Dental age estimation in Malay children based on all permanent teeth types

The applicability of the Willems et al. model was verified on a collected sample of Malay (Malaysian nationality) children. This sample was split in a reference sample to develop a Malay-specific prediction model based on the Willems et al. method and in a test sample to validate this new developed model. Next, the incorporation of third molars into this model was analyzed. Panoramic radiographs (n?=?1,403) of Malay children aged between 4 and 14.99 years (n?=?702) and subadults aged between 15 and 23.99 years (n?=?701) were collected. The left mandibular seven permanent teeth of the children were scored based on the staging technique described by Demirjian and converted to age using the Willems et al. method. Third molar development of all individuals was staged based on the technique described by Gleiser and Hunt modified by Kohler. Differences between dental age and chronological age were calculated and expressed in mean error (ME), mean absolute error (MAE), and root mean square error (RMSE). The Willems et al. model verified on the collected Malay children overestimated chronological age with a ME around 0.45 year. Small differences in ME, MAE, and RMSE between the verified Malay-specific prediction model and the Willems et al. model were observed. An overall neglected decrease in RMSE was detected adding third molar stages to the developed permanent teeth model.     

New models for age estimation and assessment of their accuracy using developing mandibular third molar teeth in a Thai population

Age estimation using developing third molar teeth is considered an important and accurate technique for both clinical and forensic practices. The aims of this study were to establish population-specific reference data, to develop age prediction models using mandibular third molar development, to test the accuracy of the resulting models, and to find the probability of persons being at the age thresholds of legal relevance in a Thai population. A total of 1867 digital panoramic radiographs of Thai individuals aged between 8 and 23 years was selected to assess dental age. The mandibular third molar development was divided into nine stages. The stages were evaluated and each stage was transformed into a development score. Quadratic regression was employed to develop age prediction models. Our results show that males reached mandibular third molar root formation stages earlier than females. The models revealed a high correlation coefficient for both left and right mandibular third molar teeth in both sexes (R = 0.945 and 0.944 in males, R = 0.922 and 0.923 in females, respectively). Furthermore, the accuracy of the resulting models was tested in randomly selected 374 cases and showed low error values between the predicted dental age and the chronological age for both left and right mandibular third molar teeth in both sexes (−0.13 and −0.17 years in males, 0.01 and 0.03 years in females, respectively). In Thai samples, when the mandibular third molar teeth reached stage H, the probability of the person being over 18 years was 100 % in both sexes.

     

Human age estimation combining third molar and skeletal development

The wide prediction intervals obtained with age estimation methods based on third molar development could be reduced by combining these dental observations with age-related skeletal information. Therefore, on cephalometric radiographs, the most accurate age-estimating skeletal variable and related registration method were searched and added to a regression model, with age as response and third molar stages as explanatory variable. In a pilot set up on a dataset of 496 (283 M; 213 F) cephalometric radiographs, the techniques of Baccetti et al. (2005) (BA), Seedat et al. (2005) (SE), Caldas et al. (2007) and Rai et al. (2008) (RA) were verified. In the main study, data from 460 (208 F, 224 M) individuals in an age range between 3 and 26 years, for which at the same day an orthopantogram and a cephalogram were taken, were collected. On the orthopantomograms, the left third molar development was registered using the scoring system described by Gleiser and Hunt (1955) and modified by Köhler (1994) (GH). On the cephalograms, cervical vertebrae development was registered according to the BA and SE techniques. A regression model, with age as response and the GH scores as explanatory variable, was fitted to the data. Next, information of BA, SE and BA + SE was, respectively, added to this model. From all obtained models, the determination coefficients and the root mean squared errors were calculated. Inclusion of information from cephalograms based on the BA, as well as the SE, technique improved the amount of explained variance in age acquired from panoramic radiographs using the GH technique with 48%. Inclusion of cephalometric BA + SE information marginally improved the previous result (+1%). The RMSE decreased with 1.93, 1.85 and 2.03 years by adding, respectively, BA, SE and BA + SE information to the GH model. The SE technique allows clinically the fastest and easiest registration of the degree of development of the cervical vertebrae. Therefore, the choice of technique to classify cervical vertebrae development in addition to third molar development is preferably the SE technique.     

Application of third molar development and eruption models in estimating dental age in Malay sub-adults

The third molar development (TMD) has been widely utilized as one of the radiographic method for dental age estimation. By using the same radiograph of the same individual, third molar eruption (TME) information can be incorporated to the TMD regression model. This study aims to evaluate the performance of dental age estimation in individual method models and the combined model (TMD and TME) based on the classic regressions of multiple linear and principal component analysis. A sample of 705 digital panoramic radiographs of Malay sub-adults aged between 14.1 and 23.8 years was collected. The techniques described by Gleiser and Hunt (modified by Kohler) and Olze were employed to stage the TMD and TME, respectively. The data was divided to develop three respective models based on the two regressions of multiple linear and principal component analysis. The trained models were then validated on the test sample and the accuracy of age prediction was compared between each model. The coefficient of determination (R²) and root mean square error (RMSE) were calculated. In both genders, adjusted R² yielded an increment in the linear regressions of combined model as compared to the individual models. The overall decrease in RMSE was detected in combined model as compared to TMD (0.03–0.06) and TME (0.2–0.8). In principal component regression, low value of adjusted R² and high RMSE except in male were exhibited in combined model. Dental age estimation is better predicted using combined model in multiple linear regression models.     

Correlation of panoramic radiography and cone beam CT findings in the assessment of the relationship between impacted mandibular third molars and the mandibular canal

Objectives

The aim of this study was to assess the reliability of four panoramic radiographic findings, both individually and in association, in predicting the absence of corticalization between the mandibular canal and the third molar on cone beam CT (CBCT) images.

Methods

The sample consisted of 72 individuals (142 mandibular third molars) who underwent pre-operative radiographic evaluation before extraction of impacted mandibular third molars. On panoramic radiographs, the most common signs of corticalization (darkening of roots, diversion of mandibular canal, narrowing of mandibular canal and interruption of white line) and the presence or absence of corticalization between the mandibular third molar and the mandibular canal on CBCT images were evaluated.

Results

Darkening of roots and interruption of white line associated with the absence of corticalization between the mandibular third molar and the mandibular canal on CBCT images were statistically significant, both as isolated findings (p = 0.0001 and p = 0.0006, respectively) and in association (p = 0.002). No statistically significant association was observed for the other panoramic radiographic findings, either individually or in association (p > 0.05).

Conclusion

Darkening of roots and interruption of white line observed on panoramic radiographs, both as isolated findings and in association, were effective in determining the risk relationship between the tooth roots and the mandibular canal, requiring three-dimensional evaluation of the case.     

Dental age estimation in Somali children using the Willems et al. model

Aim

The aim of the current study was to retrospectively collect dental panoramic radiographs from Somali children living in Finland, to use the radiographic data to develop a new age estimation model based on the model established by Willems et al. (J Forensic Sci 46(4):893–895, 2001), and to compare the age prediction performances of the Willems et al. model (WM) and the newly developed model.

Material and methods

Dental panoramic radiographs from 808 healthy Somalis born in Finland were selected. The development of the seven left mandibular permanent teeth, from the central incisor to the second molar, was staged according to Demirjian et al. (Hum Biol 45(2):211–227, 1973). Radiographs with all listed permanent teeth completely developed were excluded. The studied sample consisted of 635 subjects (311 females, 324 males) ranging in age from 4 to 18 years. Kappa and weighted Kappa statistics were used to quantify intra- and inter-observer agreement in stage allocation. The collected dataset was used to validate the WM, constructed on a Belgian Caucasian reference sample, and to establish a Somali-specific age estimation model (SM) based on the WM. Both models were validated and their age prediction performances quantified using mean error (ME), mean absolute error (MAE) and root mean squared error (RMSE).

Results

The SM resulted in a slight underestimation of age when the sex groups were analysed separately or combined, with ME varying between 0.04 (standard deviation (SD) 1.01) and 0.05 (SD 1.04) years, MAE between 0.77 and 0.80 years and RMSE between 1.01 and 1.04 years. The WM statistically significantly underestimated the age of females, with an ME of 0.20 (SD 1.01) years (p = 0.0006). For males, and for females and males combined, no statistically significant ME was observed.

Conclusion

The WM and SM were similar in their age prediction performances, and the use of the WM in dental age assessment in the Somali population is justified.

     

Radiological age estimation: based on third molar mineralization and eruption in Turkish children and young adults

Radiographic evaluation of mineralization and eruption stages of third molars using dental panoramic radiographies can be an efficient tool for chronological age estimation in both forensic sciences and legal medicine. The third molar tooth is utilized for dental age estimation about the age span of 15–23?years because it represents the only tooth still in development. The aim of this study is to obtain and analyze data regarding third molar development and eruption in Turkish population for dental age estimation. A total of 744 dental panoramic radiographies of 394 female and 350 male subjects aged between 8 and 22?years were examined. Third molar development was determined according to the Nolla classification system, and eruption was assessed relative to the alveolar bone level. Mandibular and maxillary third molars were generally found at similar stages of development on both sides. Nolla stage 6 (completed crown calcification) was reached at around the age of 15 in both maxillary and mandibular third molars in both sexes. Alveolar emergence was at around the age of 16 in males and around age of 17 in females. Although third molars’ eruption shows greater variability than development of third molars, data which were obtained from this study about eruption of these teeth can be supportive to development data for age estimation.     

Computed tomography appearance of mandibular para-radicular third molar radiolucencies

Objectives

Mandibular para-radicular third molar radiolucencies (MPRs) were first described in 2004 by Bohay et al (Bohay RN, Mara TW, Sawula KW, Lapointe HJ. A preliminary radiographic study of mandibular para-radicular third molar radiolucencies. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004; 98: 97–101) as a well-defined oval radiolucency surrounded by a thin sclerotic border located immediately distal to the mandibular third molar roots. Bohay et al''s analysis was undertaken using panoramic radiographs. The purpose of this study was to confirm Bohay et al''s findings on panoramic radiographs and to identify and document the appearance of MPRs on cross-sectional CT.

Methods

Panoramic films and CT images of the lower third molar regions from 143 patients were reviewed.

Results

MPR was identified on panoramic film in 12 patients with a total of 14 MPRs. A number of factors were recorded from panoramic films and CT.

Conclusions

This study confirmed the findings of Bohay et al and concluded that the relative lucent appearance on panoramic radiographs can be explained by the presence of one or a combination of factors: (i) an area of decreased density in trabecular bone, (ii) thinning of the inner surface of the buccal cortex, (iii) thinning of the inner surface of the lingual cortex or (iv) a depression in the external surface of the lingual cortex.     

Clinical evaluation of the effects of radiographic distortion on the position and classification of mandibular third molars

OBJECTIVE: Panoramic radiographs are routinely employed for surgical planning of unerupted third molars. The objective of this study was to evaluate distortions in the position of mandibular third molars on panoramic radiographs. MATERIALS AND METHODS: Panoramic radiographs of 14 patients with indication for extraction of the mandibular third molars were used. Transurgical impressions of the crowns of the teeth to be extracted and adjacent second molars (n=19) were achieved with addition silicone and poured with type IV plaster for comparison of the inclinations of the third molars on the radiographs and study casts. RESULTS: There was a mean difference of -5.37 degrees between the position of the third molar on the panoramic radiograph and on the study cast (standard deviation 1.46, P<0.05, Student's t-test). CONCLUSION: There is distortion in the position of teeth on the panoramic radiograph, which may influence the surgical planning; however, this does not invalidate it as the main tool for diagnosis and surgical planning of mandibular third molars.     

Dental age estimation in Somali children and sub-adults combining permanent teeth and third molar development

Estimation of an individual’s age has important applications in forensics. In young individuals, it often relies on separate evaluations of permanent teeth (PT) and third molars (TM) development. Here, we analysed the age prediction performance of combined information from PT and TM in an unusual sample of healthy Somalis, born and living in Finland. PT development was staged according to Demirjian et al. (Hum Biol, 1973) and TM development according to Köhler et al. (Ann Anat, 1994), using panoramic radiographs from 803 subjects (397 males, 406 females) aged 3–23 years. A sex-specific Bayesian age-estimation model for the multivariate distribution of the stages conditional on age was fitted on PT, TM and PT and TM combined. The age-estimation performances were validated and quantified. The approach combining PT and TM only overestimated age with an ME of − 0.031 years in males and − 0.011 years in females, indicating the best age prediction performance.

     

Comparing the accuracy of panoramic and intraoral radiography in the diagnosis of proximal caries

OBJECTIVES: The purpose of this study was to compare the diagnostic accuracy of panoramic and intraoral radiographic surveys in the diagnosis of proximal caries according to the different dental regions (maxillary and mandibular incisor, canine, premolar and molar). METHODS: In this study, full mouth series and panoramic radiographs of 79 patients were used. The radiographs were evaluated for proximal caries by three observers. The diagnostic accuracy of radiographic surveys for each dental region was assessed by means of receiver operating characteristic (ROC) curve analysis. RESULTS: Full mouth series was the most efficient method in the diagnosis of caries for incisor and canine teeth. However, full mouth series and combination of panoramic plus bitewings had similar diagnostic accuracy for premolar and molar teeth. CONCLUSIONS: Panoramic survey alone was not sufficient for the diagnosis of proximal caries for the entire dentition. The combination of panoramic plus bitewing plus anterior periapical survey exhibited a diagnostic accuracy for proximal caries that was comparable with full mouth series.     

Narrowing of the inferior dental canal in relation to the lower third molars

OBJECTIVES: To assess narrowing of the inferior dental canal in the lower third molar regions using computed tomography (CT) and to determine the value of radiographic markers on rotational panoramic radiographs in assessing the true relationships of the inferior dental canal. METHODS: Patients referred for CT assessment of impacted lower third molars were used in this study. The lower third molars were assessed using CT to determine the position and morphology of the inferior dental canal relative to the roots and the cortical plates. The radiographic markers on rotational panoramic radiographs were correlated with the CT findings when rotational panoramic radiographs were available. RESULTS: The patients referred had 202 lower third molars. Inferior positioning of the inferior dental canal was the most common location on CT. Narrowing of the inferior dental canal was found in relation to the lower third molars in 66.8% of cases. The chance of narrowing of the inferior dental canal as shown using CT increased when at least one of the radiographic markers, superimposition, narrowing, deviation or reduction in density was present on the rotational panoramic radiograph. Deviation of the inferior dental canal on rotational panoramic radiographs was found to be the most significant predictor of narrowing of the inferior dental canal and a close relationship to the roots, as shown in CT. CONCLUSIONS: Narrowing of the inferior dental canal is a common finding when impacted lower third molars are assessed using CT. On rotational panoramic radiographs deviation of the inferior dental canal is the best predictor of narrowing of the inferior dental canal and a close relationship to the roots.     

Measurements of tooth length in panoramic radiographs. 1. The use of indicators.

The aim of this study was to investigate both the actual and the radiographic tooth lengths of the maxillary first molar and second premolar and the mandibular premolars in panoramic radiographs. The actual length of 64 extracted teeth was measured. Steel balls were then attached to the cusp and apex and the teeth embedded in plastic moulds. Each pair of plaster casts with their set of teeth was radiographed with an Orthopantomograph twice at an interval of 1 month. The actual and the radiographic tooth length was measured twice by one observer. The mean tooth length of the molar was shorter than that of the premolars. The mean difference between the repeated measurements of the actual tooth length was small and ranged between 0.47 and 1.16% of the tooth length. The mean difference between repeated measurements of the radiographic tooth length was also small, with a method error of 0.13-0.21 mm. The vertical magnification in panoramic radiography was lower for mandibular premolars (13-15%) than for the maxillary second premolar and first molar (17-28%). The palatal root of the maxillary first molar had the highest vertical magnification (28%). Following the second set of radiographs, the mean difference between the measurements was small, except for the palatal root of the maxillary first molar (P < 0.001). Radiographic measurements of this root should therefore be used with caution. The results for the other roots examined indicate that these could be measured with high reproducibility.     

Age estimation by measuring open apices of lower erupted teeth in 12–16 years olds by radiographic evaluation

The purpose of this study was to estimate chronological age from panoramic radiographs by measuring open apices of seven right or left mandibular teeth in children of South Indian origin. A total of 101 male and female patients aged between 12 and 16 years were selected. The panoramic radiographs of the patient were indirectly digitised. The variables N0, x3, x4, x5, x6, x7 and s were measured using a computer-aided drafting program. Statistical analysis was performed to derive a regression equation for estimation of age. Two variables x3 and x7 contributed significantly to the fit, yielding the following linear regression formula: Age = 16.025?9.445 (x7) + 1.620 (x3). Statistical analysis indicated that the regression equation explained 97.5% of total variance (R² = 0.975). The median of the residuals was ?0.0348 years with an interquartile range (IQR) of 0.2520 years. The derived regression equations from these variables can serve as an invaluable tool in estimating the age of children between 12 and 16 years of South Indian origin.     

The assessment of impacted maxillary canine position with panoramic radiography and cone beam CT

Objective

The aim of this study was to correlate the position of impacted maxillary canines on panoramic radiography with cone beam CT (CBCT) and analyse the labiopalatal position of canines and root resorption of permanent incisors in CBCT according to the mesiodistal position of canines on panoramic radiographs.

Methods

This study was a retrospective radiographic review of 63 patients with 73 impacted maxillary canines. The mesiodistal position of the canine cusp tip was classified by sector location and analysed on 73 impacted canines from 63 panoramic radiographs. The labiopalatal position of the impacted canines and root resorption of permanent incisors were evaluated with CBCT. The sector location on panoramic radiographs was compared with the labiopalatal position of impacted maxillary canines on CBCT. The statistical correlation between panoramic and CBCT findings was examined using the χ² test and the Fisher''s exact test.

Results

Labially impacted canines in CBCT were more frequent in Panoramic Sectors 1, 2 and 3, mid-alveolus impacted canines were more frequent in Sector 4 and palatally impacted canines were more frequent in Sector 5. There was a statistically significant association between the panoramic sectors of the impacted canines and the labiopalatal position of the canines (p < 0.001). Root resorption of permanent incisors showed a significant difference according to sector location (p < 0.001) and was observed in Sectors 3, 4 and 5.

Conclusions

This study suggests that the labiopalatal position of impacted canines and resorption of permanent incisors might be predicted using sector location on panoramic radiography.     

Dental age estimation from the developmental stage of the third molars in Iranian population

A sharp increase in forensic age estimation of living persons has been observed in recent years. However, ethnic populations residing in different countries have been insufficiently analyzed. The aim of this study was to achieve a referral database and regression equations for dental age estimation of unaccompanied minors of Iran nationality. A total of 1200 orthopantomograms were collected from original Iran and equally divided in age categories between 10 and 27 years. On the radiographs, the developmental stage of the third molars was scored applying a Demirjian et al. scoring technique. Inter- and intra-observer reliabilities were tested using kappa statistics. Correlation between the scores of all four wisdom maxillary and mandibular third molars teeth and left/right symmetry were evaluated with spearman correlation coefficient. Student’s t-test on asymmetry was performed and regression formulas were calculated. The present database was the first to assemble third molar developmental scores on radiographs of Iran individuals and provided more appropriate dental age estimation of unaccompanied Iran minors. To enhance the accuracy of forensic age estimates based on third molars mineralization, the use of population-specific standards is recommended.     

Pre-operative radiographic evaluation of lower third molars with computed tomography

OBJECTIVES: To report radiographic findings of examinations with computed tomography (CT) of impacted lower third molars with an intimate relation to the mandibular canal and to investigate how findings of a dark band across the roots of the lower third molar on panoramic views correspond to the CT findings. METHODS: CT images of 90 lower third molars (64 patients, mean age 34.6 years) in which plain radiography was insufficient to allow determination of the precise anatomical relations were reviewed retrospectively. Panoramic views of 88 teeth existed; these images were interpreted independent of the CT examinations with respect to presence of a dark band across the roots. RESULTS: In 31% of the CT images, the course of the mandibular canal was buccal, in 33% lingual, in 26% inferior, and in 10% inter-radicular. The tooth was in contact with the mandibular canal in 94% and with the lingual cortex in 86%. In 23%, grooving of the root by the canal was judged to be present. In 63% of the cases where a dark band across the roots was observed on panoramic radiographs, CT revealed grooving of the root. CONCLUSIONS: Pre-operative CT of lower third molars is motivated in selected cases when plain radiography is inconclusive. The finding of a dark band across the roots on panoramic radiographs is an indicator of grooving of the tooth by the canal and justifies a pre-operative CT examination. The absence of dark bands on panoramic views does not exclude grooving of the roots.     

An assessment of the aggressive potential of radiolucencies related to the mandibular molar teeth

AIM: The purpose of this study was to outline the radiographic appearance of radiolucent lesions related to the molar teeth and to determine which features indicate aggressive lesions. PATIENTS AND METHODS: Panoramic radiographs were reviewed in 66 patients with radiolucencies related to the molar teeth. The radiographic appearances of the lesions were assessed with regard to location and size, and the relationship to the molar teeth. Radiographic evidence of aggression was assessed and pathology reviewed. RESULTS: Nineteen patients had aggressive and 47 had non-aggressive radiolucent lesions. The aggressive lesions included keratocysts, unicystic ameloblastoma, adenoid cystic carcinoma, giant cell granuloma, myxofibroma, chondroblastic osteosarcoma, mestastases and squamous cell carcinoma of the tongue invading the mandible. CONCLUSION: The differential diagnosis of radiolucent lesions in the mandible can be difficult using panoramic radiographs alone. Helpful features in determining aggression were older patients, larger lesions, Lodwick type IC tumour border, condition of the mandibular cortex, movement of adjacent teeth and the relationship of the inferior alveolar canal.     

Ability of two radiographic methods to identify the closeness between the mandibular third molar root and the inferior alveolar canal: a pilot study

Objectives

The aim was to compare the ability of two radiographic methods: the panoramic radiograph (PR) in combination with a 20-degree negative angle periapical radiograph (−20°Pa) vs two periapical radiographs Pa + (−20°Pa), in evaluating the closeness of the lower third molar root and the inferior alveolar canal.

Methods

2 radiographic methods of 32 impacted third molars were used. Two untrained dental students evaluated the closeness of the association between the root tip of the lower third molar and the inferior alveolar canal, both when in contact and separated, using dental cone beam CT as the gold standard. The position of the inferior alveolar canal relative to the third molar root was also recorded. The sensitivities and specificities of these findings were evaluated. Kappa values were used to assess the intra- and interobserver reliability.

Results

Of the 32 teeth, 23 (68.6%) showed contact between the root tip of the third molar and the inferior alveolar canal on dental cone beam CT, and 9 (31.4%) showed separation. The respective mean sensitivities of PR + (−20°Pa) and Pa + (−20°Pa) in detecting contact were 97.9% and 84.8% and the respective mean specificities in detecting separation were 16.7% and 44.4%. Intraobserver agreement in both techniques ranged from 0.69 to 0.94. The respective interobserver reliability was 0.88 in PR + (−20°Pa) and 0.75 in Pa + (−20°Pa).

Conclusions

Both the PR + (−20°Pa) and the periapical vertical tube-shift technique Pa + (−20°Pa) have high potential for detecting the closeness between the third molar root and the inferior alveolar canal.