Sebastian Bürklein

Incidence of Dentinal Defects after Root Canal Preparation: Reciprocating versus Rotary Instrumentation

INTRODUCTION The purpose of this study was to evaluate the incidence of dentinal defects after root canal preparation with reciprocating instruments (Reciproc and WaveOne) and rotary instruments. METHODS One hundred human central mandibular incisors were randomly assigned to 5 groups (n = 20 teeth per group). The root canals were instrumented by using the reciprocating single-file systems Reciproc and WaveOne and the full-sequence rotary Mtwo and ProTaper instruments. One group was left unprepared as control. Roots were sectioned horizontally at 3, 6, and 9 mm from the apex and evaluated under a microscope by using 25-fold magnification. The presence of dentinal defects (complete/incomplete cracks and craze lines) was noted and analyzed by using the chi-square test. RESULTS No defects were observed in the controls. All canal preparation created dentinal defects. Overall, instrumentation with Reciproc was associated with more complete cracks than the full-sequence files (P = .021). Although both reciprocating files produced more incomplete cracks apically (3 mm) compared with the rotary files (P = .001), no statistically significant differences were obtained concerning the summarized values of all cross sections (P > .05). CONCLUSIONS Under the conditions of this study, root canal preparation with both rotary and reciprocating instruments resulted in dentinal defects. At the apical level of the canals, reciprocating files produced significantly more incomplete dentinal cracks than full-sequence rotary systems (P < .05).

Impact of nickel–titanium instrumentation of the root canal on clinical outcomes: a focused review

Nickel–titanium (NiTi) root canal instruments have improved the technical quality of enlarging and shaping. These instruments have been shown to prepare even severely curved root canal with fewer procedural errors than traditional stainless steel hand instruments. While it would appear that these instruments might enhance clinical outcomes, very few studies have assessed their impact when used in primary root canal treatment. Clinical studies investigating the outcome of primary root canal treatment using nickel–titanium hand or rotary instruments were identified (MEDLINE database) using appropriate key words in an attempt to determine if there have been enhanced outcomes with these instruments. Evidence from one clinical trial suggests that (i) better maintenance of the original canal curvature and shape results in increased success rates and (ii) that ledging of root canals results in reduced success rates. Evidence from two studies indicates that the use of NiTi—either hand or rotary—instruments significantly increases success rates of primary nonsurgical root canal treatment compared with the use of stainless steel hand instruments, while three investigations failed to show any significant differences.

Shaping ability of different nickel-titanium systems in simulated S-shaped canals with and without glide path.

INTRODUCTION The objective of this study was to compare the shaping ability of different rotary and reciprocating nickel-titanium file systems with and without previous glide path preparation in simulated S-shaped canals. METHODS One hundred twenty S-shaped canals in resin blocks were prepared to an apical size 25 by using Reciproc, WaveOne, HyflexCM, F360, and OneShape systems either with or without previous glide path preparation (Pathfile) (12 canals/group). Material removal was measured at 20 measuring points, beginning 1 mm from the end point of preparation. Incidence of canal aberrations (zip/elbow, ledge formation), preparation time, and instrument failures were also recorded. Statistical analyses were performed by using analysis of variance and Tukey and χ(2) tests. RESULTS For all systems, glide path preparation exerted no significant effect on preparation times (P > .05). Glide path preparation had no influence on the incidence of canal aberrations and instrument fractures (P > .05), with no significant differences between the 5 systems (P > .05). Glide path preparation had no influence on the centering ability of all systems (P > .05). On average, canals prepared with F360, OneShape, and HyflexCM remained better centered compared with those enlarged with WaveOne and Reciproc. CONCLUSIONS Under the conditions of this study, glide path preparation had no significant impact on canal straightening. Less tapered instruments maintained the original canal curvature better than instruments having greater tapers.

Occurrence of Hypercementosis in a German Population

INTRODUCTION The purpose of this study was to assess the occurrence of hypercementosis in a selected German dental school patient population. METHODS A total of 800 full-mouth periapical radiographic series were screened. The radiographs were evaluated under optimal conditions by using double magnifying glasses. A total of 18,589 teeth including third molars were evaluated. The relative incidence of hypercementosis and the correlation regarding the location (left-side versus right-side occurrence, maxillary versus mandibular, and anterior versus posterior teeth) and between men and women were recorded and analyzed by using the χ(2) test. RESULTS Eleven patients were found to have hypercementosis, 10 women and 1 man (P < .05). Of these, 5 of 11 (45.46%) had only 1 tooth with hypercementosis, and 6 had more than 1 (54.54%). In total, 22 teeth associated with hypercementosis were found. Seven maxillary teeth were associated with hypercementosis (31.82%) and 15 mandibular teeth (68.18%) (P = .198). No significant differences were found regarding left-side and right-side occurrence of the affected teeth (P > .05). Hypercementosis was significantly more often associated with premolars and molars than with incisors (P < .01). Hypercementosis was found in 11 of 800 patients (1.33%). It was identified in 22 of the 18,589 teeth examined (0.12%). CONCLUSIONS The occurrence of hypercementosis among this selected German population was rare. Female patients were approximately 10 times more often affected than male patients. Mandibular teeth were approximately twice as often associated with hypercementosis as maxillary teeth.

Evaluation of the Root Canal Anatomy of Maxillary and Mandibular Premolars in a Selected German Population Using Cone-beam Computed Tomographic Data

Introduction The aim of this study was to investigate the number of roots and the morphology of the root canals of maxillary and mandibular premolars in a selected German population. Methods Randomly selected full‐size cone‐beam computed tomographic images were collected from 700 patients (45% men and 55% women, average age = 50.21 years). This resulted in a total of 644 first and 512 second maxillary premolars as well as 1044 first and 871 second mandibular premolars. The total number of roots and root canals, the frequency and correlations between the left and right sides, and the incidence in men and women were recorded and statistically analyzed using the Fisher exact and chi‐square tests. Canal configurations were classified according to the Vertucci classification. Results First maxillary premolars mainly had 2 roots (1 root: 36.4%, 2 roots: 62.4%, and 3 roots: 1.2%) with predominantly 2 canals (88.4%). The majority of second maxillary premolars had 1 root (82.6%), but 2 root canals (56.3%) occurred more frequently than 1 canal (43.1%). In the first and second mandibular premolars, 1 root was found predominantly (90.76% and 98.16%, respectively) with 1 canal (77.9% and 96.0%), whereas 2 canals were less common (21.9% and 3.6%). Three roots (0%, <0.11%) and 3 canals (0.2%; 0.4%) were rarely found. Vertucci classifications were heterogeneously distributed. Men showed significantly more roots and root canals compared with women (P < .05), with the exception of the second mandibular premolars. Conclusions This cone‐beam computed tomographic study confirmed previous anatomic and morphologic investigations. When treating premolars, the likelihood of additional root canals should be considered. HighlightsOut of more than 1000 cone‐beam computed tomographic (CBCT) scans, a total of 700 full‐size CBCT scans showing both the mandible and the maxilla including the root apices of all teeth were retrospectively selected and randomly analyzed concerning the number of roots and the root canal anatomy of the mandibular and maxillary premolars.CBCT data were sufficiently accurate in performing anatomic studies.In total, men present significantly more roots and root canals compared with women in maxillary and mandibular premolars, with the exception of the second mandibular premolar.

Percentage of Gutta-percha Filled Areas in Canals Obturated with Cross-linked Gutta-percha Core-carrier Systems, Single-Cone and Lateral Compaction Technique

INTRODUCTION The aim of this study was to compare different obturation techniques in terms of the percentage of gutta-percha filled areas (PGFA), sealer filled areas (PSFA), and voids in straight root canals prepared with different instruments. METHODS One hundred sixty extracted single-rooted mandibular premolars with straight canals were allocated into 10 groups (n = 16 teeth per group): A, manual instrumentation + lateral compaction (LC); B, Mtwo + GuttaFusion (GF); C, Mtwo + LC; D, Mtwo + single-cone (SC); E, Reciproc + GF; F, Reciproc + LC; G, Reciproc + SC; H, WaveOne + GuttaCore (GC); I, WaveOne + LC; and J, WaveOne + SC. Apical preparation was size 40 in all groups, and AH Plus was used as a sealer. The teeth were sectioned at 2, 4, 6, and 8 mm from the apex. The total area of each canal segment was measured, and the areas were converted to PGFA, PSFA, and voids. Data were subjected to the Kruskal-Wallis and post hoc Dunn tests. RESULTS At the 2-mm level, no significant differences in terms of PGFA and PSFA were obtained (P > .05). At all other levels, canals filled with GC and GF produced significantly higher PGFA and significantly lower PSFA than all other groups (P < .05). At the 2-mm, 4-mm, and 6-mm levels, canals filled with GC and GF showed less voids than group A (P < .05). CONCLUSIONS Under the conditions of this study, independent of the instrument used for canal preparation, GuttaCore and GuttaFusion produced very homogenous root canal fillings with high PGFA and a low incidence of voids.

Minimally invasive endodontics.

Minimally invasive endodontics (MIE) aims to preserve the maximum of tooth structure during root canal therapy. In the last 15 years there has been rapid progress and development in endodontics, making treatment procedures safer, more accurate, and more efficient. Meanwhile, reproducible results can be achieved even in difficult root canal morphologies with severe or double curvatures. In addition to various material improvements, the implementation of the surgical microscope (SM) in endodontics is an important innovation, making it possible to optimize each step in the treatment protocol in terms of substance preservation.

Review of the dental implications of X-linked hypophosphataemic rickets (XLHR)

ObjectivesThe aim of this article was to review the dental implications of X-linked hypophosphataemic rickets (XLHR) and to provide suggestions regarding the dental treatment of these patients.Materials and methodsThe following search items “x-linked hypophosphataemia, hypophosphataemic rickets, vitamin D-resistant rickets” were used for literature search. Only full-text articles were analysed and summarized to get an overview of the different treatments and outcomes of hypophosphataemic patients.ResultsRadiographically, very large pulp chambers with an abnormally high pulp volume/tooth volume ratio, suggesting taurodontism, are often evident. The affected teeth are characterised by a thin enamel layer and dentinal defects. The gender distribution of hypophosphataemic patients is almost equal, but postpubertary males seem to show a trend to develop more severe dental symptoms of the disease. Abscesses without any signs of dental caries or trauma are frequent findings. The most often affected teeth are incisors followed by molars and premolars.ConclusionsTreatment options include frequent dental examination, application of topical fluoride varnish and sealing of pits and fissures to prevent microbial invasion that may result in pulpitis and further endodontic complications.Clinical relevanceX-linked hypophosphataemic rickets is associated with marked structural alterations of dental hard tissues and the development of multiple abscesses and sinus tracts of dental origin. Therefore, profound knowledge of the various dental implications of XLHR is required to provide these patients with the best possible treatment options.