The extrusion of root canal cement containing paraformaldehyde into the inferior alveolar nerve canal resulting in infection and numbness.

AIM: To describe the impact of extruded paraformaldehyde-containing root canal cement into the inferior alveolar nerve canal following a delay in removal and the subsequent management of the case. SUMMARY: A 30-year-old man was referred for management of prolonged anaesthesia in the right mandibular region following root canal treatment. Panoramic and cone beam computed tomography findings revealed that overextruded root canal cement had penetrated into the inferior alveolar nerve canal beyond the distal root of the mandibular right second molar (tooth 47). The root canal cement contained paraformaldehyde. Initially, the patient refused surgical removal of the cement. However, after 3.5 months, the patient returned with an acute infection in the same region. After resolution of the acute abscess and root canal retreatment, surgical treatment was performed under general anaesthesia. Granulation tissue and necrotic bone were found associated with the cement.

Use of cone-beam computed tomography to evaluate C-shaped root canal systems in mandibular second molars in a Turkish subpopulation: a retrospective study.

AIM: To use cone-beam computed tomography (CBCT) to evaluate the prevalence and anatomical features of C-shaped canals in permanent mandibular second molars amongst members of a Turkish population. METHODOLOGY: An endodontist and oral radiologist examined CBCT images of 271 Turkish mandibular second molars to determine the presence of C-shaped canals and their anatomical features. Root canal configurations at five different levels were categorized using the classification of Fan et al. (Journal of Endodontics, 30, 2004a,b, 899-903; 904-8). Bilateral or unilateral occurrence of C-shaped canals and their relationships with gender, age and tooth position were examined and statistically analysed using the chi-squared test. RESULTS: Of the 271 mandibular second molars examined, 24 (8.9%) molars from 17 patients had a C-shaped root canal system. The prevalence of bilateral C-shaped canals was 6.3% amongst 111 patients with bilateral mandibular second molars. There were no significant differences in the distribution of C-shaped canals with respect to gender or age. Only one tooth had the same canal configuration from the orifice to the apex. In the remainder of the teeth, the cross-sectional canal configuration changed at different levels of the root. CONCLUSIONS: The configuration of C-shaped canals varied along the length of the root. The prevalence of C-shaped canals in mandibular second molars in this Turkish population was lower than in other Asian populations.

Efficacy of reciprocating and rotary systems for removing root filling material: a micro-computed tomography study.

This study aimed to use micro-computed tomography (micro-CT) imaging to evaluate the efficacy of the reciprocating and rotary systems for the removal of root filling materials in comparison with hand files. Thirty maxillary incisor teeth were prepared with ProTaper Universal (PTU) system, filled using cold lateral condensation and randomly divided into three groups of ten teeth each. The root fillings were removed with WaveOne Reciprocating and ProTaper Universal Re-treatment (PTU-R) systems and hand files. Micro-CT was used to scan the specimens before and after each treatment step. Percentage of volume of residual root filling was measured. The operating time was recorded. PTU-R instruments yielded better results for removing filling material, even though there was no statistically significant difference between PTU-R and WaveOne groups. Reciprocating and rotary systems showed similar performances in terms of efficacy and operating time for root filling removal.