A cone-beam computed tomographic assessment of the proximity of the maxillary canine and posterior teeth to the maxillary sinus floor: Lessons from 4778 roots

Anatomical relationship between maxillary posterior teeth and the maxillary sinus in an Indonesian population: a CT scan study

BACKGROUND

The anatomical proximity between the root apex of the maxillary posterior teeth and the maxillary sinus can lead to complications, including odontogenic maxillary sinusitis. While several studies have investigated similar variables in different populations, there is limited research on the Indonesian population. This study aimed to describe the anatomical position of the maxillary posterior teeth in relation to the floor of the maxillary sinus using CT scans.

METHODS

A total of 122 patients (432 maxillary premolars and 1,282 maxillary molars) underwent CT scans to evaluate 1,711 roots. The vertical relationship between the root apex of the maxillary posterior teeth and the maxillary sinus was classified into three types: IS (inside sinus), CO (sinus contact), and OS (outside sinus).

RESULTS

The IS type was predominantly found in the palatal roots of the first molars, accounting for 20% of the total roots in this type. The CO type was most frequently observed in the mesiobuccal roots of the second molars, representing 18% of the total roots in this type. The OS type was most commonly found in the first premolar, comprising 20% of the total roots in this type.

CONCLUSIONS

The palatal roots of the first molars exhibited the highest frequency of proximity to the maxillary sinus. CT scans can effectively assess the relationship between the root apex of the posterior teeth and the maxillary sinus.

CLINICAL RELEVANCE

Clinicians should consider this information comprehensively when planning treatments for maxillary molars.

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.

Does maxillary sinus proximity affect molar root resorption during distalization using Invisalign? a CBCT study

BACKGROUND

This study aimed to assess the correlation between maxillary sinus proximity to root apices of maxillary molars and root resorption during molar distalization using clear aligner therapy (CAT).

MATERIALS AND METHODS

Thirty-eight cone beam computed tomography scans (CBCTs) obtained pre- (T0) and post-treatment (T1) from 19 adult patients (36.68 ± 13.50 years), who underwent maxillary molar distalization using Invisalign® aligners (Align Technology, Inc., San José, CA, USA) with a minimum of 2 mm distalization, were evaluated in this study At least 22 h of aligner wear per day was a main inclusion criterion. Sinus proximity and changes in root lengths were measured for 61 molars (183 roots). Spearman coefficient analysis was used for assessing correlation between sinus proximity and root resorption. The level of significance was set at p ≤ 0.05. The reproducibility of measurements was assessed by intraclass correlation coefficient (ICC).

RESULTS

Spearman coefficient revealed no significant correlation between sinus proximity and molar root resorption for mesiobuccal, distobuccal or palatal roots (p = 0.558, p = 0.334, p = 0.931, respectively).

CONCLUSION

There was no correlation between maxillary sinus proximity to root apices of maxillary molars and root resorption.

Three-dimensional evaluation of maxillary sinus volume, skeletal and dentoalveolar maxillary anterior region, in unilateral palatally impacted maxillary canine (Cross-sectional study)

OBJECTIVES

Three-dimensional evaluation of maxillary sinus volume using VR mesh and correlate it with the volume of maxillary canine, lateral incisor, and dentoalveolar and skeletal dimensions in both impacted and non-impacted sites.

MATERIALS AND METHODS

In a retrospective cross-sectional study, cone beam computed tomography scans of 100 patients with unilateral palatally impacted maxillary canine were analyzed. Canine, lateral incisor, and maxillary sinus volumes on the impaction and non-impaction sides were measured using DICOM files, with three-dimensional softwares (MIMICS) and VR mesh to accomplish this assessment.

RESULTS

There were no significant differences in canine and lateral incisors volumes between male and female patients in the impacted side at (p > 0.05) while the maxillary sinuses volume revealed a statistical difference (P = 0.022) between male (12642 ± 810) and female (12481 ± 650) patients in the impacted side. A strong positive correlation was found between canine and lateral incisor volume for male patients in the non-impacted (r = 0.420**, P = 0.008) and impacted sides (r = 0.334*, P = 0.038).

CONCLUSIONS

There were no significant differences in the canine volume, the height of the anterior alveolar ridge (AARHMLI), and anterior dentoalveolar (ADAHMLI) of maxillary lateral incisors in the impacted/non-impacted side, but it showed a statistically significant difference for the lateral incisors volume in the impacted and non-impacted sides for male and female patients. The maxillary sinus volumes revealed a statistical difference between males and females in impacted and non-impacted sides.

[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.

Does the floor of the maxillary sinus affect tooth movement for premolar extraction space closure?

OBJECTIVE

The study investigated orthodontic tooth movement by comparing various horizontal and angular measures of the teeth having different sinus-root relationship (SRR) of patients undergoing first premolar extraction treatment protocols.

MATERIALS AND METHODS

This retrospective cross-sectional study included 45 Taiwanese adult patients, classified as the control group (n = 15) and the sinus group (n = 30) according to SRR. The control group had type I SRR (sinus floor above the level connecting the buccal and palatal root apices), whereas the sinus group included patients with type V SRR (the buccal and palatal root displayed apical protrusion into the sinus floor). Morphology was identified using pretreatment orthopantomograms. Lateral cephalometric measurements were conducted before treatment (T1) and at debonding (T2).

RESULTS

Post debonding, there were no statistically significant difference in the two groups. However, the incisors in the control group became marginally more upright than those of the sinus group, and the molars demonstrated tipping movement with minimal anchorage loss in the sinus group than in the control group. The total treatment time was not significantly different between the 2 groups.

CONCLUSION

The study revealed that the sinus-root relationship does not affect the orthodontic tooth movement. However, a more extensive 3-D study with larger sample size is strongly recommended before coming to any conclusion.

CLINICAL RELEVANCE

The lining of the floor of the maxillary sinus does not affect the orthodontic tooth movement.

Factors associated with the eruption of the impacted maxillary third molars after second molar extraction

INTRODUCTION

In orthodontic treatment, the space left after extracting the maxillary second molar (MxM2) may be filled by the eruption of the impacted third molar (MxM3). However, little is known about the factors associated with the eruption of the impacted MxM3. We aimed to characterize the clinical factors associated with the time taken for MxM3 eruption after MxM2 extraction.

METHODS

We analyzed factors associated with late MxM3 eruption (>500 days after MxM2 extraction) in 84 molars. Prespecified risk factors were entered into logistic regression models to estimate odds ratios (ORs).

RESULTS

The median duration between MxM2 extraction and MxM3 eruption was 302 days (interquartile range, 140-424). Significant factors associated with late MxM3 eruption included the proximity of the MxM3 root to the maxillary sinus floor (OR, 51.72), the distance between the occlusal plane of the MxM3 and the apical third of the MxM2 roots (OR, 16.56), MxM3 angulation and depth of ≥20° (OR, 5.58), ANB angle of <2° (OR, 9.05), and ≥1.5 mm distal movement of the maxillary first molar (MxM1) from its original position at the time of MxM2 extraction and MxM3 eruption (OR, 12.9). The probability of late MxM3 eruption was 0% (0 out of 30) with no risk, 6.9% (2 out of 29) with 1 risk factor, and 52% (13 out of 25) with ≥2 risk factors.

CONCLUSIONS

We identified 5 clinical factors associated with late MxM3 eruption after MxM2 extraction. The probability of late MxM3 eruption increased as the number of present risk factors increased. These findings can be used for risk stratification during orthodontic 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.

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.

Assessment of the relationship between the maxillary sinus and the canine root tip using cone beam computed tomography

BACKGROUND

The purpose of the present study is to investigate the relationship between the maxillary sinus and the canine root apices in cone beam computed tomographic images (CBCT) and to assess the amount of extension of the maxillary sinus to the anterior region of the jaw in different sexes and age groups.

METHODS

CBCT of 300 individuals (154 males and 146 females) over 20 years (with a mean age of 35.12 ± 8.40 years) were evaluated. The subjects were categorized into three age groups (20-30, 30-40, and 40-50 years). When the maxillary sinus extended to the canine area, the vertical distance between them was measured, and their relationship was classified into three types: I (more than 2 mm distance), II (less than 2 mm distance or in-contact), and III (interlock).

RESULTS

413 out of 600 maxillary sinuses (68.8%) were extended into the canine area or beyond. Among them, 15 maxillary sinuses pneumatized into the incisor area (2.5%). The prevalence of the maxillary sinuses extended to the anterior region of the jaw was not significantly different between genders. However, it was significantly less frequent in the older age group and more frequent on the left side. In addition, the mean amount of anterior extension of the maxillary sinus (mm) was significantly lower in the older age group. Type I was the most frequent vertical relationship between the maxillary sinuses and canine apices with no significant difference in gender, side, and age groups.

CONCLUSIONS

In most cases, the maxillary sinus extended to the canine area and sometimes reached the incisor region. This necessitates paying more attention to the maxillary anterior sextant during surgical procedures.

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.

Should the "envelope of discrepancy" be revised in the era of three-dimensional imaging?

Since their introduction in the field of orthodontics, temporary anchorage devices (TADs) have been widely applied in the treatment of cases that have proven difficult to treat using conventional methods. Although TADs have broadened the scope of orthodontic treatment by modifying the envelope of discrepancy, whether they represent the ultimate solution in all cases remains controversial. Cone-beam computed tomography (CBCT) has recently been used to obtain three-dimensional images of the craniofacial skeleton and teeth. Thus, CBCT has clarified the three-dimensional morphology/configurations of structures that cannot be appropriately visualized using conventional imaging (i.e., cephalometric and panoramic radiographs). These structures include the incisive canal and maxillary sinus. In this review, I highlight the importance of understanding the mutual relationship between the roots of the maxillary teeth and these structures for diagnosis and treatment planning, as well as potential need to revise the envelope of discrepancy.