ENDO, 03/2018

In the present study root canal preparation in curved root canals in extracted teeth was compared using either the vibratory Self-Adjusting File (SAF) or the rotary BioRace NiTi system. The issues investigated were longitudinal and cross-sectional preparation shape, root canal cleanliness and the incidence of procedural mistakes. No significant differences were found with respect to the above-listed topics investigated in this study. Both NiTi systems can be recommended for clinical use. Keywords: BioRace, canal cleanliness, root canal preparation, Self-Adjusting File, shaping ability, working safety

The C-shaped configuration of the root and root canal system is an unusual anatomical variation in mandibular first and second premolars. It is categorised as a 'C' due to the transverse morphology of the root and the root canal. The main anatomical characteristic is the presence of an invagination groove caused by Hertwig epithelial sheath faults during root development. This case report describes the root canal treatment of a C-shaped configuration of a mandibular first premolar, identified by means of cone beam computed tomography. Keywords: anatomical variation, C-shaped root, C-shaped root canal, cone beam computed tomography, dental anomalies, mandibular premolar, tomography, tooth morphology

Introduction: The aim of this study was to compare the tooth length measured on already existing cone beam computed tomography (CBCT) scans, the reading of electronic apex locater in vivo and the actual length of the same tooth after extraction. Methods: A total of 178 canals were measured three times in this study. The aim of this study was to compare the tooth length measured on already existing CBCT scans, then clinically with the aid of two different electronic apex locators. After that, teeth were extracted, and the actual length of the canals was measured and considered as the gold standard. The means and standard deviations of electronic apex locators' lengths, CBCT and actual lengths in the mesiobuccal, distobuccal and palatal roots were statistically analysed using the one-way ANOVA test (P ≤ 0.05). Results: No statistically significant difference was found between the CBCT measurements, the apex locator readings and the actual tooth length. Conclusion: A pre-existing CBCT scan can reliably be used for tooth length determination. Keywords: actual tooth length, CBCT, electronic apex locator, Rootor, Root ZX mini

Objective: The purpose of this study was to compare a manually operated preparation system such as ProTaper manual file and its counterpart engine-driven rotary instrument regarding the transportation of standardized simulated root canals. Materials and methods: Forty resin-simulated root canals were filled with ink, and pre-instrumentation images were acquired using a stereomicroscope. Samples were divided into two groups according to the instrument's operation mode. Preparation was performed using ProTaper manual or rotary up to size F2. Pre- and post-instrumentation images were obtained and superimposed for measurement at eight different measuring points (0 to 7 mm from apex). Results: There were no significant differences between the groups at levels 0, 2, 3 or 7 mm. At levels 1, 4, 5 and 6 mm, engine-driven mode with rotary ProTaper instrumentation promoted higher canal transportation than manually operated mode using ProTaper manual (P 0.05). In both groups, the pronounced canal transportation occurred at level 5 mm. Conclusions: Both operation modes caused deviation in simulated standardized root canals; however, the manually operated system with ProTaper manual files generated significantly less deviation than the motor-driven mode using rotary ProTaper instruments. Keywords: canal transportation, centring ability, curved canal, ProTaper

Objective: It was the aim of this case series to evaluate the success rate of non-surgical retreatment of teeth with persisting apical periodontitis after apicectomy. Materials and methods: Apical healing was evaluated radiographically in eighty-six consecutive cases of non-surgical retreatment of apicectomies with persisting apical periodontitis performed in a private dental practice from 2003 to 2011. Observation time was at least 12 months. Evaluation of pretreatment and recall radiographs was independently performed by two external dentists not involved in the treatment of the teeth using two-fold magnification. In cases of disagreement a consensus was reached by joint discussion. Success was defined as complete radiographical resolution of periapical lesions and absence of clinical symptoms at the time of the recall visit. Incomplete healing was not rated as success. Results: The success rate was 69.5%, with an additional 10.2% classified as healing, and 20.3% as failures. Conclusions: Non-surgical retreatment of teeth presenting with a persisting apical lesion after apicectomy can be regarded a reasonable treatment option with a limited prognosis in terms of apical healing. Keywords: apicectomy, MTA, non-surgical retreatment, success rate

This case report aimed to demonstrate the importance of cone beam computed tomography (CBCT) for the diagnosis, follow-up and treatment planning of internal root resorption (IRR). A 10-year-old male patient was referred for clinical examination, which revealed a dental fusion in the mandibular right lateral incisor (tooth 42). One year after the sectioning of the fused teeth, a well demarcated radiolucency in tooth 42 was observed by radiography, similar to IRR. CBCT scanning was performed in order to distinguish between external and internal root resorption. After the IRR diagnosis, root canal treatment was performed and no progression of the lesion was observed after 2 years. Thus, CBCT images were useful to delimit the extent of the IRR lesion, being able to identify possible communication sites with the periodontal space, and should be applied in IRR cases. Keywords: cone beam computed tomography, diagnostic radiograph, resorption

Contemporarily, most clinicians use the cold test on teeth suspected to have pulpitis. The origins of this diagnostic technique are vague, as is the pathophysiological interpretation of the patient's responses. Correlations are varied relative to the status of the pulp tissue. There are numerous questions regarding this diagnostic approach, many of which remain unanswered. Was this diagnostic test chosen based on the patient's signs and symptoms? Did it offer a direct and accurate picture of the status of the dental pulp? Could it take into account the presence of large amounts of reparative dentine that may have formed in the tooth in question? Was it accurate in the presence of the tooth that displayed a periapical lesion ... or was it even necessary in these cases? This paper addresses both the history of the use of cold in dentistry and some of the proposed origins and constraints of this technique for pulpal diagnosis, along with clinical and scientific perspectives. Keywords: cold test, dental pulp, diagnostic testing, pulpitis, vitality

Objective: The aim of this research was to study in primary teeth the relationship between the accuracy of the electronic apex locator Root ZX and each of the following factors: root canal curvature, canal size, the position of the apical foramen and the degree of resorption. Materials and methods: The pulp tissue was removed from 71 root canals of 21 primary molars. After irrigation with NaOCl (1%), the working length of 71 root canals was measured by Root ZX (Morita, Tokyo, Japan) clinically prior to extraction. The actual length of each canal was recorded after extraction, and compared with the electronically measured length. Results: Paired samples t test was performed at a significance level of 95% (P ≤ 0.05); electronically measured values were lower than those of the actual length, with a tendency to estimate the root canal length just short of the apex. Both Cronbach's alpha and intraclass correlation coefficient values were near to 1. Chi-square analysis showed that P > 0.05 for canal curvature, file size and resorption degree, but P 0.05 for the position of the apical foramen. Mann-Whitney U test P values were 0.05 when comparing between the "≥ 2.0 mm before the apex" subgroup and other subgroups. Conclusions: The accuracy of Root ZX is acceptable in primary teeth, and is not affected by root canal curvature, canal size or the degree of resorption. However, when the apical foramen is ≥ 2.0 mm short of the anatomical apex, the possibility of incorrect measurement increases. Keywords: apex locator, canal curvature, primary teeth, resorption, root canal instruments, Root ZX, working length