ABSTRACT
BACKGROUND: Intraradicular procedures remove radicular dentin and jeopardizing longevity of a tooth. Traditional in vitro methods used to determine the remaining dentin thickness (RDT) have limitations. AIM: The aim is to evaluate, using cone-beam computed tomography (CBCT), RDT following rotary instrumentation and post space preparation in buccal and palatal roots of maxillary first premolars. MATERIALS AND METHODS: Twenty-three maxillary first premolars with two roots were selected. CBCT images were taken preoperatively, after instrumentation and Parapost 3 and 4 preparation (CBCT 1, 2, 3, and 4). RDT was measured 5 mm above apex, 1 mm below furcation, and 1 mm above furcation (Levels 1, 2, and 3). Data were analyzed using ANOVA and post hoc Tukey's test (P = 0.05). RESULTS: Rotary instrumentation and post space preparation reduced RDT in all walls of buccal and palatal roots. Post space preparation with Parapost 3 and 4 reduced RDT in the palatal wall of buccal root to <1 mm and Parapost 4 reduced all walls to 1 mm of dentin. CONCLUSION: Post space preparation in maxillary first premolars should be performed cautiously. It is safer to place a post in the palatal root of this tooth and limit preparation to Parapost 3.
ABSTRACT
Aim. To compare the microleakage in class II composite restorations without a liner/with resin modified glass ionomer and flowable composite liner. Method. Forty standardized MO cavities were prepared on human permanent mandibular molars extracted for periodontal reasons and then divided into 4 groups of ten specimens. The cavity preparations were etched, rinsed, blot dried, and light cured and Adper Single Bond 2 is applied. Group 1 is restored with Filtek P60 packable composite in 2 mm oblique increments. Group 2 is precure group where 1 mm Filtek Z350 flowable liner is applied and light cured for 20 sec. Group 3 is the same as Group 2, but the liner was cocured with packable composite. In Group 4, 1 mm RMGIC, Fuji Lining LC is applied and cured for 20 sec. All the teeth were restored as in Group 1. The specimens were coated with nail varnish leaving 1 mm around the restoration, subjected to thermocycling, basic fuchsin dye penetration, sectioned mesiodistally, and observed under a stereomicroscope. Results. The mean leakage scores of the individual study groups were Group 1 (33.40), Group 2 (7.85), Group 3 (16.40), and Group 4 (24.35). Group 1 without a liner showed maximum leakage. Flowable composite liner precured was the best.
ABSTRACT
BACKGROUND: Controlled, uniformly tapered radicular preparation is a great challenge in endodontics. Improper preparation can lead to procedural errors like transportation of foramen, uneven dentine thickness, stripping of root canal, formation of ledge, zip, and elbow in curved canals. These procedural errors and their sequel can adversely affect the prognosis of treatment. AIM/OBJECTIVES: The present in vitro study aims to evaluate canal preparation based on the following factors: canal transportation, remaining dentine thickness and comparing centering ability between hand Ni-Ti K files and ProTaper rotary Ni-Ti instruments using computed tomography (CT). MATERIALS AND METHODS: For evaluation, 30 mesiobuccal roots of maxillary molars were selected. Of these, 15 roots were distributed into two groups where Group 1 included hand instrumentation with Ni-Ti K-files; and Group 2 comprised ProTaper NiTi rotary system. Pre instrumentation and post instrumentation three-dimensional CT images were obtained from root cross-sections that were 1 mm thick from apex to the canal orifice; scanned images were then superimposed and compared. RESULT: It was observed that the manual technique using hand Ni-Ti K-file produced lesser canal transportation and maintained greater dentine thickness than the rotary ProTaper technique at middle and coronal third and this difference was statistically significant. No significant difference was seen with regard to canal transportation and remaining root dentine at apical levels. With regard to centering ratio, no significant difference was seen between both the groups at all levels. CONCLUSION: ProTaper should be used judiciously, especially in curved canals, as it causes higher canal transportation and thinning of root dentine at middle and coronal levels. None of the groups showed optimal centering ability.
