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At least 919 records · Page 51Linked to original sources
PubMed2005

Determining the apical terminus of root-end resected teeth using three modern apex locators: a comparative ex vivo study.

AIM: To assess ex vivo the accuracy of various electronic apex locators in locating the apical terminus of root-end resected teeth. METHODOLOGY: Ninety extracted human posterior teeth (182 root canals) were prepared to a minimum size of 40 and filled with gutta-percha and sealer. After resection of the apical 3 mm of the root, the root canal filling was removed using HERO rotary instruments. The size of the root canal at the apical terminus after removal of the filling ranged from size 50 to 90. The root canal length to the apical terminus was determined using 3 apex locators (Root ZX, Raypex4 and Apex Pointer). A new mounting model that utilized a micrometer was used to perform the measurements and to visually determine the actual position of the apical terminus. The frequency of locating the apical terminus and the corresponding 95% confidence interval (CI) were calculated. Additionally, the coefficient of repeatability of each apex locator and the limits of inter-operator agreement were determined. RESULTS: All apex locators showed an acceptable repeatability (0.02-0.03 mm coefficient of repeatability) and narrow limits of inter-operator agreement (+0.07 and -0.07 mm). The accuracy of determining the apical terminus within 1 mm in the root canal was as follows: Root ZX 90% (164/182 root-canals) [95%CI: 86-94%], Raypex4 74% (135/182 root-canals) [95%CI: 68-80%], and Apex Pointer 71% (129/182 root canals) [95%CI: 65-77%]. No over-instrumentation resulted when the Root ZX device was used. In contrast, using the Raypex4 or the Apex Pointer device resulted in over-instrumentation in 8 of 182 root canals (4%). CONCLUSIONS: Under the conditions of this study all three apex locators were able to detect the apical terminus of root-end resected teeth with an acceptable range. The Root ZX device was the most accurate without over-instrumentation of the root canals.

Dental Pulp Cavity↗
PubMed2006

An ex vivo evaluation of a new root canal irrigation technique with intracanal aspiration.

AIM: To evaluate the effectiveness of a new root canal irrigation technique with intracanal aspiration in removing the smear layer and to assess irrigant extrusion ex vivo. METHODOLOGY: Thirty-five instrumented canals of extracted human canine teeth that had been resected apically by removing 3 mm of the root tip were divided into one control and four experimental groups of seven teeth each. The roots were fixed in a plastic case and surrounded with normal saline agar coloured with 1% acid red. No irrigation was performed in the control teeth. Each root canal in the experimental groups was irrigated with 9 mL of 14% ethylenediaminetetraacetic acid for 3 min, and then with 6 mL of 6% sodium hypochlorite (NaOCl) for 2 min. In the intracanal aspiration technique, the irrigant was delivered from the tip of an injection needle placed 12 mm from the apical root-end and an aspiration needle that was connected to a Root ZX apex locator placed 2 and 3 mm short of the apical root-end in groups 1 and 2, respectively. In the conventional method, the tip of an injection needle used for delivery of the irrigant and as an active electrode was placed 2 and 3 mm short of the apical root-end in groups 3 and 4, respectively, the tip of the aspiration needle was placed 12 mm from the apical root-end in these groups. The readings of the Root ZX during irrigation were recorded. The cleanliness of the canal was evaluated by scoring smear layer from scanning electron microscopy (SEM) images of the canal. Extrusion of NaOCl was detected by measuring the discoloured area of the agar around the apical root-end. The data obtained were statistically analysed by one-way anova, the Kruskal-Wallis test and Friedman's test. RESULTS: In the SEM study, the canals in groups 1-3 were significantly cleaner than those in the control and group 4 (P < 0.05). The mean Root ZX readings in groups 1-3 were approximately "0.5". The discoloured area in group 3 was significantly larger than the other groups (P < 0.05). CONCLUSIONS: Irrigation using the intracanal aspiration technique allowed more effective removal of the smear layer than that performed by the conventional method in an apically resected canine tooth. The intracanal aspiration technique produced limited extrusion of the irrigant beyond the apical foramen.

Apicoectomy↗
PubMed2006

A simple mounting model for consistent determination of the accuracy and repeatability of apex locators.

AIM: To develop a precise and simple mounting model (MM) for evaluating apex locators and to compare the repeatability of the MM with a conventional visual method (VM). METHODOLOGY: Electronic working length determination was performed in 32 maxillary central incisors using two methods: (i) the MM method and (ii) a conventional VM. The MM utilizes a micrometer to determine the distance travelled by the measuring file during working length determination. In the VM, the length of the measuring file (representing the working length) is determined visually using a caliper and a microscope at 6x magnification. Each measurement was repeated once. The repeatability of each method was evaluated by calculating the coefficient of repeatability. RESULTS: The coefficient of repeatability, which includes 95% of the differences between repeated measurements, was 0.04 mm for MM compared with 0.9 mm for VM. The measurement error of MM was significantly lower than VM (0.02 and 0.4 mm respectively). There was a statistically significant difference between the means of absolute difference in repeated measurements: MM 0.01 mm (95% confidence interval (CI): 0.01; 0.02 mm) compared with VM 0.4 mm (95% CI: 0.3; 0.5 mm). CONCLUSION: The new MM had superior repeatability in comparison with the conventional method where visual interpretation is a source of inaccurate measurement.

Electronics, Medical↗
PubMed2006

Evaluation of the accuracy of three electronic apex locators using glass tubules.

AIM: To evaluate the accuracy of three different electronic apex locators (EALs) using glass tubules. METHODOLOGY: Forty-eight glass tubules with different diameters and an agar model were used to mimic root canals. A size 15 stainless steel K-file was used as the measuring electrode. The Root ZX, Propex and Neosono Ultima EZ were used to measure the tubule length with tubules dry, or filled with 0.9% NaCl, 3% H(2)O(2), 2.5% NaOCl or 17% EDTA. The distance between the real length (RL) and measured length (ML) of the tubules was recorded. The range of RL +/- 0.5 mm and RL +/- 1 mm was used to evaluate the accuracy of the EALs. Results were subject to correlation analysis and Friedman's test. RESULTS: In dry tubules, the accuracy of Root ZX was 75-91.7% for RL +/- 0.5 mm and 100% for RL +/- 1 mm, whilst the measurements of the other two EALs were all within the RL +/- 0.5 mm. No influence from the increase in tubule diameter on the accuracy of all three EALs was observed in dry tubules. In tubules filled with electrolyte, the accuracy of the Root ZX decreased as tubule diameter increased (R(d) > 0, P < 0.05). The RL-ML distance recorded by Propex was inversely related to the tubule diameter (R(d) < 0, P < 0.05). The accuracy of Propex was 75-100% for RL +/- 0.5 mm and 100% for RL +/- 0.5 mm when the tubule diameter was not more than 0.80 mm, but decreased in tubules with diameter over 0.80 mm and filled with 2.5% NaOCl or 17% EDTA. Nearly, all the measurements (except for six tubules) using Neosono Ultima EZ were within 1 mm shorter than RL despite the contents in tubules and the increase of tubule diameter. CONCLUSIONS: The accuracy of the Root ZX decreased as the tubule diameter increased when tubules were filled with electrolytes. The electrolytes in the tubules decreased the accuracy of Propex when the tubule diameter was large. The electrolytes in tubules and tubule diameter had no influence on the accuracy of Neosono Ultima EZ. The Propex and Neosono Ultima EZ were more accurate than the Root ZX under various conditions in this laboratory study.

Chelating Agents↗
PubMed2006

Ex vivo accuracy of three electronic apex locators: Root ZX, Elements Diagnostic Unit and Apex Locator and ProPex.

AIM: To compare ex vivo the accuracy of three electronic apex locators (EALs): Root ZX, Elements Diagnostic Unit and Apex Locator and ProPex. METHODOLOGY: Electronic working length determination was carried out in 40 extracted teeth using an ex vivo model. After access preparation, a first operator determined the reference length (AL) for each tooth under a 30x stereomicroscope using the apical constriction as the apical landmark. All teeth were then measured with each EAL and the results obtained were compared with the corresponding AL. The AL was subtracted from the electronically determined distance. The measurements exceeding the AL were recorded as positive (long) and the measurements short of the AL were recorded as negative. Data were analyzed using the Friedman Test and Tukey multiple range test for nonparametric correlation amongst groups. Statistical significance was considered at P < 0.05. RESULTS: Comparing the differences between measurements obtained with the three EALs and those obtained with the stereomicroscope, the percentage of measurements within +/-0.5 mm of the AL was 97.37% (84.22% within 0.5 mm short of AL) for the Root ZX, 94.28% (88.57% within 0.5 mm short of AL) for the Elements and 100% (35.9% within 0.5 mm short of AL) for the ProPex. The mean difference between the AL and the lengths measured by the Root ZX, the Elements and the ProPex were, respectively, -0.157 +/- 0.228, -0.103 +/- 0.359 and 0.307 +/- 0.271 mm. CONCLUSIONS: The results of the present study confirm that the EALs determined the canal length within +/-0.5 mm from the apical constriction in the majority of cases. The majority of the ProPex readings were long.

Dental Pulp Cavity↗
PubMed2006

The fundamental operating principles of electronic root canal length measurement devices.

It is generally accepted that root canal treatment procedures should be confined within the root canal system. To achieve this objective the canal terminus must be detected accurately during canal preparation and precise control of working length during the process must be maintained. Several techniques have been used for determining the apical canal terminus including electronic methods. However, the fundamental electronic operating principles and classification of the electronic devices used in this method are often unknown and a matter of controversy. The basic assumption with all electronic length measuring devices is that human tissues have certain characteristics that can be modelled by a combination of electrical components. Therefore, by measuring the electrical properties of the model, such as resistance and impedance, it should be possible to detect the canal terminus. The root canal system is surrounded by dentine and cementum that are insulators to electrical current. At the minor apical foramen, however, there is a small hole in which conductive materials within the canal space (tissue, fluid) are electrically connected to the periodontal ligament that is itself a conductor of electric current. Thus, dentine, along with tissue and fluid inside the canal, forms a resistor, the value of which depends on their dimensions, and their inherent resistivity. When an endodontic file penetrates inside the canal and approaches the minor apical foramen, the resistance between the endodontic file and the foramen decreases, because the effective length of the resistive material (dentine, tissue, fluid) decreases. As well as resistive properties, the structure of the tooth root has capacitive characteristics. Therefore, various electronic methods have been developed that use a variety of other principles to detect the canal terminus. Whilst the simplest devices measure resistance, other devices measure impedance using either high frequency, two frequencies, or multiple frequencies. In addition, some systems use low frequency oscillation and/or a voltage gradient method to detect the canal terminus. The aim of this review was to clarify the fundamental operating principles of the different types of electronic systems that claim to measure canal length.

Dental Pulp Cavity↗
PubMed2007

In vivo comparison of working length determination with two electronic apex locators.

AIM: To compare the accuracy of two electronic apex locators (EALs) in the same teeth in vivo. METHODOLOGY: The working lengths in 20 teeth with a single canal were determined with two different EALs (Root ZX; J. Morita Corporation, Tokyo, Japan and Raypex 5 VDW, Munich, Germany) before extraction. When the first EAL was used the files were advanced until the display indicated the 'apical constriction'. The files were then fixed in removable and replaceable light curing composite patterns. The procedure was repeated in the same tooth with the second EAL and a different file. The teeth were then extracted and the apical 4 mm of the root canals were exposed. After that the apical parts with the repositioned files in the canals were digitally photographed under a light microscope. On the images the minor diameter and the major foramen of each sample were marked and the respective distances of the file tips from these positions were measured with a computer program. Subsequently the values of the two groups of EALs were compared using a paired sample t-test. RESULTS: The minor foramen was located within the limits of +/-0.5 mm in 75% of the cases with the Root ZX and in 80% of the cases with Raypex 5. The paired sample t-test showed no significant difference between the EALs regarding determination of the minor foramen. CONCLUSION: The use of EALs is a reliable method for determining working length. The differences between the two EALs were not statistically significant.

Adult↗
PubMed1995

Mixed dentition analysis: a review of methods and their accuracy.

Methods that have been proposed for mixed dentition analysis are reviewed. Prediction of the space required in the dental arch for unerupted permanent canines and premolars has been based either on the correlation between the mesio-distal widths of these teeth and of erupted mandibular incisors, or on measurements of the unerupted teeth on radiographs. Studies comparing the different methods have shown that the method of Hixon & Oldfather (1958), as refined by Staley & Kerber (1980), is the most accurate.

Adolescent↗
PubMed1996

The prevalence of developmental anomalies of teeth and their association with tooth size in the primary and permanent dentitions of 1650 Japanese children.

The prevalence of microdontia, macrodontia, peg-shaped tooth, Carabelli's tubercle, protostylid, paramolar tubercle, central tubercle and palatal accessory cusp were examined in Japanese children. This study included 905 children with primary dentitions (mean age 4 years 7 months) and 745 high-school students with permanent dentitions (mean age 16 years 8 months). Microdontia, macrodontia, Carabelli's tubercle, protostylid and paramolar tubercle were more frequent in the primary dentition, whereas peg-shaped tooth, central tubercle and palatal accessory cusp were more frequent in the permanent dentition. The association between the presence of developmental anomalies and the size of the remaining teeth was significant in permanent dentitions. Both the literature and this study indicate that developmental anomalies of tooth number, size and morphology should be studied as a group rather than as isolates.

Adolescent↗
PubMed1999

Dental maturation in British children: are Demirjian's standards applicable?

OBJECTIVE: The objective of this study was to determine if the standards of dental maturation of Demirjian et al. (1973, 1976) are applicable to British children. DESIGN: The design was cross-sectional, retrospective. SAMPLE AND METHOD: The sample comprised 521 London children of Bangladeshi and white Caucasian (English, Welsh and Scottish) origin aged between 4 and 9 years. Dental age was assessed by crown and root stages of seven mandibular teeth from rotational pantomographs. Dental age was compared to chronological age using a t-test. RESULTS: Differences in dental maturation between the two ethnic groups were not significant. British children as a group were dentally advanced compared to the Canadian standards. The mean (+/- standard deviation) advancement in girls was 0.51 +/- 0.79 years and in boys was 0.73 +/- 0.73 years. CONCLUSIONS: The standards of dental maturation described by Demirjian et al. (1973, 1976) may not be suitable for British children.

Age Determination by Teeth↗
PubMed1999

Delayed development or congenital absence of a single first permanent molar in Japanese child patients.

OBJECTIVE: Delayed eruption of the first permanent molar (M1) is a relatively rare finding. This report describes the occurrence of delayed development and eruption of a single M1 in Japanese child patients. DESIGN: Cases were identified by surveying 353 orthopantomograms taken of child patients attending a Dental Hospital. Dental age, crown morphology and the presence of third permanent molars (M3) were determined from radiographs and clinical examination. SETTING: Osaka University Dental Hospital in Japan. RESULTS: Nine cases were identified from radiographs. The occlusal morphology of the affected molars showed a reduction of the distolingual cusp. Dental ages correlated more closely to chronological ages when the affected teeth were assumed to be second permanent molars (M2) than they did when the teeth were assumed to be M1. M3 proximate to the affected molar was congenitally absent in the orthopantomograms of all affected subjects. CONCLUSIONS: It is suggested that in the cases seen here the affected teeth were likely to have been second permanent molars that had migrated mesially in association with the congenital absence of M1, although congenital absence of M1 has been reported to be extremely rare.

Adolescent↗
PubMed1999

Eruption disturbances of maxillary permanent central incisors associated with anomalous adjacent permanent lateral incisors.

Several causes of eruption disturbances in upper permanent central incisors have been described. This report describes six cases in which the failure of maxillary permanent central incisors to erupt appears to be associated with developmental anomalies in the adjacent permanent lateral incisors. The root formation of the unerupted central incisors was delayed in comparison to the contralateral incisors as was the development of the adjacent lateral incisors. The shapes of the crowns were abnormal and in five cases out of the six described, the primary predecessors of the unerupted incisors were fused.

Child↗
PubMed1999

Incontinentia pigmenti: seven cases with dental manifestations.

Incontinentia Pigmenti (Bloch-Sulzberger syndrome) is an uncommon genodermatosis that usually affects female infants. The condition is characterized by four cutaneous stages and is frequently associated with dental, ocular, central nervous system and structural anomalies. A large case series of seven patients, all female, who presented to the Department of Paediatric Dentistry at the Eastman Dental Hospital over the last 16 years is reported. The dental features of these cases were typical and included missing teeth, microdontia and delayed eruption. In two of the seven cases, both maxillary canines were palatally impacted.

Anodontia↗
PubMed2005

Epidermolysis bullosa and dental developmental age.

OBJECTIVES: The dental development of permanent mandibular teeth in a small group of children with dystrophic epidermolysis bullosa (DEB) was assessed from radiographs and compared to a healthy, age-and-sex-matched control group. METHODS: This was a retrospective radiographic cross-sectional study. The sample consisted of a group of 44 children aged between 4 and 15 years with DEB and healthy, age-and-sex-matched controls. Two quantitative methods of assessing tooth formation were used: (1) a combination of information about tooth length and apex width; and (2) the use of tooth length to predict age. Panoramic radiographs were digitized in order to determine tooth length and apex width. Dental age was calculated, and the difference with real age was tested with Student's t-test. RESULTS: The dentition of both the DEB and control groups was slightly delayed. Using the first method, the delay was 0.34 +/- 0.87 years for the DEB group and 0.29 +/- 0.97 years for the control group. Using the second method, the delay was 0.49 +/- 1.18 years for the DEB group and 0.23 +/- 0.62 years for the control group. This delay was not statistically significant for either method. CONCLUSIONS: The dental formation of permanent mandibular teeth in the group of children with DEB was not significantly different to that found in the control group.

Adolescent↗
PubMed2006

Mixed dentition space analysis in a Jordanian population: comparison of two methods.

AIMS: To test the reliability of the Moyers charts and the Tanaka and Johnston equations in Jordanians and to derive coefficients of correlation between the combined mesiodistal widths of the four permanent mandibular incisors and the combined widths of the canine and premolars of the maxillary and mandibular quadrants. METHODS: The dental models of the dentition of 130 male and 96 female Jordanian subjects (age range is 14-16 years) with complete permanent dentition were randomly selected. The mesiodistal width of the four permanent mandibular incisors, maxillary and mandibular canines, and premolar teeth were measured using a vernier gauge caliper to the nearest 0.1 mm. The actual teeth measurements were then compared with the predicted values derived from the Tanaka and Johnston equations and Moyers probability tables. Correlation and linear regression analyses were performed between the predicted and actual tooth size for Jordanian children and standard regression equations were developed. RESULTS: Except for the maxillary arch in male subjects, Tanaka and Johnston regression equations underestimated the mesiodistal widths of permanent canines and premolars. On the other hand, there were no statistically significant differences between actual mesiodistal widths of canines and premolars and the predicted widths from Moyers charts at the 65% and 75% level for the lower and upper arches in male subjects and at the 85% level for the upper and lower arches in female subjects. For the newly developed regression equations, the correlation coefficients between the sum of the mandibular four incisors and the sum of the canine and premolars were 0.60 (for lower) and 0.51 (for upper) in male subjects and 0.59 and 0.64, respectively, in female subjects. CONCLUSIONS: (1) Tanaka and Johnston prediction method was not accurate when applied to a Jordanian population. (2) Moyers method for prediction can be used for Jordanian children at different probability levels for male and female subjects.

Adolescent↗
PubMed2006

Digital imaging of patterns of dental wear to diagnose bruxism in children.

OBJECTIVE: The aim of this study was to evaluate and compare the area, perimeter, and form (D factor and fractal dimension) of the dental wear among bruxist and nonbruxist children with mixed dentition in order to determine if the dental wear may be used as criteria to diagnose bruxism. METHODS: The children were 8 to 11 years old and were classified as bruxist or nonbruxist, according to anxiety level and temporomandibular disorders. Dental casts of the upper arch were obtained for the bruxist (n = 24) and the control (n = 29) group. The dental wear was measured in digital format and processed automatically. The complete and pathological dental wear was compared between the two groups, using the Student's t-test and Mann-Whitney test. RESULTS: Statistically significant differences were observed between the two groups, with a higher area, perimeter, and more irregular form of the pathological dental wear among the bruxist group. Regarding complete dental wear, differences were only significant for the D factor (an un-dimensional quantitative parameter which produces a relation between the area and the perimeter of an object). CONCLUSION: Digital imaging of dental wear may be used as criteria to diagnose bruxism in children with mixed dentition after making an analysis of the area, perimeter, and irregularity of the form of pathological dental wear.

Anxiety↗
PubMed2007

Anomalies of tooth formation in hypohidrotic ectodermal dysplasia.

OBJECTIVE: The X-linked hypohidrotic ectodermal dysplasia (HED) is the most common type of ectodermal dysplasia. The clinical identification of possible heterozygous females can be difficult because of the varying degrees of clinical signs caused by X-chromosome inactivation. This study is the first to elaborate on anomalies of tooth formation found in a group of hemizygous males and heterozygous females with known ED1 mutations. These tooth anomalies may be used as dental biomarkers for heterozygous females, enabling an earlier diagnosis, and therefore, better treatment and genetic counselling. METHODS: Anomalies of tooth formation were examined using panoramic radiographs, dental casts and oral photographs in hemizygous males and heterozygous females who were identified by molecular genetic analysis. The results were compared to existing controls and normative data. RESULTS: All affected males had multiple missing permanent teeth and tooth malformations. The heterozygous females had a significantly higher frequency of agenesis of permanent teeth compared to normative data. The heterozygous females had an increased prevalence of tooth malformations and reduced tooth size, especially in the mesiodistal dimension. CONCLUSIONS: We conclude that observed anomalies of tooth formation may be used as dental biomarkers in the clinical identification of potentially heterozygous females.

Adolescent↗