Accuracy of radiographs in classification of impacted third molar teeth

doi:10.1016/0278-2391(88)90108-5

Journal of Oral and Maxillofacial Surgery

Volume 46, Issue 8, August 1988, Pages 656-660

https://doi.org/10.1016/0278-2391(88)90108-5 Get rights and content

Abstract

The accuracy of using panoramic radiographs as the basis for classification of impacted third molars and subsequent fee reimbursement by third party carriers was evaluated. Radiographs showing 20 impacted third molar teeth were classified independently by 40 oral and maxillofacial surgeons, 10 general dentists, and 11 health insurance consultants. No group had an accuracy rate better than approximately 50%. These findings demonstrate the unreliability of radiographs for classification of impacted teeth, irrespective of the training or experience of the evaluator.

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Cited by (45)

Three-dimensional image analysis of developing mandibular third molars apices for age estimation: A study using CBCT data enhanced with Mimics & 3-Matics software
2019, Legal Medicine
Three-dimensional imaging has improved the method of analysis in many forensic science investigations. The study aimed to derive regression equation for age estimation by investigating the relationship between chronological age and surface area of the developing mandibular 3rd molars apices. Furthermore, other predictor variables: ethnicity (Malay and Chinese), gender and status of the root development completion (open/closed apices) were also investigated in terms of fit to the age estimation model. One hundred and twenty eight training and 55 validation samples of intact mandibular 3rd molars were selected from 183 CBCT scans. The samples comprised of 93 Malays and 90 Chinese, ranging in age from 13 to 24 years. Three-dimensional image modeling and surface area analysis of the developing mandibular 3rd molars apices were performed using Mimics and 3-Matics software. Multiple linear regression analysis was used to derive age estimation model using chronological age as a dependent variable and surface area of the apices, ethnicity, gender and status of the root development completion (open/closed apices) as predictor variables. A strong inverse correlation (r = 0.95, SD = 1.144) was observed between chronological age and all the predictor variables. The results showed that 89.6% of the variation in age can be explained by the predictor variables. Mean absolute error (MAE) value of 0.8223 was observed when the derived regression equation was tested on the independent validation sample. In conclusion, three-dimensional surface area analysis of the developing mandibular 3rd molars apices can be used as a reliable method for age estimation.
Difficulty of impacted mandibular third molar tooth removal: Predictive ability of senior surgeons and residents
2014, Journal of Oral and Maxillofacial Surgery
Citation Excerpt :
The difficulty of nearly one half of the cases was not correctly estimated during the preoperative evaluation. It has been stated that the surgical difficulty can only be appreciated with certainty during the procedure.17 This might chiefly result from the shortcomings associated with panoramic tomography, the reliability of which in the estimation of surgical difficulty has recently been questioned.
The present study investigated whether residents are able to estimate the degree of difficulty of mandibular third molar removal to the same extent as senior surgeons.
The study included 2 residents and 2 senior surgeons, each of whom extracted 50 mandibular third molars of similar complexity. The clinical variables evaluated included patient age, gender, body size, maximal mouth opening, and tongue interference. The radiographic variables related to the third molars examined on the panoramic radiographs included spatial positioning, tooth–bone interface, root morphology, and proximity of the tooth to the inferior alveolar canal. Before each extraction, the operating surgeon estimated the level of difficulty of the surgery after considering all the variables. The predicted length of time per operation was regarded as representative of operative difficulty. At the end of each operation, its actual duration was also recorded.
The residents and senior surgeons both accurately predicted the difficulty of surgery in just more than one half of the cases. A 57% agreement (κ = 0.24) was found between the senior surgeons' preoperative estimations and actual difficulty, and the agreement was 52% (κ = 0.19) for the residents' estimations. No significant difference was found between the senior surgeons and residents in the accuracy of their estimations of operation length.
The preoperative prediction of the surgical difficulty of mandibular third molar tooth removal was unreliable, not only for the residents, but also for the senior surgeons.
Anatomical differences in lower third molars visualized by 2D and 3D X-ray imaging: Clinical outcomes after extraction
2013, International Journal of Oral and Maxillofacial Surgery
Citation Excerpt :
The radiographic findings associated with IAC exposure include: darkening of roots, interruption of the white line, diversion of the IAC, deflection of the roots, or narrowing of the roots.4 The diagnostic accuracy of panoramic radiographs has been evaluated in several studies.3,11,18–20 Howe and Poyton reported that darkening of the root was the most reliable indication of the relationship between M3 and the IAC.11
The purpose of this study was to evaluate the relationship between third molars and the inferior alveolar canal using panoramic radiographs and cone beam computed tomography (CBCT) scans and to assess clinical outcomes after third molar removal retrospectively. The degree of superimposition, buccolingual position (buccal, central, and lingual) and physical relationship (separation, contact, and involved) were measured using CBCT scanning. Post-extraction complications were recorded. Based on radiographic evaluation, 45.9% of third molar roots were inside the inferior alveolar canal, 21.3% were in contact with the inferior alveolar canal, and 32.8% were separated from the canal. The frequency at which the mandibular canal was separated from the root apex was significantly higher when the canal was in the buccal position (80.0%) than in the central (20.0%) and lingual positions (0.0%). Although on panoramic radiographs all third molars were directly superimposed on the inferior alveolar canal, CBCT showed direct contact or canal involvement in 67.2% and separation of the canal from the root apex in 32.8%. Complications occurred in nine patients: eight had third molar root apices inside or in contact with the inferior alveolar canal. The prevalence of post-extraction complications correlated with the absence of cortication around the inferior alveolar canal.
How often do asymptomatic, disease-free third molars need to be removed?
2012, Journal of Oral and Maxillofacial Surgery
Citation Excerpt :
Based on a panoramic radiograph, OMSs, dentists, and insurance company consultants developed a preplan of the method for surgical removal of the M3s. The accuracy proved to be about 50% in all 3 groups.30 In 1982, Ventä et al31 began a longitudinal follow-up study of M3s in Finland.
The preventive removal of third molars (M3s) should be based on evidence. To optimize the timing of removal of M3s, it is essential to predict the eruption of the tooth and, even more importantly, to recognize beforehand which teeth will become involved in pathologic conditions later in life. The first aim of this review was to determine how well physicians currently can predict the eruption of an M3. The second aim was to review how frequently impacted M3s are removed. The third aim was to summarize the indications for preventive removals as presented in the evidence-based Current Care Guideline for the management of M3s in Finland. The prediction of eruption can be made at accuracies from 80% to 97%. In addition, the decrease in the number of M3s is very rapid, with only 31% remaining at 38 years of age. According to the Current Care Guideline, preventive removals at a young age are justified for 3 groups of teeth in the mandible: partially impacted teeth in the horizontal position, partially erupted teeth in the vertical position, and incomplete roots growing close to the mandibular canal. In conclusion, one fourth of retained and disease-free M3s need to be removed preventively at a young age, whereas the rest should be treated according to signs and symptoms.
Relationships Between Surgical Difficulty and Postoperative Pain in Lower Third Molar Extractions
2007, Journal of Oral and Maxillofacial Surgery
Citation Excerpt :
More recently, Yuasa et al11 proposed a new index taking root anatomy into account. However, some authors believe that surgical difficulty cannot be reliably estimated before surgery on the basis of radiographs but rather must be determined during surgery.21 In our opinion, surgical difficulty is best measured after surgery, and in the present study we used a 4-class scale for postoperative evaluation and also recorded the duration of surgery.
To investigate the influence of surgical difficulty on postoperative pain after extraction of mandibular third molars.
A prospective study was performed of 139 patients who underwent a total of 157 mandibular third molar extractions. For evaluation of surgical difficulty, a 4-class scale was completed after surgery: I, extraction with forceps only; II, extraction requiring osteotomy; III, extraction requiring osteotomy and coronal section; IV, complex extraction (root section). The duration of surgery was also recorded. Postoperative pain was evaluated using a visual analog scale that each patient completed daily until day 6 postsurgery, at which time the sutures were removed.
A statistically significant relationship was observed between surgical difficulty (as rated on the scale) and postoperative pain. Longer interventions generally produced more pain.
Pain after extraction of a mandibular third molar increases with increased surgical difficulty and duration of the intervention.
How well do clinicians estimate third molar extraction difficulty?
2005, Journal of Oral and Maxillofacial Surgery
The goals of this study were to measure surgeons’ abilities to estimate third molar (M3) extraction difficulty and to identify variables associated with errors in estimates of difficulty.
To address our research purpose, we implemented a prospective cohort study and enrolled a sample of surgeons who remove M3s. Predictor variables were categorized as either surgeon or subject specific. The primary outcome variable was the error in estimating operative difficulty. Preoperative and postoperative estimates of difficulty were obtained using a 100-mm visual analogue scale. Error was defined as the difference between preoperative and postoperative estimates of extraction difficulty. Appropriate univariate, bivariate, and multivariate statistics were computed.
The sample was composed of 15 surgeons who operated on 82 subjects having 250 M3s (53.2% mandibular) extracted. The mean level of surgical experience was 8.8 ± 11.1 years. The mean age of the subjects was 26.2 ± 10.7 years; 57.3% were female; and 72.0% were white. The mean preoperative and postoperative estimates of difficulty were 44.3 ± 23.4 and 39.6 ± 24.7 mm, respectively. The mean absolute and actual differences between preoperative and postoperative estimates were 15.7 ± 13.6 and 4.8 ± 20.2 mm, respectively. We identified several demographic and anatomic variables statistically associated (P ≤ .05) with error in estimating difficulty.
Our models indicate that errors in the estimates of difficulty were related to demographic (age, gender, ethnicity, snoring) and anatomic (cheek flexibility, mouth opening) variables, with little or no dependence on radiographic variables or surgical experience.

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Clinical articleAccuracy of radiographs in classification of impacted third molar teeth

Abstract

Oral Surg

SUGI Supplemental Library User's Guide

Clinical article
Accuracy of radiographs in classification of impacted third molar teeth