carried out five years after restorations, according to the United States Public Health Services' criteria. Namely, anatomic form, marginal integrity, marginal stain, color stability, surface smoothness, and the presence of secondary caries or fractures of the restorations. The associations between variables were calculated by bivariate analyses using either Pearson chi-square or Fisher tests. P < 0.05 was considered significant. In 0.8% of the fillings, secondary caries and in 0.4% of the cases, fracture was found as a failure. The frequency of adjacent deficiencies were found as follows: color instability, 12.5%; marginal stain, 20.8%; anatomic deformity, 15.0%; failure of marginal integrity, 8.8%; and surface roughness, 2.5%. Color instability was significantly more frequent in premolar teeth, than in molars (P = 0.031). Color instability (P = 0.015), marginal stain (P < 0.001) and anatomic form malformation (P = 0.002) occurred more frequently in MOD restorations than in MO/OD fillings. Our results suggest that class II restorations are correct both functionally and esthetically in 98.8% of the cases, even after a 5-year-period.

Chemomechanical preparation by hand instrumentation and by Mtwo engine-driven rotary files, an ex vivo study.

OBJECTIVE: To compare the disinfecting efficacy of the sodium hypochlorite irrigation by root canal preparation with stainless steel hand files, taper 0.02 and nickel-titanium Mtwo files with taper 0.04-0.06. STUDY DESIGN: 40 extracted human teeth were sterilized, and then inoculated with Enterococcus faecalis (ATCC 29212). After 6 day incubation time the root canals were prepared by hand with K-files (n=20) and by engine-driven Mtwo files (VDW, Munich, Germany) (n=20). Irrigation was carried out with 2.5% NaOCl in both cases. Samples were taken and determined in colony forming units (CFU) from the root canals before and after the preparation with instruments #25 and #35. RESULTS: Significant reduction in bacterial count was determined after filing at both groups. The number of bacteria kept on decreasing with the extension of apical preparation diameter. There was no significant difference between the preparation sizes in the bacterial counts after hand or engine-driven instrumentation at the same apical size. Statistical analysis was carried out with Mann-Whitney test, paired t-test and independent sample t-test. CONCLUSIONS: Significant reduction in CFU was achieved after the root canal preparation completed with 2.5% NaOCl irrigation, both with stainless steel hand or nickel-titanium rotary files. The root canal remained slightly infected after chemo mechanical preparation in both groups. Key words:Chemomechanical preparation, root canal disinfection, nickel-titanium, conicity, greater taper, apical size.

[Direct comparison of working length determination by ProPex electronic apex locator and radiographic method--an in vitro study]. / ProPex apexlokátorral és radiológiai módszerrel végzett munkahossz-meghatározás összehasonlítása in vitro direkt eljárással.

The purpose of this study was to compare the accuracy of electronic and radiographical working length determination in extracted molars. Palatal root canals of twenty maxillary molars were used. Teeth were randomly divided into two groups. In case of the first group the working length was measured by apex locator (Propex, Dentsply-Maillefer), and in the second group it was measured with radiographic method (RVG, Trophy). The files, used for measuring the working length, were cemented into the teeth. The apical half of the root was ground, and the tips of the files visualised as well as the apical region of the root canal with the apical constriction. Standard digital photographs were taken from the prepared samples, and the distance between the tip of the file and the physiological foramen was measured. Two sample t test was used for statistical analysis. The physiological foramen was approached on average to 0.11 mm by the electronic method and to 0.58 mm by the radiological method. There was no significant difference in the measuring accuracy between the two methods (p=0.10). The electronic and radiological working length determination may prove to show an equivalent consistency.

Comparison of radiographic and electronical working length determination on palatal and mesio-buccal root canals of extracted upper molars.

OBJECTIVE: The objective of this work was to compare the accuracy of working length determination of ProPex (Dentsply-Maillefer) electronic apex locator (EAL) to the radiographic method on extracted molars. STUDY DESIGN: Root canal length was determined using the electronic apex locator and conventional radiographic method. Digital radiographs were taken and the distance between the tip of the file and the radiographic apex was measured. Mann-Whitney and chi(2) tests were used for the statistical analysis. RESULTS: The average distance between the tip of the file and the radiographic apex in the mesio-buccal canals was 0.46 mm with the radiologic method, and 0.23 mm with EAL, and 0.43 mm and 0.31 mm in the palatal canals, respectively. The difference at the mesio-buccal canals was significant (Mann-Whitney test P = .048). The number of overextensions was higher in the EAL group. CONCLUSION: The desired position of the file achieved by the EAL proved to be more accurate in the mesio-buccal canals than with the radiologic method alone.

[In vitro comparison of root canal preparation with step-back technique and GT rotary file--a nickel-titanium engine driven rotary instrument system]. / Step-back technikával és GT rotary file nikkel-titanium gépi forgómuszerrel végzett gyökércsatorna-elokészítés in vitro vizsgálata.

The aim of the authors' study was to compare the remaining root canal wall thickness and the preparation time of root canals, prepared either with step-back technique, or with GT Rotary File, an engine driven nickel-titanium rotary instrument system. Twenty extracted molars were decoronated. Teeth were divided in two groups. In Group 1 root canals were prepared with step-back technique. In Group 2 GT Rotary File System was utilized. Preoperative vestibulo-oral X-ray pictures were taken from all teeth with radiovisiograph (RVG). The final preparations at the mesiobuccal canals (MB) were performed with size #30 and palatinal/distal canals with size #40 instruments. Postoperative RVG pictures were taken ensuring the preoperative positioning. The working time was measured in seconds during each preparation. The authors also assessed the remaining root canal wall thickness at 3, 6 and 9 mm from the radiological apex, comparing the width of the canal walls of the vestibulo-oral projections on pre- and postoperative RVG pictures both mesially and buccally. The ratios of the residual and preoperative root canal wall thickness were calculated and compared. The largest difference was found at the MB canals of the coronal and middle third level of the root, measured on the distal canal wall. The ratio of the remaining dentin wall thickness at the coronal and the middle level in the case of step-back preparation was 0.605 and 0.754, and 0.824 and 0.895 in the cases of GT files respectively. The preparation time needed for GT Rotary File System was altogether 68.7% (MB) and 52.5% (D/P canals) of corresponding step-back preparation times. The use of GT Rotary File with comparison of standard step-back method resulted in a shortened preparation time and excessive damage of the coronal part of the root canal could be avoided.