Impact of CBCT on treatment decision related to surgical removal of impacted maxillary third molars: does CBCT change the surgical approach?

The relationship of the position of mandibular third molar impaction with the development of dental and periodontal lesions in adjacent second molars

OBJECTIVE

The aim of this study was to evaluate the effect of different positions of Mandibular third molar impaction teeth on dental and periodontal lesions of mandibular second molars and correlate the lesion severity with patient age.

MATERIALS AND METHODS

This retrospective study assessed 212 CBCT images of patients who visited the department of Oral and Maxillofacial radiology of XX university between 2017 and 2021. Periodontal and dental lesion effects of impacted third molars on mandibular second molars were evaluated. While dental lesions were classified as mild, moderate, and severe, periodontal lesions were classified as mild in cases not exceeding 2/3 of the root, and severe in cases exceeding 2/3 of the root. Pearson's chi-square tests, Mann-Whitney U or Kruskal-Wallis test were used for data analsis. A multivariate logistic regression model was constructed for further analysis.

RESULTS

Periodontal lesions were frequently observed in the second molar adjacent to the third molar (157 teeth, 74.1%), dental lesions were observed in 10%. Among the third molar positions, the mesioangular position was associated with a high (88%) prevalence of periodontal lesions (p<0.001), followed by the horizontal position (71%). The periodontal lesion was more severe in cases 30-39 years old and over 40 years old than in cases under 20 years old and 21-24 years old. Distoangular, horizontal and vertical/inverse positions are less likely to increase the severity of the periodontal lesion than the mesioangular position. (OR = 0.02; p <0.001, OR = 0.28; p =0.008, OR = 0.14; p <0.001,respectively).

CONCLUSIONS

The third molars are often impacted in the mesioangular position, and this position most increases the risk of periodontal infection in the second molars. Accurate diagnosis and evaluation can minimize complications, and CBCT is a reliable imaging technique in which the position of the third molars and their relationship with the 2nd molars can be evaluated.

Spatial Position and Anatomical Characteristics Associated with Impacted Third Molars Using a Map-Reading Strategy on Cone-Beam Computed Tomography Scans: A Retrospective Analysis

(1) Background: This study assessed the spatial position and anatomical features associated with impacted third molars through a map-reading strategy employing cone-beam computed tomography (CBCT). (2) Methods: The positioning of impacted third molars on CBCT was assessed using Winter's and Pell and Gregory's classifications. External root resorption in mandibular second molars was categorized according to Herman's classification. Additionally, the relationship between the mandibular third molar root apex and the mandibular canal was examined. Comparative statistical analysis was conducted using Fisher's exact test, with a significance level considered as 5%. (3) Results: The results indicated that, based on Winter's classification, 48.06 % of impacted teeth were positioned mesioangularly. Employing Pell and Gregory's classification, 43.22% of the impacted molars fell into positions B and C, with 54.2% classified as Class II. A notable 69.7% of teeth exhibited no contact between the root apex and the mandibular canal, and external root resorption in the distal aspect of the second molar was absent in 88.7% of cases. (4) Conclusions: Utilizing the map-reading strategy with CBCT scans to assess the anatomical positions and characteristics of impacted third molars enhances professional confidence and sets a standard for quality and safety in the surgical procedure for patients.

Indications and use of cone beam computed tomography in children and young individuals in a university-based dental hospital

BACKGROUND

The aim of this study was to evaluate the indications of cone beam computed tomography (CBCT) in children and young individuals in a university-based dental hospital and their association with age, gender and field of view.

METHODS

7131 CBCT scans, taken during 3-year period, were reviewed and a total of 649 pediatric patients (0-18 years) with complete request forms were included. Data related to gender, age, referring department, CBCT indications, field of view (FOV), region of interest (ROI), need for re-exposure and patients received more than one CBCT examination were recorded.

RESULTS

The mean age was 13.57 ± 3.52 years and "malocclusion and dentofacial anomaly" (28.7%) was the most common clinical indication. Facial trauma, dental trauma and supernumerary tooth in males; "malocclusion and dentofacial anomaly" and implant planning in females were recorded more frequently compared to other gender. Maxilla was the most frequently monitored ROI (35.1%) for patients. Small (≤ 10 cm) FOV was preferred in 58.1% of all patients. Large FOV was selected in the majority of patients who underwent CBCT scan for "malocclusion and dentofacial anomaly" (89.6%). The repeated scans constituted 2.3% of patients and 105 patients (16.2%) underwent multiple CBCT scans on different dates for mainly orthodontic follow-up.

CONCLUSIONS

The justification of CBCT scans was not fully compatible with current guidelines and mainly larger FOV was preferred. The number of CBCT examination in children and young individuals tends to increase.

TRIAL REGISTRATION NUMBER

Not applicable.

Long-term morphometric changes in the anterior alveolar bone in adolescents and adults after space closure: A retrospective study

OBJECTIVES

To analyse the morphometric changes in the anterior alveolar bone of both the maxilla and mandible after space closure and retention for 18-36 mo in adults and adolescents.

MATERIALS AND METHODS

Forty-two subjects with 4 first premolars extracted followed by retracting anterior teeth were included and divided into two age groups: adult group (4 males, 17 females, mean age: 23.67 ± 5.29 y, treatment duration: 27.95 mo, retention duration: 26.96 mo, ANB: 4.8 ± 2.1, U1-L1: 117.2 ± 9.2, U1-PP: 120.2 ± 7.2, L1-MP: 99.2 ± 5.3) and adolescent group (6 males, 15 females, mean age: 11.52 ± 1.21 y, treatment duration: 26.18 mo, retention duration: 25.79 mo, ANB: 5.2 ± 2.1, U1-L1: 116.0 ± 8.6, U1-PP: 119.8 ± 4.9, L1-MP: 99.7 ± 4.9). Alveolar bone height and thickness of anterior teeth in both groups were measured using cone beam computed tomography (CBCT) imaging performed at the pretreatment (T1), posttreatment (T2) and retention phases (T3). One-way repeated-measure ANOVAs were performed to evaluate the alveolar bone changes. Voxel-based superimpositions were performed to measure the amount of tooth movement.

RESULTS

After orthodontic treatment, the lingual bone height and thickness of both arches and the labial bone height of the mandible decreased significantly in both age groups (P < .05). Most of the labial bone height and thickness of the maxilla in both groups remained unchanged (P > .05). After retention, the lingual bone height and thickness increased significantly in both age groups (P < .05). The amounts of increased height ranged from 1.08 to 1.64 mm in adults and from 0.78 to 1.21 mm in adolescents, and the amounts of increased thickness ranged from 0.23 mm to 0.62 mm in adults and from 0.16 mm to 0.36 mm in adolescents. Obvious movements of the anterior teeth during retention were not found (P > .05).

CONCLUSIONS

Although lingual alveolar bone loss occurred in adolescents and adults during orthodontic treatment, continuous remodelling occurred in the later retention phase, which provides a reference for clinical treatment planning of bimaxillary dentoalveolar protrusion.

Does cone beam CT change the treatment decision for maxillary second and third molars? A prospective study

OBJECTIVES

To evaluate whether information from CBCT changes the treatment plan for maxillary second and third molars and to examine clinical and radiographic parameters with an impact on treatment decision.

METHODS

This prospective study included 260 maxillary third molars with superimposition onto the second molar in panoramic images (170 patients; mean age 28 years, range 16-63). An initial treatment plan was based on clinical findings and panoramic images. After CBCT, a final treatment plan was decided. Treatment was undertaken based on the final treatment plan. Through logistic regression analyses, impact of clinical and radiographic parameters on change in treatment plan, removal of the third molar vs no treatment, and removal of the second vs third molar were evaluated.

RESULTS

The treatment plan changed in 82 cases (32%). Sixteen cases (6%) changed from removal of the third molar to removal of the second molar. Regression analyses showed that severe resorption in the second molar was significantly related to a change in treatment plan. Removal of a third molar was decided in 180 cases and regression analyses identified that mesioangulation of the third molar, marginal bone loss, superficial resorption, and age were significantly related to removal of the third molar vs no treatment. Thirty second molars were removed, and regression analyses showed that severe resorption was significantly related to removal of the second molar instead of the third molar.

CONCLUSIONS

Parameters such as resorption evaluated in CBCT can modify the treatment decision, resulting in removal of the second and/or the third molar.

Palatal approach for surgical removal of mesioangularly impacted maxillary third molar - a pilot study

OBJECTIVE

This study aimed to investigate the application of the palatal approach for surgical removal of IMTM, and to evaluate its success rate, surgical duration, postoperative outcomes, and incidence of complications.

METHOD

Patients with mesioangularly IMTM (Archer Classification Class B) in the none-buccal position to the adjacent second molar, which were indicated for surgical removal, were enrolled in this study. The patients were assigned into two groups according to the surgical approach: the buccal or palatal approach. The impacted tooth positions, diagnosis, past dental and medical history, and radiographic examination were recorded pre-operatively. The duration, surgery details, and surgical complications were documented during the surgery.

RESULT

40 teeth were enrolled in our study. All teeth were removed completely. The operation time was significantly shorter in the palatal approach group compared to the buccal approach group (13.3 ± 2.8 min vs. 22.3 ± 5.5 min, P<0.001). The incidence of traumatic ulcers of the lips was significantly higher in the buccal approach group than in the palatal approach group (7/20 vs. 0/20, P = 0.008).

CONCLUSION

It is more efficient to perform surgery with a palatal approach if a Class B mesioangularly IMTM is located in the non-buccal aspect of the adjacent second molar.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR2000040063.

Radiologic Evaluation of the Fossa Navicularis on Dry Skull: A Comparative CBCT Study

Fossa navicularis (FN) is defined as bony depression that is not always present and is located anterior to the foramen magnum and pharyngeal tubercle on the inferior aspect of the basilar part of the occipital bone. It has been reported that FN can create an infection spread path from the pharynx to the intracranial structures. Therefore, the diagnosis of this variation is important. Although cone beam computed tomography (CBCT) diagnostic accuracy has mostly been verified in detection and quantification particularly on human skulls, there is no study comparing morphometric measurements between direct measurement on the skull and CBCT measurement. The main object of this study is to evaluate the presence of FN on dry bones and CBCT images of the same dry skull and to examine the morphometric and morphological features of this formation. Thirty-two random craniums that were made available for this study that did not have any fractures or deformities of the cranial base were examined. The sagittal diameter, transverse diameter, and depth of the FN was measured both directly on dry skulls and radiologically on CBCT images of dry skull. In addition, the shape of FN (SFN) was determined. FN was detected in 10 (31.25%) of 32 craniums examined with both modalities. It was determined that sagittal diameter of the FN, transverse diameter of the FN, depth of the FN, and the shape of FN did not show a statistically significant difference between the 2 measurements. Unlike the literature, FN was investigated on dry bones both directly and in CBCT images in this study. In contrast to previously thought the FN may be smaller according to this findings, and this small variation can be detected with CBCT images. According to this findings, it can be said that morphometric evaluations on CBCT are accurate and reliable, and CBCT is a safe method for clinical diagnosis and treatment.

Orthodontic treatment of substituting third molars for missing permanent molars

INTRODUCTION

This study aimed to evaluate the orthodontic effect and efficiency of substituting third molars for missing first or second permanent molars systematically.

METHODS

Forty-six patients (69 third molars total) with missing permanent molars replaced by third molars were selected. The angulation, crown-to-root ratio, and periodontal condition of the third molars before and after treatment were compared. The American Board of Orthodontics Objective Grading System was used to evaluate the alignment and occlusion of third molars after treatment. The duration of orthodontic treatment and third molar replacement therapy were also recorded.

RESULTS

The average orthodontic treatment time was 33.9 ± 5.6 months, and the average angulation change of third molars during treatment was 49.8 ± 29.8°. The average height of mesial alveolar bone increased by 4.8 ± 0.5 mm in patients whose third molars were mesially inclined or horizontally impacted. The root length of adult patients decreased by 0.72 ± 0.02 mm on average, and the average gingival recession was 0.10 mm, both of which were not statistically significant. The average score for each third molar evaluated by the American Board of Orthodontics Objective Grading System was 1.8 ± 0.5 points.

CONCLUSIONS

If the indications and timing of treatment were well-controlled, third molars would be excellent substitutes for missing first or second permanent molars through the orthodontic method.

Orthodontic traction of an impacted maxillary third molar through a miniscrew-anchored cantilever spring to substitute the adjacent second molar with severe root resorption

BACKGROUND

An orthodontic traction technique with a miniscrew-anchored cantilever spring was used for the traction of a deeply impacted maxillary third molar to substitute its adjacent second molar with severe root resorption.

CASE DESCRIPTION

A 30-year-old woman sought multidisciplinary treatment planning for a second molar with severe root resorption caused by a deeply impacted third molar. Panoramic radiographs and cone-beam computed tomographic images showed that the third molar was located on the apical and palatal side of the second molar and that the second molar had severe root resorption. The second molar was removed, and the impacted third molar was orthodontically tractioned occlusally with the aid of a miniscrew-anchored cantilever spring. After 12 months of orthodontic treatment, the maxillary left third molar was successfully tractioned occlusally and well aligned with adjacent teeth for the substitution of the second molar. The patient was satisfied with the treatment outcome.

PRACTICAL IMPLICATIONS

A palatal miniscrew-anchored cantilever spring is an effective and viable technique for the orthodontic traction of deeply impacted third molars to substitute second molars with severe root resorption.

Can CBCT change the level of confidence of oral maxillofacial surgeons in mandibular third molar management?

This study analyzed the impact of CBCT on the level of confidence in diagnostic and treatment thinking in mandibular lower molar (M3M) clinical management. Thirty cases for which panoramic radiographs and CBTC images were available were selected and classified according to radiologic signs indicating the proximity of the M3M to the mandibular canal (interruption of the radiopaque borders of the canal of the mandibular canal wall, darkening of the roots, and diversion or narrowing of the canal, n = 10 for each classification). Twelve oral and maxillofacial surgeons (OMS) contributed to this study by answering two questionnaires. The first questionnaire contained a clinical description of the case and a panoramic radiograph. After 30 days, a second questionnaire with the same clinical illustrations and tomographic multiplanar reconstruction images was administered. Both questionnaires asked specialists to rate diagnostic confidence, the surgical complexity, chosen treatment, and surgical confidence. In approximately 40% of answers, CBCT images had a positive impact on ratings of diagnostic confidence and treatment thinking confidence, and in 24.4%, they increased the surgical complexity score. There was no change in the treatment plan following the use of CBCT, but the CBCT examination was a determining factor for diagnosis and treatment planning in 72.8% of the answers CBCT improved the confidence level in diagnostic and treatment thinking of the M3M management while also increasing the perceived level of surgical complexity. The findings of this study support the need to consider using CBCT in diagnosis and treatment planning for M3Ms with radiographic signs such as darkening of the roots, interruption of the radiopaque borders of the mandibular canal, or deviation of the mandibular canal and narrowing of the roots.

Comparison of CBCT and panoramic radiography for the assessment of bone loss and root resorption on the second molar associated with third molar impaction: a systematic review

OBJECTIVE

To investigate whether the use of cone beam CT (CBCT) changes the diagnosis of external root resorption (ERR) or marginal bone loss (MBL) involving a second molar adjacent to an impacted third molar.

METHODS

A systematic search was applied in PubMed, EMBASE, Scopus, Web of Science, LILACS, Google Scholar, OpenGrey, and ProQuest. Studies assessing the detection of ERR or MBL in a second molar adjacent to an impacted third molar through CBCT and panoramic radiography (PAN) were included. Prevalence and agreement between PAN and CBCT on the detection of ERR and MBL were collected. The risk of bias was assessed using the MAStARI.

RESULTS

A total of 593 papers were identified, and after a 2-phase selection, 5 studies were included in the narrative synthesis. Regarding ERR, its prevalence in PAN was reported from 5.31 to 19.5% and from 22.8 to 62.0% in CBCT. The percentage of agreement varied from 28.5 to 74.0%. The prevalence of MBL varied from 21.9 to 62.9% in PAN, while those values varied from 21.6 to 80% in CBCT images. The percentage of agreement between PAN and CBCT for the detection of MBL ranged from 66.0 to 85.0%. Four studies presented low risk of bias and one had moderate risk.

CONCLUSIONS

More ERR and MBL are assessed in CBCT compared to PAN. There is a considerable agreement between PAN and CBCT assessment of ERR and MBL, however, mostly related to the absence of the pathology rather its presence.

Delaying Intraoral Radiographs during the COVID-19 Pandemic: A Conundrum

Background

The COVID-19 pandemic has made dentists very assiduous about cross-infection during dental treatment, thereby delaying dental radiographs for treatment. However, patients needing dental emergency treatment in the ongoing pandemic require relevant intra/extraoral dental radiography for adequate diagnosis and treatment planning.

Methods

This article is aimed at adding to the hot debate: Is delay for intraoral radiographs justified or a possible proxy? As a narrative review, it provides an insight into the reasons for delaying intra-oral dental radiographs during in the pandemic and options of the nontraditional radiographic techniques available until the pandemic subsides. Discussion and Conclusion. Cross-contamination concerns through respiratory droplets grow while using intraoral film holders that stimulate gag reflex, coughing, saliva secretion, and if proper disinfection protocols are not applied. Since the patients' acquiring emergency dental treatment cannot be neglected, the return-to-work guidelines by the health regulatory bodies urge to prioritize extraoral radiographic imaging techniques to curb the infection, offering the best diagnostic efficacy. The dental professionals can consider cone-beam computed tomography (CBCT) scans and sectional dental panoramic radiographs (SDPRs), followed by a risk assessment for COVID-19, a safer modality in reducing cross-contamination and assuring an innocuous environment for both patient and coworkers.

Risk factors for external root resorption of maxillary second molars associated with third molars

Purpose

This study aimed to evaluate the diagnostic performance of panoramic images compared to cone-beam computed tomography (CBCT) imaging for maxillary third molar (M3)-associated external root resorption (ERR), and to identify the risk factors of ERR on panoramic images.

Materials and Methods

The study population was composed of all patients who underwent panoramic imaging at Dankook University Dental Hospital from May to October 2019. In total, 397 cases of maxillary M3s in 247 patients (147 men and 100 women) were included. The diagnostic accuracy of ERR in panoramic images compared to CBCT images was evaluated using the chi-square test. To identify risk factors for ERR, dental records and panoramic findings were evaluated by logistic regression analysis.

Results

The diagnostic accuracy of ERR on panoramic images was 0.79 compared to CBCT images (P<0.05). Superimposition of M3s onto second molars (M2) was associated with an approximately 33 times higher risk of ERR than separated M3s (P<0.05). Impacted M3s showed a 5 times higher risk of ERR than erupted M3s (P<0.05).

Conclusion

ERR related to M3s is a common clinical condition, and superimposition of M3 onto M2 on panoramic images was the most important risk factor for ERR. It seemed that CBCT examinations for maxillary M3s might be indicated for ERR diagnosis especially if panoramic radiographs show superimposition of M3 onto M2. Impaction itself was also a risk factor, and it should be carefully examined.

Maxillary Third Molar Tooth Accidentally Displaced in Buccal Space: Report of Two Cases

The extraction of retained and completely impacted third molars is one of the most common surgical procedures performed by dental practitioners with low rates of complications. The accidental displacement during the surgeries of the maxillary third molar into adjacent anatomical spaces is one of the most critical problems that can arise. The most common sites of migration during surgical interventions are the infratemporal fossa, the pterygomandibular space, the maxillary sinus, the buccal space, and the lateral pharyngeal space. In this paper, two cases in which a maxillary third molar accidentally was displaced into the buccal space are presented, the retrieval of the tooth via intra-oral approach is explained, and the anatomical spaces implications are discussed.

Dental follicles promote soft tissue management in surgical exposure of labially impacted maxillary canine

Background

The present study aimed to report a technically improved operation on the surgical exposure of labially impacted maxillary canine, elaborating the management of soft tissue to achieve better aesthetic results, and post-treatment periodontal health.

Methods

Patients sought orthodontic treatment with unilateral labially impacted maxillary canines were selected in this study. The impacted teeth were assigned to the experimental group and contralateral unimpacted canines were assigned to the control group. The impacted canines were surgically exposed with dissected dental follicle (DF) stitching to muscle and mucosa surrounding the crowns. The gingival index (GI), probing depth (PD), the width of the keratinized gingiva (WKG), gingival scars (GS), bone loss (BL), and apical root resorption (ARR) were recorded after the removal of the fixed appliance. A two-sample t-test was used for independent samples for parametric variables.

Results

A total of 24 patients with unilateral maxillary canine impaction were successfully treated. The outcomes of GI, WKG, GS, BL, and ARR did not indicate statistical significance between the experimental group and the control group.

Conclusions

The preservation of DF promotes soft tissue management in combined surgical and orthodontic treatment of labially impacted maxillary canine to achieve better periodontal status.

Trial Registration Chinese Clinical Trial Registry ChiCTR2000029091, 2020-01-12.

Evaluation and Management of Impacted Teeth in the Adolescent Patient

The most common oral and maxillofacial surgical procedure in adolescents is excision of impacted third molars. Adolescent patients should be evaluated for third molars starting around age 16 years unless symptomatic at an earlier age. The dental examination should include panorex imaging to assess development, pathologic condition, and possibility of eruption versus impaction. Various classification systems are available to identify the position and difficulty of the proposed surgical procedure. Retained impacted teeth increase the patient's risk of various morbidities including recurrent infection, damage to adjacent teeth, cysts and other lesions, and unexplained pain.

Evaluation the relationship between the position and impaction level of the impacted maxillary third molar teeth and marginal bone loss, caries and resorption findings of the second molar teeth with CBCT scans

OBJECTIVE

To evaluate the relationship between the position and impaction level of the impacted maxillary third molar teeth and marginal bone loss, caries and resorption findings on the distal surface of the second molar teeth with cone beam computerized tomography (CBCT) scans.

METHODS

All CBCT images of 189 impacted maxillary teeth belonging to 121 patients were examined by an observer. After determining the position and impaction level of the impacted maxillary third molar teeth, presence of caries, resorption and marginal bone loss in the distal of the second molar tooth were evaluated. IBM SPSS Statistics 22.0 (IBM Corp. Released 2013. IBM SPSS Statistics for Windows, Version 22.0. Armonk, NY: IBM Corp.) was used for statistical analyses and calculations. Data were analysed using the Chi-square test and Fisher's exact test.

RESULTS

A statistically significant difference was found in terms of the impaction level of the impacted maxillary third molar tooth and the presence of caries in the distal surface of the second molar tooth, in terms of the impaction level of the impacted third molar tooth and the presence of marginal bone loss in the distal surface of the second molar tooth. A similar difference was found in terms of the impaction level of the impacted third molar tooth and the presence of root resorption in the distal surface of the second molar tooth.

CONCLUSION

These data on the natural history of impacted maxillary third molars may contribute to both more accurate estimates of the risk of complications associated with these teeth and determination of the prophylactic approach to asymptomatic impacted third molars.

Guidelines for oral and maxillofacial imaging: COVID-19 considerations

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing the current coronavirus disease 2019 (COVID-19) pandemic, is not only highly infectious but can induce serious outcomes in vulnerable individuals including dental patients and dental health care personnel (DHCPs). Responses to COVID-19 have been published by the Centers for Disease Control and Prevention and the American Dental Association, but a more specific response is required for the safe practice of oral and maxillofacial radiology. We aim to review the current knowledge of how the disease threatens patients and DHCPs and how to determine which patients are likely to be SARS-CoV-2 infected; consider how the use of personal protective equipment and infection control measures based on current best practices and science can reduce the risk of disease transmission during radiologic procedures; and examine how intraoral radiography, with its potentially greater risk of spreading the disease, might be replaced by extraoral radiographic techniques for certain diagnostic tasks. This is complemented by a flowchart that can be displayed in all dental offices.

Can diagnostic changes caused by cone beam computed tomography alter the clinical decision in impacted lower third molar treatment plan?

OBJECTIVES

This study observed whether changes in diagnosis caused by analysis of three-dimensional images can lead to alterations in the treatment plans of impacted lower third molars (ILTMs).

METHODS

Sets of panoramic (PAN) - cone beam computed tomography (CBCT) of 218 patients were assessed for ILTM classification, contact with mandibular canal, contact and resorption of the lower second molar (LSM), intraoperative planning and post-operative expectations.

RESULTS

Percentage agreement and McNemar test compared PAN vs CBCT assessments. Logistic regression analyzed the dependency of change in surgical planning considering the changes in diagnostic features; descriptive statistics was used to observe the expectation of post-operative complications and paresthesia. Differences were found between PAN vs CBCT for classification of impaction and positioning, LSM relationship, choice for crown and root sectioning and expectation of post-operative complications (all with p < 0.001). Logistic regression indicated that the change in diagnosis caused by CBCT examination did not change the clinical decision to extract ILTM but altered the planning of intraoperative steps such as osteotomy, crown sectioning and relaxing incision. The expectation of post-operative complications decreased when professionals planned the ILTM removal using tri-dimensional images.

CONCLUSIONS

We concluded that changes in the diagnosis after CBCT examination can lead to alterations in the treatment plan of impacted lower third molar.

Teeth Impaction and Structural Teeth Anomalies

Dentists and oral and maxillofacial radiologists have used periapical, occlusal, panoramic, and cephalometric radiographs for many years for diagnosing dental anomalies, especially before orthodontic or surgical treatment. Cone beam computed tomography was developed in recent years especially for the dental and maxillofacial region. Thus it has become the imaging modality of choice for many clinical situations, such as the assessment of dental impaction and structural teeth anomalies or other associated diseases and disorders (e.g., Gardner's syndrome, cleidocranial dysplasia). This article reviews different aspects of dental impaction and its possible effects on adjacent structures such as external root resorption, marginal bone loss, as well as describing structural dental anomalies. It provides a systematic analysis of their characteristic features and imaging findings for general radiologists to achieve a precise diagnosis and an optimal interpretation.

Marginal bone loss in the second molar related to impacted mandibular third molars: comparison between panoramic images and cone beam computed tomography

BACKGROUND

Deciding whether or not to extract third molars remains a controversial situation in dental practice. Image exams support this decision by enabling a close view of the third molar, its adjacent bone and its relationship with the second molar. This study aimed to assess and compare second molar bone loss adjacent to impacted mandibular third molar in panoramic radiographs (PAN) and cone beam computed tomography (CBCT) scans.

MATERIAL AND METHODS

A sample of 70 patients was selected (n=124 teeth). Each patient had a set of a panoramic radiograph and CBCT scans consecutively taken for dental treatment purposes. In PAN and CBCT, mandibular third molars were classified based on their position and bone loss of the adjacent second molar. Agreement between PAN and CBCT scans was assessed and quantified.

RESULTS

Outcomes of bone loss assessment were different between PAN and CBCT scans (p<0.05). Bone loss was found in 62.9% of the PAN, while in CBCT scans it was found in 80%. In particular, nearly 29% (n=27) of the teeth that were classified without bone loss in PAN were classified with bone loss in CBCT scans. Mesioangular and horizontal third molars had a statistically significant association with bone loss of the adjacent second molars (p<0.05). In general, PAN underestimated the severity of bone loss compared to CBCT scans (p<0.05).

CONCLUSIONS

Diagnosing second molar bone loss due to impaction of adjacent third molar in PAN may be challenging because of false negatives. Impacted third molars justify preoperative CBCT scans if second molar bone loss needs to be precisely assessed for a more detailed and reliable treatment plan.