Investigating the anatomical relationship between the maxillary molars and the sinus floor in a Chinese population using cone-beam computed tomography

Evaluation of maxillary sinus changes following molar distalization using clear aligners: A three-dimensional study

OBJECTIVE

To evaluate the impact of molar distalization with clear aligners (CAs) on maxillary sinus parameters and its proximity to the root apices of maxillary molars using Cone Beam Computed Tomography (CBCT).

METHODS

The study involved pre- and post-treatment CBCT images of 27 adult patients. MIMICS 21.0 software was used to measure maxillary sinus volume and surface area, while Invivo Dental 6.0 program was used to measure the sinus diameters and proximity of the maxillary molar root apices to the sinus floor.

RESULTS

Post-treatment, there was a marked increase in the average volume and surface area of the maxillary sinus on both sides; however, changes in dimensions were not statistically significant. Sinus proximity to the root apices of the maxillary molars showed statistically significant differences, particularly on the left side for all roots. Gender and age impacted the outcomes, with males and younger individuals showing more pronounced changes. No significant differences were observed between the left and right sinuses in all parameters.

CONCLUSION

Molar distalization with CAs increases maxillary sinus parameters, more notably in younger and male patients. All molar teeth roots moved toward the sinus, particularly the mesiobuccal root of the maxillary second molar protruded to the sinus.

AI model to detect contact relationship between maxillary sinus and posterior teeth

Objectives

To establish a novel deep learning networks (MSF-MPTnet) based on panoramic radiographs (PRs) for automatic assessment of relationship between maxillary sinus floor (MSF) and maxillary posterior teeth (MPT), and to compare accuracy of MSF-MPTnet, dentists and radiologists identifying contact relationship.

Study design

A total of 1035 PRs and 1035 Cone-beam computed tomographys （CBCT）images were collected from January 2018 to April 2022. The relationships were classified into class I and II by CBCT. Class I represents non-contact group, and class II represents contact group. 350 PRs were randomly selected as test dataset and accuracy of MSF-MPTnet, dentists, and radiologists was compared.

Results

The intraclass correlation coefficient of dentists was 0.460-0.690 and it was 0.453-0.664 for radiologists. Sensitivity and accuracy of MSF-MPTnet were 0.682-0.852and 0.890-0.951, indicating that the output performance of MSF-MPTnet was reliable. Accuracy of maxillary premolars and molars were 79.7%-90.3 %, 76.2%-89.2 % and 72.9%-88.3 % in MSF-MPTnet model, dentists and radiologists. Accuracy of class I relationship in the MSF-MPTnet model (67.7%-94.6 %) was higher than that of dentists (56.5%-84.6 %) in maxillary first premolars and right second premolar, and accuracy of class I relationship in the MSF-MPTnet model is also higher than radiologists (40.0%-78.1 %) in all teeth positions (p < 0.05).

Conclusions

MSF-MPTnet model could increase detecting accuracy of the relationship between MSF and MPT, minimize pseudo contact relationship and reduce frequency of CBCT use.

Anatomic relationship between the root apex of maxillary molars and maxillary sinus in the presence of antagonist teeth: A Kwak's method with divisions

OBJECTIVE

The purpose of the study was to evaluate the proximity between the root apices of maxillary molars and maxillary sinus floor using cone-beam computed tomography (CBCT) in the southern Turkish subpopulation.

DESIGN

For the study, 246 CBCT images were analyzed. The absence of antagonist teeth was excluded. Kwak's types III and V were detailed with three divisions. Division M; the penetration of the mesial root only, Division D; the penetration of the distal root only, and Division MD; the penetration of both buccal roots. The distance between the maxillary sinus and the root apices was measured. Student's t-test, one-way ANOVA, and chi-square were used for statistical analysis.

RESULTS

The penetration of maxillary molars was 24.40%. The highest prevalence belonging to Type I. Division MD was 44.35% for Type III and 40.42% for Type V. Division M was higher than Division D. The distances between the sinus and root apices were 1.35-2.41 mm in Type I. The distance decreased with age (p < 0.05).

CONCLUSION

Both buccal root penetration into the sinus was higher than the single root penetration. The distance of the second molar root apices to the sinus was closer than the first molar. One-quarter of the first and second molars were inside the sinus. A greater likelihood of penetration of the root apices into the sinus with increased age.

Evaluation of Dimensional Changes in Maxillary and Frontal Sinus in Adult Patients With Anterior Open Bite and Normal Overbite: A Retrospective Cone Beam Computed Tomography (CBCT) Study

INTRODUCTION

An anterior open bite is a form of vertical discrepancy that presents as a lack of contact between maxillary and mandibular segments. The treatment modalities usually involve either intrusion of posterior teeth or extrusion of anterior or a combination of both. The anatomical relationship between the apex of the maxillary molar roots to the inferior wall of the maxillary sinus floor is crucial in planning posterior intrusion. The paranasal sinuses influence the growth of the facial structures that eventually get altered in various malocclusions. Studies have proven that the height of the sinus gets modified in anterior open bite owing to pneumatization. This study aims to evaluate the distance from the root apex of maxillary first molars (mesiobuccal, distobuccal, and palatal roots) to the maxillary sinus floor to evaluate the significance of the vertical pneumatization of the sinus on planning for true intrusion in anterior open bite and to assess the correlation between frontal and maxillary sinuses in an anterior open bite.

METHODS

This retrospective study evaluated 30 pre-treatment cone beam computed tomographies (CBCTs) of patients out of which 15 were with anterior open bite and 15 with ideal overbite. Linear measurements were carried out using care stream software in CBCTs.

RESULTS

There was a significant correlation between the distance of the palatal root and the distobuccal root of the maxillary first molar to the maxillary sinus floor bilaterally in the anterior open bite (p<0.04). A significant moderate positive correlation of the maxillary and frontal sinus height in anterior open bite (p<0.006). A significant moderate negative correlation between the distance from the palatal root to the maxillary sinus floor and maxillary sinus height in anterior open bite (p<0.001).

CONCLUSION

Vertical pneumatisation of the maxillary sinus has caused a significant negative correlation between the apex of the palatal root of the maxillary first molar tooth and the maxillary sinus floor in the anterior open bite. The palatal root being the closest to the sinus floor, and the distobuccal root being second nearest. There is a significant correlation between the height of the sinuses in the anterior open bite.

Characteristics of CBCT versus panoramic signs of the surrounding bone of molar root protrusions into the maxillary sinus

The study aimed to (a) investigate the amount and characteristics of the surrounding bone of protruded molar roots into the maxillary sinus using cone-beam computed tomography (CBCT) and (b) assess the correlation between the amount of bone with panoramic high-risk signs. Radiographs of 408 roots protruding beyond the sinus floor were evaluated. Axial CBCT images were used to investigate then classify eight characteristics of surrounding bone: no bone; bone < half the root girth in the proximal or buccal-palatal aspect; bone covering half the root girth in the proximal or buccal-palatal aspect; bone > half the root girth in the proximal or buccal-palatal aspect; and, complete bone. These were then grouped into four degrees of bone support: no bone; bone ≤ half the root girth; bone > half the root girth; and, complete bone. Panoramic signs were subclassified as: projection of root; interruption of the sinus floor; darkening of the root; upward curving of the sinus floor; absence of periodontal ligament space; and, absence of the lamina dura. Correlation between the degree of bone and the panoramic signs was evaluated using the Chi-square or Fisher's exact tests. Positive and negative predictive values, sensitivity, specificity, accuracy, and receiver operating characteristic analysis were calculated. Complete bone support was the most common. 'Projection of root' had a high negative predictive value and sensitivity. 'Absence of the periodontal ligament space and lamina dura' had a high positive predictive value, specificity, accuracy, and area under the curve. These two signs were significantly correlated with the degree of bone support.

Cone-Beam Computed Tomography (CBCT)-Based Assessment of the Alveolar Bone Anatomy of the Maxillary and Mandibular Molars: Implication for Immediate Implant Placement

Purpose This study aims to examine specific aspects of socket morphology, including buccal and palatal/lingual bone width, interradicular bone (IRB) width, and assessments of root apices and furcation proximity to the vital structures of the maxillary and mandibular first and second molars using cone-beam computed tomography (CBCT). Materials and methods The study involved the analysis of 400 maxillary and mandibular first and second molars. Various measurements were taken to assess socket morphology, including mesiodistal (MD) and buccolingual (BL) width, buccal and lingual bone thickness at 2 mm apical to the alveolar crest, IRB width at 2 mm from the furcation, and the distance between the root apices and furcation to vital structures, such as the floor of the maxillary sinus (FMS) and inferior alveolar nerve (IAN). Results The mesiobuccal (MB) root of the second molar commonly intruded into the sinus, followed by the palatal root of the maxillary first molar. The mean FMS-F distance was 7.17 + 3.98 mm, and it was 7.2 + 2.72 mm for maxillary first and second molars, respectively. The mean IRB width was 2.77 + 0.96 and 2.29 + 0.74 mm for the first and second molars. The mandibular second molar had the shortest distance to the IAN in comparison to the first molar. For maxillary teeth, 7% of the first and 4% of the second molars presented alveolar anatomy adequate for immediate implant placement, compared to 84% and 50% of mandibular first and second molars. Conclusion Understanding the local alveolar bone anatomy of molars and its relationship to vital structures is crucial for the effective planning of implant treatments.

[Relationships between the inferior wall of maxillary sinus and the roots of the maxillary molars]

OBJECTIVE

The aim of the study is to evaluate the position of the roots of the first and second upper molars relative to the bottom of the maxillary sinus (maxillary sinus) according to cone-beam computed tomography (CBCT).

MATERIAL AND METODS

The CBCT scans of 150 patients (69 men and 81 women) from the database of the X-ray department of the 11th City Clinical Hospital of Minsk who applied for dental care were studied. There are 4 variants of vertical relationships between the roots of the teeth and the lower wall of the maxillary sinus. At the contact of the molar roots and the bottom of the HPV, 3 variants of the horizontal relationship between the roots of the teeth and the bottom of the maxillary sinus in the frontal plane were identified.

RESULTS

The root apices of the maxillary molars can be located below the level of the MSF (type 0; 16.69%), contact with MSF (types 1-2; 72%) or protrude into the sinus cavity (type 3; 11.31%) at a distance of up to 6.49 mm. The roots of the second maxillary molar showed greater proximity to the MSF than the first molar roots and more often protruded into the maxillary sinus. The most common type of horizontal relationship between the molar roots and the MSF, in which the lowest point of the MSF was located centrally between buccal and palatal roots. It was found that the proximity between the roots and the MSF correlates with maxillary sinus vertical dimension. This parameter was significantly greater in type 3 when the roots protruded into the maxillary sinus than in type 0, when there was no contact between the MSF and the root apices of the molar teeth.

CONCLUSION

Significant individual variability in the anatomical relationships between the roots of the maxillary molars and the MSF indicates the need for the mandatory appointment of cone-beam computed tomography in preoperative planning for the extraction of these teeth and/or their endodontic treatment.

Anatomical Evaluation of Posterior Maxillary Roots in Relation to the Maxillary Sinus Floor in a Saudi Sub-Population: A Cross-Sectional Cone-Beam Computed Tomography Study

To evaluate the mean distance and differences between posterior maxillary teeth and maxillary sinus floor (MSF) concerning the age and gender of the patients, a total of 124 maxillary sinuses and 496 posterior maxillary teeth were randomly selected in 62 cone-beam computed tomography (CBCT) images. Mean distances between posterior maxillary roots (PMRs) from different teeth and the MSF were measured using a calibrated tool in the software. Other relations regarding the gender and age of the patients were determined. The mean root-MSF distances in the right and left first premolars were more significant compared to the second premolars. No significant relation was found between the apices of the right and left first and second molar roots and the floor of the maxillary sinus concerning gender. A statistically significant relation was found between the apices of the buccal root of the right first premolar, right and left first and second molars and floor of the maxillary sinus concerning the age group 21-40 years (p-value = 0.009). This study showed that the second molar mesiobuccal root apex is frequently related to the sinus floor. Differences were reported concerning age, concerning the distance between posterior maxillary teeth and the maxillary sinus floor. CBCT technology helped provide the clinical proximity between the MSF and the posterior teeth root apices during the treatment planning.

Treatment effects after maxillary total arch distalization using a modified C-palatal plate in patients with Class II malocclusion with sinus pneumatization

INTRODUCTION

The purpose of this study was to evaluate the treatment effects after molar distalization using modified C-palatal plates in patients with Class II malocclusion with maxillary sinus pneumatization.

METHODS

This study consisted of 70 lateral cephalograms derived from cone-beam computerized tomography images of 35 patients with Class II malocclusion (mean age 22.3 ± 7.4 years) who had undergone bilateral total arch distalization of the maxillary dentition using modified C-palatal plates. The samples were divided into 2 groups according to sinus pneumatization; group 1 (n = 40), cephalograms with sinus pneumatization and group 2 (n = 30) cephalograms without sinus pneumatization. Paired t tests and independent-sample t tests were used to compare the changes in each group and between groups.

RESULTS

The distal movement of the maxillary first molars was 4.3 mm for group 1 and 3.5 mm for group 2, with the intrusion of 1.4 mm and 2.5 mm, respectively. There was no statistically significant difference between the 2 groups. Group 1 showed 3.5° of distal tipping of the maxillary second molars, which was significantly greater than the 0.2° in group 2 (P <0.05). The total treatment period, including distalization, was 2.2 years for group 1 and 1.9 years for group 2, but the difference was not significant.

CONCLUSIONS

There was no significant difference in the amount of distal movement and intrusion of the maxillary first molars between groups 1 and 2. Therefore, these results suggest that regardless of sinus pneumatization, molar distalization using temporary skeletal anchorage devices in Class II patients can be performed as a nonextraction treatment.

Effect of the Maxillary Sinus on Tooth Movement during Orthodontics Based on Biomechanical Responses of Periodontal Ligaments

The maxillary sinus is a common anatomic limitation for orthodontic tooth movement. The effect of orthodontic forces on a particular anatomy can be studied using finite element analysis (FEA). Our study aimed to determine the effect of different tooth penetration depths into the maxillary sinus floor (MSF) on the orthodontic force system for bodily tooth movement. Using the cone-beam computed tomography of a patient with low MSF, we modeled the geometry of canine, premolar, and molar teeth with their periodontal ligaments and the alveolar bone surrounding them. The models were manually modified to simulate different root penetration depths. Thereafter, the center of resistance and stress distributions for teeth penetrating into the MS were determined using FEA. Moreover, the force systems for teeth with a low MSF to varying degree were evaluated based on the FEA results. During orthodontic tooth movement, the individual differences in the periodontal anatomy should be considered. The CR position decreases with the penetration depth, while the average hydrostatic stress in the PDL increases rapidly. In this paper, we present the correction coefficients of the orthodontic force and moment for a tooth penetrating into the MSF, which is necessary for personalized treatment planning.

Three-dimensional assessment of the favorability of maxillary posterior teeth intrusion in different skeletal classes limited by the vertical relationship with the maxillary sinus floor

Background

Understanding the anatomical relationship between the maxillary sinus floor (MSF) and the posterior maxillary teeth (PMT) is important when planning the orthodontic intrusion of the posterior teeth. This study aimed to determine the vertical relationship between posterior maxillary teeth and maxillary sinus floor in different skeletal classes in the Chinese adult population.

Methods

This is a retrospective cross-sectional study involved cone beam computed tomography images of 298 adult patients (145 males and 153 females) between 20 and 45 years old. The sample was categorized according to A point, Nasion, B point (ANB) angle into 102 Class I, 102 Class II, and 94 Class III malocclusion. Non-parametric Wilcoxon Mann–Whitney U and Kruskal–Wallis tests were used to compare the studied groups. The Intra-class Correlation Coefficient (ICC) was used to assess the intra- and inter-observer reliability analysis.

Results

Overall, there was a statistically significant difference in the mean distance between both genders (P < 0.001). The measured distance increased with age in all posterior tooth roots (P < 0.001). The root apex in the sagittal view appeared to be closer to the maxillary sinus than in the coronal view; 2.2 ± 4.3 and 3.1 ± 5.5 mm, respectively. The most frequent root scores were Type 1 and Type 2P. In both sagittal and coronal views, Class I demonstrated a higher Type 2P prevalence, whereas Class III showed a lower prevalence. The second molars’ mesiobuccal root had the largest number of penetration in the three examined skeletal classes.

Conclusions

Maxillary molars of Class I malocclusion with the majority of Type 2P root-sinus relationship have the highest possible risk of root resorption during molar intrusion due to cortical bone encroachment, while Class III malocclusion showed the least possible risk.

Supplementary information

The online version contains supplementary material available at 10.1186/s13005-022-00316-3.

Location of the Maxillary Posterior Tooth Apices to the Sinus Floor in an Egyptian Subpopulation Using Cone-beam Computed Tomography

Introduction

The aim of this study was to evaluate the location of the apices of the maxillary posterior teeth to the maxillary sinus floor (MSF), the symmetry between both sides and the possible variations between males and females using cone-beam computed tomography (CBCT) in an Egyptian subpopulation.

Materials and Methods

CBCT images were collected from 120 patients (240 second premolars, 480 1^st and 2^nd molars, 1680 roots). The proximity of roots of maxillary second premolar and 1^st and 2^nd molars to the floor of the sinus was categorized into three categories: inside the sinus floor (IS), touching the sinus floor (TS) or outside the sinus floor (OS). The correlation of the distance with gender was analyzed as well as for symmetry. Friedman's test was used to compare between different roots and the Dunn's test was used for pair-wise comparisons when Friedman's test was significant. The Mann-Whitney U test was used to compare males and females. The significance level was set at P≤0.05.

Results

The highest prevalence of roots outside the sinus was found with second premolar (right and left) followed by palatal roots of right and left second molar. In addition, the highest prevalence of roots inside the sinus was found with mesiobuccal roots of maxillary second molar followed by the palatal root of maxillary first molar. There was no statistically significant difference between males and females or between both sides.

Conclusion

Neither gender nor side variations regarding the proximity to the maxillary sinus floor were observed.

Relationship of the maxillary posterior teeth and maxillary sinus floor in different skeletal growth patterns: A cone-beam computed tomographic study of 1600 roots

Purpose

This study evaluated the distance from the posterior root apices to the maxillary sinus floor (MSF) and the frequency of roots touching or protruding through the MSF using cone-beam computed tomography (CBCT).

Materials and Methods

This study included 100 subjects divided into different vertical and anteroposterior skeletal growth patterns. On CBCT images, the distance from the posterior root apices to MSF was measured and the frequency of roots touching or protruding through the MSF was evaluated using NNT software (version 5.3.0.0; ImageWorks, Elmsford, NY, USA).

Results

No statistically significant differences were found in the distance from the posterior root apices to the MSF among vertical skeletal groups (P>0.05). The palatal roots of the first molar and the palatal, mesio-buccal and disto-buccal roots of the second molars had significantly less distance from MSF in skeletal class II than in class III (P<0.05). The high-angle group had the highest frequencies of roots touching or protruding into the maxillary sinus (49.8%); the lowest proportion of these roots was found in skeletal class III (28.3%) and the highest proportion in class II (50.3%). Males had shorter distances from the posterior root apices to the MSF and higher frequencies of roots protruding through or touching the MSF than females.

Conclusion

Anteroposterior skeletal growth patterns and sex affected the distances from the maxillary posterior roots to the MSF. The frequency of roots protruding into or touching the sinus was affected by both vertical and anteroposterior skeletal groups and sex. These findings have implications for dental practice.

Effect of sinus proximity, alveolar bone level, and initial buccolingual inclination on behavior of maxillary first molar under expansion force: a finite element analysis

BACKGROUND

The primary aim of this study is to determine whether sinus proximity increases or decreases molar tipping under the force of expansion; a secondary aim is to compare the effect of the initial buccal inclination, alveolar bone loss, and sinus proximity to molar movement under expansion force, by assessing the stress distribution of the periodontal ligament and the changes in the moment/force (M/F) ratio).

METHODS

Twenty different 3-dimensional models were created by changing the buccal inclination (0°,5°,10°,15°, and 20°) value of maxillary molar and simulating different amounts of alveolar bone loss (0, 2,4, and 6 mm) in the basic model. Additionally, an artificial sinus was added to the basic model, and the penetration of the roots into the sinus to different levels (2, 4, and 6 mm) was simulated separately. Thus, 9 additional models were created. The M/F ratio, location of the center of resistance, and principal stresses on the periodontal ligament were analyzed for each of the 29 models separately in a finite element analysis.

RESULTS

The M/F ratio increased as initial buccal inclination or bone loss increased. As the amount of simultaneous penetration of 3 roots into the sinus increased, the M/F ratio decreased. Incremental changes of both the initial inclination value and the amount of bone loss resulted in higher maximum compressive stress on the apices of the buccal roots.

CONCLUSIONS

Increases in alveolar bone loss and buccal inclination caused increases in the periodontal stress. Penetration of the roots into the sinus provides bicortical anchorage and could prevent unwanted crown tipping.

Vertical relationships between the divergence angle of maxillary molar roots and the maxillary sinus floor: A cone-beam computed tomography (CBCT) study

AIM

To assess the relations between the divergence angle of the maxillary molar roots and their proximity to the maxillary sinus floor using CBCT.

METHOD

This study comprised CBCT scans of the maxilla, including at least the inferior one-third of the maxillary sinus and at least one molar present in any quadrant with complete eruption and root formation. Evaluation included the vertical relations between the maxillary molar root apices and the maxillary sinus floor (MSF), and the root divergence was measured from the root apices to the floor of the pulp chamber. The chi-square test was used for the associations between the study parameters. For the correlation between root divergence angles and MSF vertical relationship types, the Spearman test was used. A P-value < 0.05 was considered significant.

RESULTS

A total of 100 scans were analyzed, including 316 permanent maxillary first and second molars. The MSF Type II vertical relationship was the most prevalent (39.6%), followed by Type I (31.3%). The highest divergence angle was found between the distobuccal and palatal roots (mean = 44.9 ± 10.5°). For the mesiobuccal-distobuccal angle groups, there were higher percentages of the MSF Type I and II relationships among the angle groups < 1° and 21-45°. For the mesiobuccal-palatal angle groups, a higher prevalence of the MSF Type II relationship was found in the <21⁰ and >45⁰ angle groups, and a higher prevalence of the Type I relationship was found in the 21-45⁰ angle group. For the distobuccal-palatal angle groups, higher percentages of the MSF Type II relationship were found in the three angle groups. For all teeth, there was a significant positive correlation between the MSF vertical relationship and the mesiobuccal-palatal angle (r = 0.116; P = 0.039).

CONCLUSION

There was a positive correlation between the divergence angle of the roots and their vertical relationship with the MSF. Clinicians should assess the divergence between the roots before performing extraction or endodontic treatments.

Intrusion of maxillary molar roots into the maxillary sinus in a sample of the Egyptian population using cone beam computed tomography

Background

The proximity of the maxillary sinus floor to the maxillary molar roots increases the probability of oroantral communication on conducting any surgical or endodontic procedure in the involved area. The aim of this study is to evaluate the relationship between each maxillary molar root and maxillary sinus floor using cone beam computed tomography. Predicting the probability of protrusion of each root into the sinus will consequently predict the probability of occurrence of the oroantral fistula in a sample of the Egyptian population.

Results

The total number of roots located outside the sinus was 121 (35.3%), while those contacting the sinus floor were 80 (23.3%) and those intruded the sinus were 141 (41.2%). The percentage of root intrusion into the sinus in males (56.9%) was significantly (p = 0.01) higher than females (42.9%). The probability of root intrusion in the left molars (54.2%) was non-significantly (p = 0.067) higher than that of the right side (44.3%). As for the type of tooth, the second molar showed the highest probability of root intrusion into the sinus (55.3%) followed by the third molars (52.6%) then the first molars (40.9). According to the type of root, the mesiobuccal root showed the highest probability of intrusion into the sinus (50.9%) followed by the palatal root (49.1%) then the distobuccal root (47.4%). However, the difference in both type of tooth and type of root was statistically non-significant (p = 0.051 and 0.869 respectively). As for the individual root with the highest probability of intrusion, the mesio-buccal root of the right third molar is the most frequent root to intrude the sinus (71.4%) and the mesio-buccal root of the right first molar is the least frequent (22.7%).

Conclusions

In a sample of the Egyptian population, males exhibit higher probability of root protrusion into the sinus than females. The side and type of tooth are of higher impact on the probability of its intrusion into the sinus compared to the type of root. Left second molars are at a higher risk of oroantral communications on surgical or endodontic procedures compared to other molars due to its highest probability of intrusion into the sinus.

CBCT-based assessment of the anatomic relationship between maxillary sinus and upper teeth

Objectives

To describe the relationship between maxillary sinus (MS) and upper teeth based on cone beam computed tomographic scans (CBCT).

Materials and methods

Based on CBCT maxillary imaging data of 147 patients, distance between MS and apices of canines and posterior maxillary teeth were assessed. Distances between tooth roots and sinus were classified into three groups: distant (>2 mm), close (<2 mm) or in contact with MS. Teeth with apical lesions and uncommon root configurations were excluded.

Results

In total, 1075 teeth of maxillary canines, upper premolars and upper molars were included in this study. Teeth most often in contact with MS were the second (89%) and first (81%) maxillary molar without any significant difference (p = 0.19). Roots most often in contact with MS were the mesiobuccal and distobuccal root of the second molar (85% and 76%; p = <0.01) followed by the palatal root of the first molar (73%). A fifth of the upper canines are situated less than 2 mm from MS.

Conclusions

More than four out of five upper molars (first and second) are in a close relationship to the MS. Knowledge of the anatomical relationship between posterior maxillary teeth and the MS is important for diagnosis and treatment in this area.

Relationship between maxillary posterior molar roots and the maxillary sinus floor: Cone-beam computed tomography analysis of a western Chinese population

OBJECTIVE

This study aimed to assess the positional relationships between the maxillary sinus and the first and second molars in a western Chinese population by using cone-beam computed tomography.

METHODS

This study included 212 patients (652 maxillary molars and 1956 roots). Patient demographics (sex and age) and cone-beam computed tomography data regarding the relationship between molar roots and the maxillary sinus were obtained. This relationship was stratified into four types for statistical analysis.

RESULTS

Sex and side did not significantly influence the distance between maxillary molar roots and the maxillary sinus. However, the distance between maxillary molar roots and the maxillary sinus increased with age. The mesiobuccal root of the second molar was nearest to the maxillary sinus. The most common relationship type involved absence of root contact with the sinus border and presence of a maxillary sinus cross-section above the root apex.

CONCLUSIONS

Compared with other teeth, the maxillary posterior teeth have a complex anatomical structure and are closely related to the sinus. These findings may serve as reference information for root canal treatment, tooth extraction, dental implant, and other dental clinical procedures among patients in western China.

Specific oral and maxillofacial identifiers in panoramic radiographs used for human identification

Radiographically assisted dental identification is an important means for individual identification. Specific identifiers help to quickly filter some of the possible corresponding AM and PM images at the beginning. The study seeks specific oral and maxillofacial identifiers in panoramic radiographs. A total of 920 panoramic radiographs from 460 live patients were used. The most recent radiograph served as the surrogate post-mortem (PM) record of an unidentified person, and the earliest radiograph served as the ante-mortem (AM) record of the same person. We evaluated the following four groups of identifiers of the images: (1) dental morphology, tooth number, and position; (2) dental treatment and pathology; (3) morphological identifiers of the jaw; and (4) pathological identifiers of the jaw. The ratio of each identifier being identified simultaneously in the AM and PM databases was determined. Specific identifiers were defined as those that appeared at low frequency (ratio: 0%-0.250%). A total of 18 specific oral and maxillofacial identifiers were determined. The specific identifiers were a retained deciduous tooth (0.011%), S-shaped deflection of a tooth root (0.012%), distal deflection of tooth root (0.017%), inverted impaction (0.018%), malposition (0.038%), supernumerary teeth (0.061%), mesial deflection of tooth root (0.092%), microdontia (0.136%), buccal/lingual impaction (0.188%), cementoma (0.002%), hypercementosis (0.002%), continuous crown (0.004%), pulp calcification (0.023%), attrition (0.030%), residual root (0.106%), root resorption (0.137%), implant (0.156%), and osteomyelitis (0.002%). Identifiers of the teeth and jaw can be used for human identification, and dental identifiers are more specific than identifiers of jaw.

Comparison of panoramic radiography and cone-beam computed tomography for assessing radiographic signs indicating root protrusion into the maxillary sinus

Purpose

This study investigated correlations between findings on panoramic radiographs and cone-beam computed tomography (CBCT) to assess the relationship between the maxillary sinus floor and the roots of maxillary posterior teeth. In addition, radiographic signs indicating actual root protrusion into the maxillary sinus were evaluated on panoramic radiographs.

Materials and Methods

Paired panoramic radiographs and CBCT images from 305 subjects were analyzed. This analysis classified 2,440 maxillary premolars and molars according to their relationship with the maxillary sinus floor on panoramic radiographs and CBCT images. In addition, interruption of the sinus floor was examined on panoramic radiographs.

Results

Root protrusion into the maxillary sinus occurred most frequently in the mesiobuccal roots of the second molars. The classification according to panoramic radiographs and CBCT images was the same in more than 90% of cases when there was no contact between the root apex and the sinus floor. When the panoramic radiograph showed root protrusion into the sinus, the CBCT images showed the same classification in 67.5% of second molars, 48.8% of first molars, and 53.3% of second premolars. There was a statistically significant relationship between interruption of the sinus floor on panoramic radiographs and root protrusion into the sinus on CBCT images.

Conclusion

The presence of root protrusion into the sinus on panoramic radiographs demonstrated a moderate ability to predict root protrusion into the maxillary sinus. Interruption of the maxillary sinus floor could be considered an indicator of actual root protrusion into the maxillary sinus.