Owing to its favorable impacts on the properties of materials, nanotechnology is rapidly growing. Adding nano particles to a material can significantly affect its mechanical and physical properties. In recent years, nanotechnology has been applied in the field of medical sciences in order to enhance the quality of treatment procedures. This technology can be used in various aspects of dentistry. In the present study, a comprehensive literature review is conducted on the applications of nanotechnology in endodontics. It was concluded that nanotechnology can be utilized in fillers, irrigants and photodynamic therapy to achieve more beneficial results. Based on the reviewed studies, it is well acknowledged that antibacterial nano particles can be used for disinfection and have shown acceptable efficacy in elimination of bacterial cells. Moreover, nanotechnology is applicable to sealers used in endodontics. By using nano-sized materials, anti-leakage property of the sealer can be enhanced. In addition, nanotechnology can be applied in photodynamic therapy in endodontics. By using nanotechnology, it is possible to enhance the efficacy of this method.

https://nmj.mums.ac.ir/article_11153_28c4b11bc8a40ffa50f108a8c87e8e36.pdf

Applications of nanotechnology in endodontic: A Review

This study aimed at identifying the course of the mandibular canal, the presence of anterior loop and accessory mental foramen, as well as verifying the association between these variables through the analysis of cone beam computed tomography (CBCT) exams. CBCT images were analyzed to identify the type of mandibular canal path, classified into three types: (I) catenary; (II) progressive descending; and (III) straight. In addition, the presence of anterior loop and accessory mental foramen was analyzed. The variables were summarized by measures of absolute frequency, relative, mean and standard deviation. The Chi square and Fisher’s exact tests were used in the comparative analysis of the frequency distribution. The level of significance was 5%. The most frequent mandibular canal course was straight type (74.4%), followed by catenary (19.4%) and finally the progressive descending (6.2%). It was observed a prevalence of 10.2% for anterior loop and 7.9% for accessory mental foramen. There was no association between the presence of anterior loop (P = 0.798) and accessory mental foramen (P 0.480) with the mandibular canal course pattern, as well as no association between the anterior loop and the presence of the accessory mental foramen (P = 0.407). The CBCT analysis is the best methodology for the investigation and localization of mandibular anatomical variations, which provides a good image quality of the bone tissue and details of the anatomical structures, reducing the risk of injury to the lower alveolar vascular-nervous bundle and, consequently, cause paralysis and hemorrhage in the anterior region of the mandible and adjacent structures.

Location of the course of the mandibular canal, anterior loop and accessory mental foramen through cone-beam computed tomography.

The aim of this study was to evaluate the frequency and location of accessory mental foramen (AMF) in a Turkish population using cone beam computerized tomography (CBCT). CBCT images of 1005 patients were retrospectively reviewed from the archive of the Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Izmir Katip Celebi University. The prevalence, size, and localization of AMFs were assessed according to gender and age. In addition, the vertical and horizontal dimension of the mental foramen (MF) with and without AMF was measured to investigate the relationship between MF dimensions and the presence and absence of AMF. The average distance between the MF and AMF was also calculated. All measurements were then analyzed statistically. A total of 149 AMFs in 123 (12.23%) patients were identified on the CBCT images of the 1005 patients reviewed. There was no significant correlation between presence of AMF and gender (p  = 0.152). The most common localization of an AMF with respect to the MF was posterio-inferior (n = 52; 34.89%). A statistically significant difference was also found between the vertical and horizontal dimensions of the MF with and without AMF (p  < 0.05). The results of this study demonstrate the high prevalence of AMF in the studied Turkish population. Considering the high prevalence and the structures passing through it, recognition of AMF and its detection using CBCT is important to prevent complications that may occur during and after surgical procedures.

Cone-beam computed tomographic evaluation of accessory mental foramen in a Turkish population

The mental foramen is an important anatomic landmark located on the buccal aspect of the mandible, typically near the apex of the second premolar. Mental foramina exhibit many anatomical variations, including differences in size, shape, position, and number. The most frequent type of variation in number is the presence of double mental foramen, which has a reported incidence ranging from 1.4 to 12.5%. The incidence of triple mental foramen ranges from 0.7 to 1.2%. The frequency of accessory mental foramina varies among ethnic groups, with a low incidence in white Caucasian populations. At present, cone beam computed tomography (CBCT) is the diagnostic tool of choice for examining the maxillofacial region, and the high spatial resolution of CBCT allows accurate three-dimensional analysis of mental foramen variations. The present report describes an unusual case of five mental foramina in a 24-year-old white European male diagnosed by CBCT.

Five mental foramina in the same mandible: CBCT findings of an unusual anatomical variant

Background: Mental foramen (MF) is an important landmark for administration of local anesthesia in surgical procedures involving the mandible. Additional mental foramina, called accessory mental foramina (AMF) transmitting branches of mental nerve, have been reported. Detection of AMFs in presurgical imaging may reduce postoperative pain in dental surgical procedures. Aim: The aim of the study was to study the incidence and morphometric analysis of accessory MF in the dry human mandibles of South Indian population. Materials and Methods: Two hundred and sixty dry human mandibles were studied for the presence, location, shape of AMF, and its relation to MF. The horizontal diameter of AMF, and its distance from symphysis menti, the posterior border of mandible and from the base of mandible were measured and statistically analyzed. Results and Conclusions: In our study, AMF were present in 8.85% mandibles (unilateral - 7.6% [4.6% - left, 2.69% - right] and bilateral 1.6%). The most common position was below the second premolar (48.1%). AMF were round in shape (74%) and was often located either superomedial or inferolateral to MF. Their transverse diameter ranged from 0.5 to 1 mm. The AMF were situated at a mean distance of 2.96 mm from MF, 23.47 mm from symphysis menti, 11.24 mm from the lower border of the body of the mandible, and 57.35 mm from the posterior border of ramus of mandible. The knowledge of the presence of AMF and its dimensions would enable the clinicians to do mandibular procedures carefully and avoid injury to the branches of mental nerve that may be passing through it.

Morphological and morphometric analysis of accessory mental foramen in dry human mandibles of south indian population.

Accessory mental foramen (AMF) is a rare anatomical variation. When accessory mental foramen is present, the nerves and vessels that go through the mental foramen (MF) must follow alternative courses and special care must be taken during dental treatment planning. The purpose of this study was to evaluate the occurrence and the location of AMF in a selected Polish population using cone-beam computed tomography (CBCT). Two hundred CBCT (105 males and 95 females) examinations were evaluated for the presence of AMFs. The location and side of AMFs were reported. The mean distance between MF and AMF was also calculated. The vertical size of MF on the side with and without AMF was measured. The obtained variables were statistically analyzed. AMFs were observed in 7% of the patients. There was no statistically significant difference between the appearance of AMF and sex (p > 0.05). We found no significant difference in the vertical size of MF between individuals with and without AMFs (p < 0.05). Twenty-eight AMFs (7%) were observed from 400 sides of 200 patients. AMFs occurred more often in males (18 AMFs) than in females (10 AMFs). Twenty AMFs (71.4%) were located anteriorly, and eight (28.6%) - posteriorly. Fifteen AMFs (53.6%) were on the right side and thirteen (46.4%) - on the left.

/pdf/the-assessment-of-accessory-mental-foramen-in-a-selected-ded9oh7kre.pdf

The assessment of accessory mental foramen in a selected polish population: a CBCT study.

Background. The aim of root canal treatment is to eliminate microorganisms from the root canal system. It consists of removing the infected pulp and shaping root canal system in order to facilitate irrigation and placement of a medicament or permanent filling material. In the last decade, many types of rotary root canal instruments have been introduced, varying in cross-section, blade and pitch design, and taper. Objectives. The purpose of this study was to compare the shaping ability of Hyflex®CMTM Files with ProTaper Next®. Material and Methods. Twenty resin blocks with simulated L-curved canals were used in this experimental study and randomly divided into two groups (ten in each). The canals were prepared with Hyflex CM Files and ProTaper Next to an apical size of 25 according to the recommendations of the manufacturer by crown-down technique. Each instrument was used only once. Before and after preparation blocks were fixed in a constant position and photographed. To investigate the shaping ability of instruments the amount of material removed at the different levels in the root canal, the change of working length and transportation of apex were measured. The results were statistically analyzed using t-test. Results. There was a trend for the ProTaper Next to remove less material from the inner aspects of the canals in apical area when compared with Hyflex CM Files. In the present study, a significantly greater change of working length took place after use of ProTaper Next (p < 0.01). The difference between the average apical transportation in the compared systems was also statistically significant (p < 0.01). Conclusions. Within limitation of this study, both systems prepared canals without significant shaping errors and no instruments fractured. Hyflex CM Files and ProTaper Next maintained artificial curvature well and were safe. Hyflex CM Files are more flexible than ProTaper Next (Dent. Med. Probl. 2015, 52, 1, 54–61).

Comparison of the Shaping Ability of Hyflex® CM™ Files with ProTaper Next® in Simulated L-Curved Canals

Background. Successful root canal treatment is associated with correct canal preparation. The quality of mechanical preparation depends on many factors. Researchers are still looking for the optimal methods and instruments for this purpose. Objectives. The aim of the research project was to analyze the structure and work of mechanical files and the effect of simulated canal preparation with a single curvature. Material and Methods. The study involved the reciprocal files: WaveOne® (Dentsply Maillefer) and Reciproc® (VDW) and the rotary file ProTaper Next® (Dentsply Maillefer). The study used 30 resin blocks (Endo-TrainingBloc®, Dentsply-Maillefer) of the artificial canals with a single curvature (ie. L-type canals). Photographs were taken before and after preparation. Using computer images were imposed on and measurement points set. The amount of material removed was determined as the distance between the measuring point and the wall of the canals after the preparation. Results. The greatest mean changes in the working length were observed in the group Reciproc, the smallest in the group ProTaper Next. The highest average amount of material in all groups was removed from the inner wall of the central part of the canal. The greatest value was achieved in the WaveOne group. The lowest value was obtained in the group Reciproc. The best canal centralization was obtained at 8 mm from the apical foramen, the worst at 5–6 mm. Conclusions. The tested instruments prepare simulated canals in a satisfactory manner, but do not provide optimum results. Therefore, preparing the canals of complex anatomy with a  large file and a  large taper carries the major risk of complications. Comparison of WaveOne, Reciproc and ProTaper Next system based on a sequence of files showed statistically significant differences (Dent. Med. Probl. 2016, 53, 4, 476–482).

/pdf/properties-of-mechanical-endodontic-instruments-and-the-4i7jzu166w.pdf

Properties of Mechanical Endodontic Instruments and the Quality of the Simulated Canal Preparation

Background. Chemomechanical preparation of the root canal system is a key factor in endodontic therapy. It is also important to maintain the integrity and localization of anatomical structures in the apical region of the canal and avoid excessive weakening of the root as a result of errors which occur during preparation. One of the challenges in endodontic treatment is the preparation of canals with high degree of curvature. Nowadays, many nickel-titanium instruments have been introduced, thereby increasing the efficiency and safety of root canal preparation, as compared to stainless steel hand files. Badanie zostało sfinansowane z funduszu statutowego: Zakład Endodoncji UMED 503/2-044-02/503-01. Dent. Med. Probl. 2016, 53, 2, 222–229 DOI: 10.17219/dmp/61326 © Copyright by Wroclaw Medical University and Polish Dental Society

/pdf/comparison-of-three-different-nickel-titanium-endodontic-3lpad3cxc9.pdf

Comparison of Three Different Nickel-Titanium Endodontic Systems in Shaping Simulated L-Shaped Canals

Background. The aim of root canal instrumentation is to remove necrotic or infected pulp, eliminate microorganisms and create a tapered shape with adequate volume to allow effective irrigation and obturation. Nowadays, the nickel-titanium rotary instruments are very popular and important in endodontic therapy. They are indisputably useful when curved canals are prepared. Objectives. The purpose of this study was to compare the shaping ability of ProTaper Universal® with ProTaper Next® files in simulated L-curved canals. Material and Methods. Twenty resin blocks with simulated L-curved canals were used in this experimental study and randomly divided into two groups. Canals were prepared with ProTaper Universal and ProTaper Next to an apical size of 25 according to the recommendations of the manufacturer. Pre-operative and post-operative images were superimposed by GIMP 2.6. The amount of material removed from canal walls (outer and inner), apical transportation and changes of working length were measured and analyzed statistically by t-test. Results. ProTaper Universal removed more material from outer canal walls than ProTaper Next. Loss of working length and transportation towards outer aspect was smaller for L-curved canals which were prepared with ProTaper Next. Dent. Med. Probl. 2014, 51, 3, 336–344 ISSN 1644-387X © Copyright by Wroclaw Medical University and Polish Dental Society Maszynowe opracowanie sztucznych kanałów 337 Celem leczenia kanałowego jest: usunięcie zmienionej chorobowo miazgi, eliminacja mikroorganizmów oraz takie ukształtowanie kanału, które zapewni odpowiednią irygację oraz szczelne i trójwymiarowe wypełnienie [1]. Idealnie opracowany kanał powinien mieć kształt stożka, zwężającego się w kierunku wierzchołka [2]. Procedura kształtowania kanału powinna być wolna od jatrogennych błędów, tj.: złamania narzędzi, formowania stopni czy perforacji [3]. Opracowanie kanałów prostych zwykle nie sprawia dużych problemów. Trudności mogą pojawić się w przypadku obecności krzywizn, podczas opracowywania których dochodzi do prostowania kanałów i zmiany ich oryginalnego przebiegu [4]. W ostatnich latach do opracowania szczególnie są polecane narzędzia wykonane ze stopu niklowo-tytanowego. Dzięki sprężystości oraz pamięci kształtu (shape-memory effect) są one zdolne do utrzymania naturalnego przebiegu kanału z mniejszym ryzykiem powstawania błędów w porównaniu z narzędziami ręcznymi wykonanymi ze stali nierdzewnej [5]. Wprowadzono wiele systemów wykonanych ze stopu niklowo-tytanowego, różniących się między sobą przekrojem, ukształtowaniem powierzchni tnących, budową wierzchołka, a także stożkowatością [6–8]. Narzędzia ProTaper Universal® są systemem maszynowym wykonanym ze stopu niklowo-tytanowego. Podstawowy zestaw obejmuje sześć niklowo-tytanowych narzędzi: trzy „shaper” (Sx, S1 i S2) do opracowania ujścia oraz 2/3 przykoronowej części kanału oraz trzy „finishing” (F1, F2 i F3) do opracowywania 1/3 przywierzchołkowej części kanału. Narzędzia oznaczone barwnymi paskami, różnią się między sobą stożkowatością i rozmiarem przy wierzchołku. Zestaw podstawowy narzędzi ProTaper Universal przedstawia ryc. 1. Pilniki Sx-F2 w przekroju poprzecznym mają kształt wypukłego trójkąta (ryc. 2), natomiast pilnik F3 ma zmodyfikowany przekrój polegający na obecności wyżłobień na powierzchniach pomiędzy krawędziami tnącymi. Modyfikacja ta została wprowadzona w celu zwiększenia jego sprężystości [9] (ryc. 3). Do opracowywania szczególnie szerokich kanałów producent dołączył dwa uzupełniające (F4 oraz F5) o przekroju narzędzia F3. Ważnymi cechami narzędzi ProTaper Universal są: zmienna stożkowatość w obrębie jednego narzędzia oraz zaokrąglony, bezpieczny wierzchołek (rounded safe tip) [10]. Conclusions. ProTaper Next had lower tendency to straighten simulated L-curved canals and maintained the original canal shape most accurately (Dent. Med. Probl. 2014, 51, 3, 336–344).

Michał Łęski

Papers

The assessment of accessory mental foramen in a selected polish population: a CBCT study.

Comparison of the Shaping Ability of Hyflex® CM™ Files with ProTaper Next® in Simulated L-Curved Canals

Properties of Mechanical Endodontic Instruments and the Quality of the Simulated Canal Preparation

Comparison of Three Different Nickel-Titanium Endodontic Systems in Shaping Simulated L-Shaped Canals

Comparison of the Shaping Ability of Two Rotary Files in Simulated L-Curved Canals