Endodontic length measurements using cone beam computed tomography with dedicated or conventional software at different voxel sizes

The aim of this study is to investigate the accuracies and the agreements of the 3D Endo software, conventional CBCT software Romexis Viewer at three voxel sizes, and the EAL ProPex Pixi in endodontic length measurements. Three hundred and twenty-nine root canals in 120 intact human extracted molars were accessed. The actual lengths (AL) and electronic lengths (EL) were measured using the ruler and electronic apex locator (EAL), respectively. Teeth were scanned using the CBCT at different voxel sizes (0.075, 0.10, and 0.15 mm). Root canal lengths were measured using 3D Endo with proposed length (3D-PL) by software, corrected length (3D-CL), Romexis Viewer. The Fisher's exact test, paired t-test and Bland-Altman plots were calculated to detect the agreements of the four methods with AL measurements. The ProPex Pixi measurements obtained the highest accuracy in the range of ± 0.5 mm. There was agreement between the 3D-PL and the 3D-CL with AL measurements at voxel size of 0.15 mm and at voxel size of 0.10 mm, respectively. The CBCT Romexis Viewer measurements agreed with AL at three voxel sizes. The conventional CBCT measurements using Romexis Viewer and dedicated software did not reach to the 100% accuracy in the range of ± 0.5 mm.

Comparison of Four Electronic Apex Locators in Detecting Working Length: An Ex Vivo Study

AIM

To compare the accuracy of four different electronic apex locators (EALs) in detecting a position 0.5 mm short of the major foramen.

MATERIALS AND METHODS

The actual working length of thirty-five extracted human teeth was determined visually as 0.5 mm short of the apical foramen. After actual working length measurements, electronic working length was measured with four different EALs (Apex Pointer+, Raypex 5, Apex ID, and Raypex 6). Measurements were repeated three times by different operators. The data were analyzed using the intraclass correlation coefficient (ICC), the repeated measure analysis of variance (rANOVA) and Bonferroni post hoc tests. The significance level was set at p < 0.05.

RESULTS

The mean differences between electronic and actual working length were-0.305 mm, 0.098 mm, 0.037, and 0.144 mm for the Apex Pointer+, the Raypex 5, the Apex ID, and the Raypex 6, respectively. Multiple paired comparisons (Bonferroni test) also showed the Apex Pointer+ is significantly different from the Raypex 5, Apex ID and Raypex 6 (p = 0.000, p = 0.001, and p = 0.001 respectively).

CONCLUSION

All EALs showed an acceptable determination of the working length between the ranges of ± 0.5mm except for the Apex Pointer+ device, which had the lowest accuracy. Further studies may be beneficial especially to better evaluate the accuracy of the Apex Pointer+.

CLINICAL SIGNIFICANCE

This article shows that Apex ID, which has only recently been introduced into the market, showed an acceptable determination of the working length. Its accuracy was similar to that of Raypex 5 and 6.

Accuracy of CBCT-based root canal length predetermination using new endodontic planning software compared to measurements performed with an electronic apex locator ex vivo

OBJECTIVE

To evaluate the accuracy of the new endodontic planning software (3D Endo Dentsply Sirona) based on cone beam computed tomography (CBCT) to predetermine root canal lengths compared with measurements performed with an electronic apex locator (Raypex 6; VDW) ex vivo.

MATERIALS AND METHODS

CBCT scans of forty extracted human maxillary (n = 20) and mandibular (n = 20) molars were taken, and root canal lengths were predetermined with the 3D Endo software using the apical foramen (AF) and the adjoining cusp as references. Root canal lengths were determined with the Raypex 6 using the same references. To evaluate the accuracy, absolute differences between both methods and the actual root canal length (gold standard) were calculated and statistically analyzed.

RESULTS

Differences between lengths measured with the 3D Endo and the Raypex 6 compared with the gold standard showed no significant differences (P = 0.879). Mean differences were 0.37 mm versus 0.35 mm in the maxillary molars, and 0.30 mm versus 0.31 mm in the mandibular molars. A total of 75.8% (3D Endo) and 79.1% (Raypex 6) of all measurements were within the limits of ± 0.5 mm. Both methods showed a tendency to result in short measurements (P < 0.001).

CONCLUSIONS

Within the limitations of this study, the 3D Endo software enables an accurate three-dimensional (3D) predetermination of root canal lengths.

Precision of multi-frequency electronic apex locators

Data sourcesCochrane Central Register of Controlled Trials, Medline, Embase and Scopus databases.Study selectionStudies that reported the precision of electronic apex locators (EALs) in locating the apical constriction (AC) in primary root canal treatment of human teeth compared with a histologic evaluation of the AC were considered.Data extraction and synthesisData were extracted and quality assessed independently by two reviewers.ResultsTen studies were included, reporting on 1105 EAL measurements. Seven studies were considered to be at high risk of bias and three at low risk. Four different EALs were evaluated; Root ZX (J Morita, Tokyo, Japan), Justy II (Hager & Werken GmbH & Co, Duisburg, Germany), Endy 5000 (Loser Co, Leverkusen, Germany) and Endox (Lysis Co, Milan, Italy). Three EALs, Root ZX, Justy II and Endy 5000 were more accurate than the Endox in determining the distance between the file tip and the apical constriction. Pulp status was only available for 194 (17.55%) of the measurements. The status of the pulp (vital or necrotic) had no significant effect on precision.ConclusionsThe precision of electronic working length measurement depends on the device used and the type of irrigation and is not influenced by the status of the pulp tissue.

Modern Endodontic Principles Part 3: Preparation

The purpose of instrumentation is to facilitate irrigation and allow controlled obturation. This article will revisit methods of instrumentation of the root canal system with consideration given to length determination, apical preparation and the concept of patency filing. It will discuss hand instrumentation and rotary preparation looking at emerging technology such as reciprocating systems and the self-adjusting file. CPD/CLINICAL RELEVANCE: Mechanical preparation of the root canal system is of fundamental importance in achieving success, creating a more easily managed environment from a biological perspective.

Development and Evaluation of an Endodontic Simulation Model for Dental Students

The aims of this study were to develop an endodontic simulation model able to implement the electronic method of working length determination (electronic apex locators, EALs) in a dental school, to evaluate the practicality of this tool for dental students, and to compare the accuracy of working length measurements achieved by the EAL and the radiographic method. A new simulation model was constructed by embedding extracted human teeth in a self-cured resin, along with a conductive medium. After radiographic and electronic working length determinations, root canal instrumentation was performed by students at a dental school in Austria according to the working lengths obtained from the EAL. Subsequently, root apices (n=44) were longitudinally sectioned using a diamond coated bur. Measurements of the distance between the anatomical root apex (ARA) and the apical constriction (AC) as well as between ARA and the ascertained apical point of endodontic instrumentation were performed using digital photography and a 3D computer-assisted design software. The distance between ARA and the radiologic (ARA-R) or electrometric (ARA-EL) readings of the apical point of endodontic instrumentation was compared with the actual distance ARA-AC. The accuracy of both methods was determined. The difference between the actual distance ARA-AC and the targeted radiological distance was statistically significant (p=0.0001), as was the measured distance between ARA-R and ARA-EL (p=0.016). The electronic method seems to be more precisely referring to the AC (R(2)=0.0198) than the radiographic method (R(2)=0.0019). These results suggest that the endodontic simulation model described in this study can be successfully used in preclinical dental education.

Ex vivo comparison of radiographic and electronic root canal length measurements in primary molars

AIM

The aim of the study was to evaluate the accuracy of root canal length measurements of primary teeth using an electronic apex locator (EAL) and digital radiography in comparison to stereomicroscopic measurement as gold standard.

MATERIALS AND METHODS

After preparation of access cavities of twenty extracted primary molars, the teeth were embedded in alginate blocks. Endodontic files were inserted in the root canals and the length was measured using ProPex II (Dentsply, Maillefer). When the reading was stable for 5s a silicone stop was used for reference. The true lengths of the files were then measured using a micrometer. The gold standard was determined by observing the tip of the file at the apical foramen under a stereomicroscope. For radiographic measurements standard images were obtained at 30 cm source-to-object distance, and zero degrees vertical and horizontal angulations. Radiographic images of each experimental tooth were obtained with the Digora Storage Phosphor Plates (SPP) (Soredex, Orion Corporation, Helsinki, Finland) with the x-ray unit operating at 65 kVp and 10 mA for 0.16 seconds (Trophy Radiologie, Vincennes, France). The radiographic root lengths were measured with the measurement tool of the Digora for Windows software. The mean measurements of both methods were compared to the gold standard measurements using Repeated Measure ANOVA test with Bonferroni adjustments to identify the pair-wise differences (p=0.05).

RESULTS

The mean measurements obtained with the EAL (14.06±1.89 mm) were significantly lower than measurements done with SPP images (14.24±1.98 mm) (p<0.05). However, when both root canal length measurement techniques were compared to stereomicroscopic measurements (gold standard), no statistically significant difference was found.

CONCLUSION

The EAL might be safer than digital radiography for the measurement of root canal length in primary teeth.

Appraisal of the difference between the mesiodistal diameters of deciduous incisors and molars and permanent teeth

AIM

Difference in tooth size between deciduous and permanent teeth can resolve space problems during development of the dentition.

AIM

To determine the difference in size between deciduous and permanent teeth in the anterior and posterior areas of the mouth in a group of school-age children from Medellin, Colombia.

DESIGN

this longitudinal prospective, descriptive investigation was carried out in 139 skeletal Class I dental stone casts from school-age children from Medellin. Patients were followed annually from 6 to 12 years of age. The final sample consisted of 53 children (35 girls and 18 boys). Leeway space and the incisor liability were determined.

RESULTS

A higher positive leeway space was found in the mandible than in the maxilla (3.622 mm and 1.556 mm, respectively). Incisor liability was negatively higher in the maxilla than in the mandible (-7.884mm and -5.386mm, respectively). Six patients showed a negative leeway space between -1.582 mm and -3.184 mm for the mandible and the maxilla, respectively. No statistical significant differences were found by gender; girls showed higher leeway space and incisor liability than boys.

CONCLUSION

Normal values for one ethnic group should not be considered normal for another and each group must be treated according to its own characteristics.

Electronic apex locators may be better at determining endodontic working length than radiographs and could reduce patient radiation exposure

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Clinical efficacy of electronic apex locators: Systematic review. Martins JNR, Marques M, Mata A, Carames J.J Endod 2014;40(6):759-77.

REVIEWER

Nicholas Chandler, BDS, MSc, PhD, LDSRCS, MRACDS (Endo), FDSRCPS, FDSRCSEd, FFDRCSI PURPOSE/QUESTION: The authors conducted a systematic review to compare radiographic and electronic methods of determining endodontic working length.

SOURCE OF FUNDING

The authors reported no external funding sources.

TYPE OF STUDY/DESIGN

Systematic review

LEVEL OF EVIDENCE

Level 2: Limited-quality patient-oriented evidence STRENGTH OF THE RECOMMENDATION GRADE: Grade B: Limited-quality patient-oriented evidence.

Influence of tooth length on the accuracy of the Root ZX electronic apical foramen locator: an ex vivo study

OBJECTIVE

Electronic apical foramen locators are now widely used to determine working length. This study was designed to determine whether tooth length influenced the accuracy of the Root ZX device.

MATERIALS AND METHODS

Forty extracted maxillary canine teeth with a length range of 27-29 mm were selected. Access cavities were prepared and coronal flaring of canals performed. The teeth were mounted in self-polymerizing acrylic resin to facilitate horizontal sectioning except for the apical 3-4-mm portion of the root and embedded in alginate as the electronic medium. Electronic measurements were taken at the major foramen, 'zero' reading using the Root ZX and compared with the actual root canal length. The teeth were sectioned 3 mm from the coronal reference point to create a second group with shorter length; these reductions in the length continued six times in all to create seven groups of 40 specimens each. The actual and electronic lengths of specimens in each group were measured. Data were analyzed by Pearson's correlation coefficient.

RESULTS

Identical measurements between the actual and electronic root canal length from the longest to the shortest groups were 12.5%, 10.0%, 20.0%, 27.5%, 37.5%, 35.0% and 45.0%, respectively. There was a mild negative correlation between the precise measurements of the Root ZX and root canal lengths in the seven groups (r = -0.964, p < 0.001).

CONCLUSION

Under the conditions of the study, the Root ZX device was more accurate in shorter teeth compared to longer ones.

The effect of residual calcium hydroxide on the accuracy of a contemporary electronic apex locator

OBJECTIVE

The aim of this study was to evaluate the effect of residual calcium hydroxide [Ca(OH)2] on the accuracy of an electronic apex locator (EAL).

MATERIALS AND METHODS

Working lengths (WLs) of 56 extracted maxillary incisors were determined initially by two different methods. The first method used the 'APEX' reading of the EAL as a reference point, 0.5 mm was subtracted and recorded as WL0. The second method used the '0.5' reading and the score was recorded as WL0.5 without subtraction. The roots were prepared to WL0 and divided randomly into three experimental groups (n = 16) (1 mm in group A, 2 mm in group B and 4 mm in group C) and a control (n = 8). Specimens in all experimental groups were filled with Ca(OH)2 paste. Following its removal, WLs were re-determined with the same methods.

RESULTS

In group C, pre/post WLs were significantly different (p < 0.05). No significant difference was observed between the other experimental groups and the control group.

CONCLUSION

Accuracy of EAL decreased proportionally with the amount of paste remaining at the ±0.5-mm tolerance level. Ca(OH)2 paste remnants may cause incorrect EAL readings.

Accuracy of three different apex locators and visual exam in primary teeth with and without root resorption in vitro

AIM

The aim of this study was to evaluate the accuracy and reliability of three apex locators (EndoMaster, Raypex, DentaPort ZX) and visual assessment in primary molar teeth in vitro.

MATERIALS AND METHODS

Twenty-four extracted human primary molar teeth with and without root resorption were used in this study. After endodontic access preparation, root canal length was visually measured by means of a K file; then the teeth were embedded into alginate and the roots were measured again by mans of the three apex locators. The results were collected in SPSS 15.0 and statistical evaluations were completed by one-way ANOVA and Kruksal-Wallis test.

RESULTS

The measurements closest to the visually determined length were obtained with EndoMaster. No statistically significant differences were found between visual and apex locators lengths (p>0.05).

CONCLUSION

Within the limitations of this study, the use of apex locators would be useful in the endodontic treatment of primary teeth.

Evaluation of potential apex locator induced electrophoresis

INTRODUCTION

In 1890, Breuer applied an electrical field concept to root canals in an attempt at sterilization. Recently, Balson and Dovgan have renewed interest in the use of electricity to aid in canal disinfection. The purpose of this investigation is to determine if the use of the apex locator or apex locator in conjunction with low speed handpiece causes a previously unreported electrophoretic effect.

MATERIALS

Forty low-fat, dried sirloin steak cubes separated into four groups of 10 and immersed in 5.25% sodium hypochlorite for two minutes while connected to 1) an apex locator with no batteries, 2) one with batteries, or an apex locator and low speed handpiece set at either 3) zero or 4) 800 rotations per minute. Samples were dried and percentage of weight loss was calculated. ANOVA and Tukey Multicomparison tests were performed for statistical significance of α ≤ 0.05.

RESULTS

ANOVA test and Tukey Multicomparison tests showed that there was a significant difference (α ≤ 0.05) between the groups. They revealed statistically significant differences between 800 rotations per minute and all other groups. This study showed that there were no significant differences between an apex locator with no batteries, one used with batteries and one used in conjunction with the low speed handpiece at zero rotations per minute. However, it was shown that there was significantly more tissue dissolution with an apex locator with low speed handpiece at 800 rotations per minute compared to the first three groups.

CONCLUSION

These results did not support the original hypothesis that the apex locator with or without the low speed handpiece has an electrophoretic effect. However, the results do support the use of sodium hypochlorite agitation for increased tissue dissolution.

Influence of simulated apical resorption following orthodontic treatment on working length determination: an in vitro study

AIM

External apical root resorption (EARR) is a common complication that may occur during and after orthodontic treatment. In case of need of endodontic therapy for a tooth with EARR, it has not been clarified yet which benefits can be derived by the use of electronic apex locators (EALs). The present study aimed to assess the accuracy of EALs on extracted teeth before and after simulation of EARR subsequent to orthodontic treatment.

MATERIALS AND METHODS

Standard access cavities were prepared on 64 single-rooted teeth. After working length (CWL) determination, specimens were embedded in an alginate mass, connected to two EALs (Apit, Osada, Tokyo, Japan; Root ZX, Morita Corp., Tokyo, Japan) and the electronic working length (EWL) was measured. The apical portion of the specimens was then modified to simulate EARR, and the EWL was determined again. The discrepancy between CWL and EWL was regarded as statistical unit. Collected data underwent statistical analysis by means of non-parametric tests (p < 0.05).

RESULTS

Within a range of ± 0.5 and ± 1.0 mm from CWL, the accuracies were 79.7% and 98.4% (Apit/intact tooth); 82.8% and 96.9% (Apit/simulated EARR); 81.3% and 98.4% (Root ZX/intact tooth); 76.6% and 96.9% (Root ZX/simulated EARR). No statistically significant differences in relation to device or apical condition emerged (p > 0.05).

CONCLUSION

The two considered EALs showed similar accuracy, which was not affected by the EARR simulation. The use of EALs in the treatment of teeth with EARR following orthodontic treatment may be useful.

Three-dimensional tooth crown size symmetry in cleft lip and cleft palate

OBJECTIVE

To evaluate and compare three-dimensional tooth size symmetry in the right and left sides of upper and lower dental arches in cleft lip and palate (CLP) patients and to compare it with an Angle Class I normal occlusion control group.

MATERIALS AND METHODS

Dental casts of 72 individuals with CLP (20 bilateral [BCLP], 34 unilateral left [ULCLP], and 18 unilateral right [URCLP]) and 53 individuals with Class I occlusion, all with permanent dentition, were randomly selected. Mesiodistal (MD), labiolingual (LL), and occlusogingival (OG) measurements of upper and lower teeth were recorded with a digital caliper. Descriptive statistics and paired t-test were used for statistical analysis.

RESULTS

Significant asymmetries were found between the right and left sides of the dental arches in CLP as follows: MD dimension: mandibular first premolar (ULCLP, P < .01); LL dimension: mandibular first premolar (URCLP, P < .05); OG dimension: maxillary central incisor and first premolar (ULCLP, P < .05 and P < .01, respectively), central incisor (BLCLP, P < .01), mandibular canine and first premolar (ULCLP, P < .01), and first molar (ULCLP, P < .05). Tooth crown size asymmetries were also recorded in the Class I group.

CONCLUSIONS

Significant three-dimensional tooth size asymmetries were found in CLP subjects; however, such asymmetries were also present on the Class I control group.

Examination of Bolton Index comparing the traditional method with a 2-dimensional digital measurement method

Index is one of the most important analyses in orthodontic treatment planning. It shows if there is a correct proportion in size between the maxillary and mandibular teeth. In this study we compared the digital and traditional method.

METHODS

35 dental casts were measured using a Vernier caliper. The mean value was compared with the measurements from the scanned images of the dental casts.

RESULTS

The results showed that the digital method provided similar results with those of the traditional one with a mean difference of 0.23 mm. The Pearson correlation coefficients were very high and similar to each other: R = 0.989 and R = 0.988 for the Anterior Bolton Index (ABI) and Overall Bolton Index (OBI), respectively. No statistically significant differences were present from either the ANOVA or the paired t-tests.

CONCLUSION

The used digital method is as accurate as the traditional one, it is faster and easier to carry out and it offers all the advantages of image storage and data for subsequent use.

The evidence supporting methods of tooth width measurement: Part I. Vernier calipers to stereophotogrammetry

Measuring tooth widths is a key component of orthodontic treatment planning. Over recent decades, many methods have been proposed to achieve this purpose. The current review highlights and describes the initial techniques. The evidence behind their use is presented along with a brief discussion of their benefits and shortfalls. With knowledge and understanding of the accuracy and limitations of the various measurement methods, the clinician may be better informed and therefore able to select the most appropriate method for clinical practice.

An in vivo evaluation of different methods of working length determination

OBJECTIVE

The purpose of this in vivo study was to compare the ability of digital tactile, digital radiographic and electronic methods to determine reliability in locating the apical constriction.

MATERIALS AND METHODS

Informed consent was obtained from patients scheduled for orthodontic extraction. The teeth were anesthetized, isolated and accessed. The canals were negotiated, pulp chamber and canals were irrigated and pulp was extirpated. The working length was then evaluated for each canal by digital tactile sensation, an electronic apex locator (The Root ZX) and digital radiography. The readings were then compared with post-extraction working length measurements.

RESULTS

The percentage accuracy indicated that EAL method (Root ZX) shows maximum accuracy, i.e. 99.85% and digital tactile and digital radiographic method (DDR) showed 98.20 and 97.90% accuracy respectively.

CLINICAL SIGNIFICANCE

Hence, it can be concluded that the EAL method (Root ZX) produced most reliable results for determining the accurate working length.

Teaching model for artificial teeth and endodontic apex locators

Artificial teeth are a useful teaching aid during endodontic education. This article describes the development of a simple and inexpensive model that can be equipped with artificial teeth. It shows that working length determination in artificial root canals using electronic apex locators is possible and that the embedding media has no influence on measurements. The model supports the application of current endodontic techniques and facilitates a validated evaluation of the treatments between students. Artificial teeth can be removed for visualization and replaced for further endodontic exercises.

An in vitro comparison of working length determination by two motor-driven electronic apex locators

AIM

The aim of this study was to evaluate the in vitro working length determination of two different apex locator integrated endodontic motors during mechanical preparation.

METHODS

A total of 51 maxillary incisors were selected. The access cavities were prepared. The actual working lengths (AWL) were predetermined with a #15 stainless steel file. Specimens were then mounted in an alginate model.

RESULTS

Working lengths recorded were VDW Gold (V1), Tri Auto ZX (T1) without using electronic motor and VDW Gold (V2), Tri Auto ZX (T2) by using apex locators in electronic motor operation mode. Data was analyzed by repeated measurements of ANOVA (α=0.01). No difference was found between V1, V2, T1 and T2 (P>0.01). However, statistical analysis found significant differences between AWL and other groups (P<0.01).

CONCLUSION

As the values obtained in motor driven mode are equivalent to manual mode measurements, both devices can be safely used without disruption of working length.

Root canal length determination by different methods in primary teeth: an in vivo study

PURPOSE

To evaluate and compare the accuracy of root canal lengths (RCLs) in primary teeth using different clinical methods.

METHODS

RCLs of 70 extracted human primary single-rooted teeth were estimated in vivo by a calibrated investigator using the electronic apex locator (EAL) method, radiovisiography (RVG), conventional radiography (X-ray), and tactile sensation method (TSM). The teeth were categorized into Group 1 (G1; teeth without physiological root resorption [PRR]); Group 2 (G2; teeth with one-fourth apical PRR); and Group 3 (G3; teeth with one-fourth to three-fourths lingual PRR). RCLs determined by various in vivo methods were compared with the ex vivo actual root canal length method (ARCL), as determined by stereo-microscope. Data obtained were compared using analysis of variance, Newman-Keuls test, and Student's test.

RESULTS

In Groups 1 and 2, the mean RCL determined by EAL was closest to that of the gold standard ARCL, followed by RVG, X-ray, and TSM. In G3, the mean RCL determined by EAL was closest to ARCL, followed by TSM, RVG, and X-ray.

CONCLUSION

A fifth-generation electronic apex locator was found to be useful in accurately determining root canal lengths of primary teeth with or without physiological root resorption.

Evaluate the usage of different advanced endodontic instruments and techniques in pediatric dentistry

OBJECTIVE

The purpose of study is to find the prevalence of usage of different advanced endodontic instruments and techniques in pediatric dentistry.

MATERIALS AND METHODS

A self-administered, structured questionnaire written in English validated through a pretested survey was randomly mailed to the postgraduate students in different dental colleges. A total of 182 of the complete filled questionnaires were returned with response rate of 68.2%. The data were analyzed using the SPSS version 15.0. The Student's t-test and ANOVA test were used as test of significance. Karl Pearson's correlation test was used to assess years of education and usage of endodontic instruments.

RESULTS

There was a limited use of new endodontic technologies in the present study. The highest positive response to the usage of advanced endodontic instruments was related to NiTi rotary files with highest number seen among 3rd year students. A linear relationship was found between years of postgraduation and usage of advanced endodontic instruments using Karl Pearson's correlation coefficient.

CLINICAL SIGNIFICANCE

Based on the results of the present study, it seems that the usage of advanced endodontic instruments is not up to the level. Also we found increased use of new technologies with years of postgraduation.

New multipurpose endodontic device developed in Germany for use in predoctoral and continuing dental education and science

The purpose of this article is to describe a simple and versatile aid for the endodontic treatment of extracted teeth and its possible applications. The Med*-box is a new endodontic multipurpose device made of transparent acrylic that permits all elements of root canal treatment to be performed and evaluated either visually or radiologically. The Med*-box represents a valuable addition to the spectrum of educational and practical means in endodontic training. It is well suited for students, dentists, and endodontists for learning the handling of new materials, methods, and instruments in endodontics before they work clinically upon a patient. Also in the context of scientific endodontic issues, the Med*-box represents a simple, economical, and easily manageable aid.

A comparison between two fourth generation apex locators

AIM

The aim of this study was to evaluate ex vivo the accuracy of two fourth generation apex locators and compare the measurements obtained.

METHODS

Forty single and multiroots of permanent teeth (i.e., sixty-two canals) without caries or restorations were selected. After determining the real canal length using a stereomicroscope and a digital calliper, we evaluated the accuracy of two fourth generation electronic apex locators (the Bingo 1020 and the Propex) by means of an experimental study model and an endodontic simulator. The experimental model uses a digital comparator to determine the root canal length to a precision of 0.001 mm, while the endodontic simulator replicates the normal clinical condition. The difference between the real length of each canal and that obtained with the two study models was calculated.

RESULTS

In both experiments, the Bingo 1020 expressed a 94.35% and the Propex expressed a mean accuracy of 90.31% in positioning the file at ± 0.5 mm.

CONCLUSION

The Bingo 1020 and the Propex apex locators are equally accurate and provide reliable measurements in calculating root canal length.

Root canal shaping using rotary nickel-titanium files in preclinical dental education in Turkey

The purposes of this study were to evaluate the ability of a group of third-year dental students without any endodontic clinical experience to use the ProTaper Instruments (Dentsply Maillefer) to decrease the amount of straightening of curved canals on human molar teeth and to determine the incidence of instrument fractures and instrumentation time. Thirty-one undergraduate dental students in Turkey received a training session. The students prepared a total of 144 root canals in human mandibular or maxillary molar teeth with ProTaper. Fifty-six teeth were excluded due to unreadable image, misinformation, or straight or severe curve. Using pre- and post-preparation digital radiographs, the straightening of curved root canals was investigated. Loss of working length and incidence of fracture were also noted. A total of eighty-eight curved root canals were selected. Mesiobuccal or mesiolingual roots with curvatures of between 20° and 43° as assessed by Schneider's method and working length of between 15 mm and 22.5 mm were included in the study. The means of the curved root canals before and after the instrumentation were 29.5° ± 6° and 27° ± 6.3°, respectively. The means of the working length before and after the instrumentation were 19 mm ± 2.1 mm and 18.3 mm ± 1.9 mm, respectively. A statistically significant difference between straightening of curved root canals and loss of working length was found between before and after instrumentation (p<0.000). The mean straightening of curved root canals and loss of working length after preparation with the size F1 ProTaper file were 2.5 mm ± 3.6 mm and 0.7 mm ± 0.6 mm, respectively. Only two F1 ProTaper instruments fractured at the apical level. The study concluded that rotary instruments performed adequately with inexperienced operators who received a brief structured training session.

Influence of pulp condition on the accuracy of an electronic foramen locator in posterior teeth: an in vivo study

The aim of this study was to assess, in vivo, the accuracy of the NovApex® electronic foramen locator in determining working length (WL) in vital and necrotic posterior teeth. The NovApex®was used in 144 canals: 35 teeth with vital pulps (68 canals) and 42 teeth with necrotic pulps (76 canals). WL was measured with the NovApex® locator and confirmed using the radiographic method. Differences between electronic and radiographic measurements ranging between 0.0 and 0.4 millimeters were classified as acceptable; differences equal to or greater than 0.5 millimeter were considered unacceptable. Pearson's chi-square test was used to assess the influence of pulp condition on the accuracy of NovApex®(a = 0.05). Regardless of pulp condition, differences between electronic and radiographic WL measurements were acceptable in 73.61% of the canals. No statistically significant differences in accuracy were observed when comparing vital and necrotic canals (p > 0.05). There were 38 unacceptable measurements. In none of these cases was the file tip located beyond the radiographic apex; in 32, it was located short of the NovApex® measurement. Pulp condition had no significant effect on the accuracy of NovApex®.

Applicability of two methods of mixed dentition analysis in a contemporary Indian population sample

AIM

More than 10 years experience in implementing the Tanaka Johnston and Moyers methods has shown that they overestimate the sizes of unerupted canines and premolars when used in populations other than the Caucasian. This study was designed to assess the applicability of the two most commonly used methods of mixed dentition analysis and to attempt to derive a more accurate and precise formula to predict the sizes of the unerupted premolars and canines in a sample of Indian population.

MATERIALS AND METHODS

The sample included 200 study models (100 male, 100 female). Tanaka Johnston's and Moyer's equations were applied to this sample and the mean differences between the actual and estimated tooth widths were determined. New regression equations were derived using lower first molars and incisors as the predictors.

RESULTS

The mean difference between the actual and estimated values of canines and premolars using Tanaka Johnston's and Moyers methods were clinically and statistically significant. Therefore new regression equations were derived taking lower first molars and incisors as the predictors for both sexes. On validation, these equations were found to be accurate and precise for this population.

CONCLUSION

It is recommended to use these equations as a method of mixed dentition analysis for the Indian population.

Effects of simulated lateral canals on the accuracy of measurements by an electronic apex locator

BACKGROUND

Accurate determination of the apical terminus plays a significant role in the success of root canal therapy, but accuracy may be affected by the presence of accessory canals.

OBJECTIVE

To evaluate the accuracy of a ratio-based electronic apex locator for roots with simulated lateral canals.

METHODS

Forty-two single-rooted human teeth were randomly divided into 2 groups. For each tooth, the root canal was prepared to the visually determined working length, and the working length was then measured with the Justy II electronic apex locator. Simulated lateral canals (of 2 different diameters) were then prepared at 3 mm (group A) or 6 mm (group B), and the working lengths were measured again with the same instrument. The measurements were analyzed by one-way analysis of variance.

RESULTS

For both groups, there were no significant changes in working length after the creation of simulated canals (p > 0.05).

CONCLUSION

Measurements obtained with the ratio-based electronic apex locator were not affected by the preparation of simulated lateral canals, and the instrument was able to accurately determine the location of the tooth apex.

Repetitive coronal polishing yields minimal enamel loss

PURPOSE

The American Dental Hygienists' Association recommends selective polishing because of risk of enamel removal and lack of documented therapeutic value. The initial study documenting enamel loss from polishing used methods not acceptable for clinical use, while results from other studies are inconsistent. This study examines the effect of simulated life-time polishing on enamel thickness. Enamel loss from polishing is compared to the enamel thickness just coronal to the cementoenamel junction (CEJ) to relate results to clinical application.

METHODS

Eight premolars and 18 molars were polished 150 times with coarse prophy paste, then pre- and post-polishing micrometer measurements were compared. Eight unpolished premolars and 18 unpolished molars were used as control groups. Average enamel thickness from 10 premolars and 10 molars just coronal to the CEJ was chosen to represent minimal enamel thickness, and was calculated using digital radiography. T-tests were used to compare group means.

RESULTS

The mean measurement difference was significantly higher for the premolar treatment group than the control group, but no difference was noted between molar treatment and control groups. Neither treatment group demonstrated significant abrasion when compared to average minimal enamel thickness. Root abrasion was noted on 5 molars.

CONCLUSION

The results of our study indicate that polishing may remove enamel, but the quantity removed is unlikely to be clinically relevant. Root surface abrasion seen on molars is disturbing, considering stain often occurs on exposed mandibular anterior root surfaces and may cause repeated and prolonged polishing. Further investigation into alternative stain removal methods is recommended.

Biologic rationale of esthetic crown lengthening using innovative proportion gauges

Research shows that practitioners tend to underestimate the amount of tooth structure that must be exposed during a crown lengthening procedure. In the anterior portion of the mouth, this can lead to biologic width problems and subsequent cosmetic issues. This paper presents a biologically based, step-by-step approach to periodontal esthetic crown lengthening. Using a series of innovative measuring gauges, the ideal clinical crown length of a tooth as well as the proper occlusogingival placement of the interproximal papilla will be determined based on established, documented tooth proportion relationships. The biologic crown length of the tooth, defined as the distance from the incisal edge to the bone crest, will subsequently be determined as a function of the clinical crown length, with the ultimate goals being adequate tooth structure for the placement of a restorative margin, establishment of a healthy dentogingival complex, and the placement of an esthetically pleasing definitive restoration.

A study on the practical applicability of the rule of golden rectangle in dental aesthetics

Maxillary central incisors are of critical value in the aesthetics of a smile. The Golden Rectangle ratio concept may play an important role in selecting the optimum width and length of this tooth. The aim of the study was to investigate the existence of this ratio among individuals with natural dentition and to validate its role in aesthetic oral rehabilitation. The clinical crown length of the maxillary left central incisor (CI) and combined crown width of the maxillary left and right CI of 70 subjects were measured. The crown width to crown length ratio was calculated and compared with the Golden Rectangle ratio and statistically analysed. Eighty percent of the subjects varied within 2 standard deviations of the ratio of 1.618. No statistically significant influence of gender on the ratio was observed. Golden rectangle was found to have a significant relationship with aesthetic appearance of maxillary central incisors.

Assessment of the reliability of root angulations on panoramic radiographs

AIM

To check the reliability of panoramic radiographs in assessing mesiodistal angulations while considering the true long axes of teeth in relation to a horizontal reference archwire.

METHOD

A clear anatomical typodont with removable teeth was used with 0.8-mm chromium steel balls glued over the incisal/occlusal and apical/furcal portions of teeth to serve as reference markers for representing true long axes of teeth on radiographs and photographs. A photograph of each tooth was taken with a particular technique to serve as a medium through which to measure true mesiodistal angulations of teeth.

RESULTS

Only overall maxillary teeth angulations significantly correlated to true mesiodistal angulations. Radiographic relationship of the long axes of adjacent teeth (convergence or divergence) in the mandibular as well as the maxillary arch did not show any significant correlation to true degree of convergence or divergence and displayed a tendency to accentuate the maxillary canine to premolar divergence and mandibular lateral incisor to canine convergence.

CONCLUSION

Panoramic radiographs provide a poor representation of the mesiodistal angulations of teeth and require cautious use with clinical judgment and adjunctive procedures to ascertain root angulations.

Regression equations for predicting the size of unerupted canines and premolars in an Iranian population: a pilot study

AIM

The aim of this pilot study was to evaluate equations for predicting the size of unerupted canines and premolars during the mixed dentition period in an Iranian population.

METHODS AND MATERIALS

This cross-sectional analysis was performed on 106 subjects (52 girls, 54 boys, aged 13-15 years). Data were obtained from dental cast by making direct measurements of the maximum mesiodistal widths of all mandibular and maxillary incisors, canines, premolars, and first molars with an electronic digital sliding caliper, with an accuracy of ± 0.02 mm and repeatability of ± 0.01 mm. The results were statistically analyzed using Student t tests, Pearson product-moment coefficients, and ANOVA tests. Correlation coefficients (r) and error variance of estimates were determined using a significance level of p<0.05.

RESULTS

No significant differences were found between the mesiodistal tooth widths of males and females in this Iranian population. The highest correlation was between the sum of the mesiodistal width of canines and premolars in the maxilla with the mesiodistal width of the mandibular first molars and maxillary central incisors (r = 0.742). A moderate correlation was obtained in the mandible (r = 0.665). Approximations were developed to predict the size of the unerupted canines and premolars in both jaws (in the maxilla, Y = 0.740X + 14.271, or the simplified formula, Y = 3/4X + 14; for the mandibular arch, Y = 0.658X + 16.353, or the simplified formula, Y = 2/3 X + 16).

CONCLUSION

The strongest correlation was found for the sum of the mesiodistal width of canines and premolars in the maxilla with the mesiodistal width of the mandibular first molars and maxillary central incisors in the maxillary analysis (r = 0.742). A moderate correlation was found in the mandible for the sum of the mesiodistal width of canines and premolars with the mesiodistal width of the mandibular first molars and maxillary central incisors (r = 0.665).

CLINICAL SIGNIFICANCE

The simplified equations proposed for the maxillary arch (Y = 3/4 X + 14) and for the mandibular arch (Y = 2/3 X + 16) offer an easy and practical way to predict the size of unerupted canines and premolars in the maxillary and mandibular arches of Iranian children.

Comparison between the dimensions of lateral incisor crowns adjacent to unerupted palatally displaced and nondisplaced canine

AIM

To compare the dimensions of lateral incisor crowns adjacent to unerupted palatally displaced and nondisplaced permanent maxillary canines.

METHODS

The sample consisted of 36 children between 10 and 12 years of age with unerupted maxillary canines. Each presented with a unilaterally palatally displaced (with respect to the lateral incisor) canine. The lateral incisor next to the palatally displaced canine was considered the experimental tooth; the tooth on the contralateral side was considered the control tooth. Measurements were crown width (mesiodistal), thickness (labiopalatal), taper (convergence of the crown toward the incisal edge), taper type, and crown length.

RESULTS

No association was found between the experimental and control lateral incisors for crown width and thickness. However, a significant correlation was found for crown taper (P=.048) and length (P=.01). The experimental lateral incisors had a higher mean crown taper (0.54 mm) than the controls (0.24 mm). The mean crown length was smaller for the experimental lateral incisors (6.74 mm) than the control ones (7.55 mm).

CONCLUSION

There is a significantly greater possibility of finding lateral incisors with greater crown taper and shorter length next to palatally displaced canines. However, there is no significant difference in crown width or thickness.

Influence of preflaring on the accuracy of length determination with four electronic apex locators

INTRODUCTION

The aim of this study was to compare the influence of preflaring on the accuracy of 4 electronic apex locators (EALs): Root ZX, Elements Diagnostic Unit and Apex Locator, Mini Apex Locator, and Apex DSP.

METHODS

Forty extracted teeth were preflared by using S1 and SX ProTaper instruments. The working length was established by reducing 1mm from the total length (TL). The ability of the EALs to detect precise (-1mm from TL) and acceptable (-1+/-0.5 mm from TL) measurements in unflared and preflared canals was determined.

RESULTS

The precise and acceptable (P/A) readings in unflared canals for Root ZX, Elements Diagnostic Unit and Apex Locator, Mini Apex, and Apex DSP were 50%/97.5%, 47.5%/95%, 50%/97.5%, and 45%/ 67.5%, respectively. For preflared canals, the readings were 75%/97.5%, 55%/95%, 75%/97.5%, and 60%/87.5%, respectively. For precise criteria, the preflared procedure increased the percentage of accurate electronic readings for the Root ZX and the Mini Apex Locator (P < .05). For acceptable criteria, no differences were found among Root ZX, Elements Diagnostic Unit and Apex Locator, and Mini Apex Locator (P > .05). Fisher test indicated the lower accuracy for Apex DSP (P < .05).

CONCLUSIONS

The Root ZX and the Mini Apex Locator devices increased significantly the precision to determine the real working length after the preflaring procedure. All the EALs showed an acceptable determination of the working length between the ranges of+/-0.5mm except for the Apex DSP device, which had the lowest accuracy.

Validity, reliability and reproducibility of three methods used to measure tooth widths for bolton analyses

BACKGROUND

Vernier calipers have traditionally been used as the 'gold-standard' for tooth width measurements. New digital methods may prove to be as valid, reliable and reproducible as caliper measurements.

AIMS

To determine the validity, reliability and reproducibility of mesiodistal crown measurements made with calipers, using the DigiModel method and on digital photographs, and to determine the validity, reliability and reproducibility when the measurements are employed in Bolton tooth size analyses.

METHODS

Twenty-five consecutive study models were used. The maximum mesiodistal crown widths of 12 teeth in each arch (first molar to first molar) were measured with digital calipers, using the DigiModel software (OrthoProof, Caulfield South, Victoria, Australia) and on standardised digital photographs of the models by eight examiners. One examiner measured all models three times using the three measurement methods, two examiners measured all models once using the three measurement methods and five examiners measured all models once using the calipers only. Validity for the widths of individual teeth, the mean tooth width and the Bolton ratios were assessed using a general linear model two-way analysis of variance and pair-wise comparisons between the two digital methods and the calipers. Reliability was assessed with Cronbach's alpha and reproducibility with the intra-class correlation coefficient.

RESULTS

There were statistically significant differences between the tooth widths measured with DigiModel and the calipers (p < 0.001) and with the calipers and digital photographs (p < 0.001). However these discrepancies were judged not to be clinically significant. The Cronbach's alpha scores for all methods were classified as 'excellent'. The intra-class correlation coefficient values exceeded 0.75 for the digital calipers, 0.79 for DigiModel and 0.54 for the digital photographs.

CONCLUSIONS

The validities of DigiModel and digital photographs for tooth width measurements and Bolton analyses are clinically acceptable. The reliability of both methods is also excellent. However, DigiModel software provided more accurate Bolton's ratios and demonstrated greater reproducibility than the digital photographs.

Ex vivo accuracy of an apex locator using digital signal processing in primary teeth

PURPOSE

The purpose of this study was to evaluate ex vivo the accuracy an electronic apex locator during root canal length determination in primary molars.

METHODS

One calibrated examiner determined the root canal length in 15 primary molars (total=34 root canals) with different stages of root resorption. Root canal length was measured both visually with the placement of a K-file 1 mm short of the apical foramen or the apical resorption bevel, and electronically using an electronic apex locator (Digital Signal Processing). Data were analyzed statistically using the intraclass correlation (ICC) test.

RESULTS

Comparing the actual and electronic root canal length measurements in the primary teeth showed a high correlation (ICC=0.95).

CONCLUSIONS

The Digital Signal Processing apex locator is useful and accurate for apex foramen location during root canal length measurement in primary molars.

In vitro comparative study of conventional radiography and Root ZX apex locator in determining root canal working length

Success in endodontic treatment depends on various factors. One of the most important is appropriate preparation of the root canal system, in addition to keeping the periapical region intact as much as possible. This is achieved by determining the penetration depth of the instruments into the canal or the "working" length. Several methods are introduced for working-length determination. The most popular techniques are radiography and electronic apex locators. One type of apex locator is the Root ZX. The purpose of this study was to compare the accuracy of the Root ZX in vitro with conventional radiography.

The accuracy of a 3-D laser scanner for crown width measurements

BACKGROUND

Virtual dental casts have been recently introduced to orthodontics. The problem of capturing the shapes of teeth on study casts may be complicated by the presence of undercut areas and deep grooves.

AIMS

This study aimed to develop a 3-D laser scanner and associated software, and to evaluate the reproducibility and validity of mesiodistal crown width measurements based on slice distinction.

METHODS

To evaluate reproducibility: a cube was scanned with readily available equipment and the digital measurements compared to caliper measurements of the cube; and the mesiodistal widths of artificial upper teeth were measured, set-up in a dental model, scanned, measured on the virtual study models and compared with the reference measurements. Custom software was used to capture and process the resulting images. To determine validity artificial teeth were measured with calipers, set-up in 20 different malocclusions, duplicated and scanned. The caliper measurements of groups of teeth (incisors, canines, premolars, molars) were compared with digital measurements of the same teeth. In the second method to determine validity, 10 dental casts were scanned and measured by two examiners and the mesio-distal widths compared with the reference values, and with each other.

RESULTS

The digital measurements of the cube fell within 0.1 mm of the reference value. The absolute error in repeated measures of the dental model was 0.32 +/- 0.25 mm. The overall correlation between 3-D images of the teeth and the reference values, using the intraclass correlation coefficient (ICC), was 0.84. The most and least valid results for groups of teeth were the premolars and canines, respectively. The inter-observer ICC was 0.60, and each examiner's ICC versus the reference values were 0.833 and 0.855.

CONCLUSIONS

The mesiodistal widths of teeth and groups of teeth can be reliably and validly measured on virtual study models using the scanner and software developed for this purpose. Inaccuracy in the canine region may be overcome by using a smaller rotational angle during scanning.

Creating certainty and confidence with indirect bonding

Indirect bonding offers a superior method of adhering brackets to teeth, but few orthodontists use it. The neglect of this procedure has many origins, including expense, lack of expertise, and inconsistent results. This paper presents an indirect-bonding method that can be used to expedite bonding appointments and make them more pleasant for patients and clinicians alike.