Space closure in the maxillary posterior area through the maxillary sinus

Anatomical factors of the maxillary tuberosity that influence molar distalization

Objective

To examine the areas of the maxillary tuberosity (MT) (coronal, apical, width, and height) with respect to the presence or absence of the third molar to establish possible anatomical limitations for molar distalization.

Methods

A total of 277 tuberosities were evaluated through sagittal computed tomography (CT) images, divided for measurement into coronal (free of bone), apical (area of influence of the maxillary sinus), and tuberosity (bony area) zones, and stratified by the presence or absence of the third molar, sex, and two age subgroups. Mann-Whitney U test was used to compare the groups considering the third molar.

Results

The medians of the width and height of the tuberosity decreased significantly in the absence of the third molar (P < 0.001). The apical area also showed differences, with negative values in the absence of the third molar and positive values in the presence of the third molar (P < 0.001). However, no differences were observed for the coronal area (P > 0.05).

Conclusions

In the absence of the third molar, the size of the MT, represented by its width and height, was smaller and negative values (decrease) were observed for the maxillary sinus. The sagittal CT provides useful information regarding the amount of bone tissue available for distalization and relationship of the second molar with respect to the maxillary sinus, which allows individualizing each case in relation to the amount and type of movement expected.

Non-compliance treatment in a young adult full-step class II division 2 malocclusion with preadjusted lingual appliance and upper first molars extractions

This case report describes a complex full-step class II case in a young adult patient treated with lingual straight-wire appliance and upper first molar extraction. As the patient refused a surgical treatment, she was offered the best possible camouflage with the double aim of obtaining an ideal occlusal relationship and maintaining the profile; appropriate biomechanical strategies, including extraction choice and anchorage control during space closure, were needed to achieve the planned results. This case report demonstrates the possibility of successfully resolving severe sagittal discrepancies in an adult patient without surgical treatment by means of a completely invisible non-compliance technique, with the extraction of the most compromised teeth. This report also underlines the need for careful planning during both diagnostic and treatment phases, in order to obtain the best results.

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.

Evaluation of changes in the maxillary sinus of orthodontic patients with maxillary molar distalization using cone-beam computed tomography

INTRODUCTION

This study aimed to evaluate the possible effects of maxillary molar distalization on maxillary sinus mucosa thickness and sinus volume in 3-dimensions.

METHODS

The study was conducted with 46 patients: 73.9% (n = 34) females and 26.1% (n = 12) males. The patients had a mean age of 27.89 ± 6.62 years, ranging from 18 to 45 years. The study included patients who were admitted to the Faculty of Dentistry at Van Yüzüncü Yıl University between 2010 and 2021 and underwent cone-beam computed tomography (CBCT) before and after orthodontic treatment for various reasons. The CBCT scans of patients were divided into 2 groups: the first group underwent orthodontic treatment and maxillary molar distalization with Class II elastic, whereas the second group consisted of patients who did not get orthodontic treatment (control). In CBCTs, sinus mucosa thickness was measured on the anterior, posterior, medial, lateral, superior, and inferior walls of the maxillary right and left sinuses. Three-dimensional volume calculations were made using CBCT images taken before and after the treatment of both orthodontic treatment patients and control patients. Statistical significance was set at P <0.05.

RESULTS

The orthodontic treatment group had a mean distalization of 2.86 ± 0.27 mm. The mean distalization time was 8.01 ± 0.64 months. When the differences between the pretreatment and posttreatment CBCT scans were examined in terms of sinus mucosa thickness in the anterior, posterior, medial, lateral, and superior walls of the right and left sinuses, there was no statistically significant difference between treatment and control groups (P >0.05). The change in sinus mucosa thickness in the right and left sinus inferior wall from T1 to T2 was significantly higher in the control group than treatment group (P <0.05). In addition, the increase in maxillary sinus volume was statistically significantly higher in the treatment group than in the control group (P <0.05).

CONCLUSIONS

We observed that maxillary molar distalization caused an increase in maxillary sinus volume. The change in sinus mucosa thickness in the right and left sinus inferior wall was lower in the maxillary molar distalization group.

Three-dimensional evaluation of the maxillary sinus in patients with different skeletal classes and cranio-maxillary relationships assessed with cone beam computed tomography

The objective was to evaluate the relationship between the dimensions of the maxillary sinuses (MSs) and various cephalometric parameters. MS volume (MSV), MS surface (MSS), linear maximum depth (LMD), linear maximum width (LMW), and linear maximum height (LMH) were calculated on CBCT scans of 99 adults. Two sets of two-way (ANOVA) assessed the influence respectively of ANB and SNA angles and of the gender on MS dimensions. Pearson's correlation was calculated between MS dimensions and different cephalometric variables. Reliability and accuracy of the proposed method was tested with intra-operator and inter-operator intraclass correlation coefficient (ICC). Two-way ANOVA showed no statistically significant difference in MSV, MSS and LMH between ANB groups, whilst males were associated with bigger sinuses. LMW showed statistically significant difference in both ANB and gender groups. LMD showed no statistically significant difference. The second Two-way ANOVA showed significantly larger MSV, MSS and LMD in patients with increased or reduced SNA angle but not between genders. LMW and LMH also showed a significant difference between genders. All linear measurements showed a significant interaction of the two factors. The intra-observer and inter-observer ICC scored high for all the tested measurements. MSV and MSS showed a positive correlation with S-N, PNS-A, S-Go, N-Me, N-Ans and the distance between Mx points. LMW had a negative correlation with Ba-S-N angle and N-Me, LMH with Ba-S-N angle, S-Go and Mx r-Mx l and LMD with N-Me and N-ANS. LMW had a positive correlation with Mx r-Mx l, LMH with S-N, S-N^Ans-Pns, N-Me, N-Ans and LMD with S-N, Ba-S-N, PNS-A, S-Go and distance between Mx points. In conclusion, MSV and MSS did not differ between the three skeletal classes, males showed significantly larger MS than in females. Concerning the influence of the cranio-maxillary relationship (SNA) and gender on MS dimension, subjects with a retrusion (SNA < 80°) or protusion (SNA > 84°) of the maxillary alveolar bone had larger MSV, MSS, LMW, LMH and LMD than subjects with a normal cranio-maxillary relationship (SNA 82 ± 2°). A statistically significant high positive correlation was observed between S-N, Pns-A, S-Go, Mx-R/Mx-r and MS dimension. Further studies that evaluate similar outcomes in different races may be able to enrich our knowledge on this topic.

A comparison of maxillary sinus diameters in Chinese and Yemeni patients with skeletal malocclusion

BACKGROUND

This study aimed to compare the maxillary sinus dimensions and surface area in accordance with skeletal malocclusion, gender and ethnicity factors in a sample of Chinese and Yemeni patients.

METHODS

This cross-sectional study analysed 180 maxillary sinuses using 180 lateral cephalometric radiographs. The patients were subdivided into two ethnic groups: Chinese and Yemeni. Each ethnic group comprised 90 patients, and men and women were divided equally. Each ethnic group was classified into three skeletal classes using ANB and Wits appraisal (skeletal Classes I, II and III). Pearson's correlation coefficient was also used to assess the relationship between maxillary sinus dimensions and cephalometric parameters.

RESULTS

Men had larger maxillary sinuses than women; skeletal Class II had a higher length and surface area increase than other skeletal classes, although skeletal Classes I and II were almost equal in height. Except for the maxillary sinus length, none of these findings were statistically significant. The maxillary sinuses in Chinese are larger than those in Yemenis (P = 0.000). These variables were positively correlated with SNA, SNB and Co-A. The maxillary sinus length and Co-Gn were positively correlated. The NA-APO and NA-FH angles were also correlated with the maxillary sinus surface area. However, the gonial and GoGn-Sn angles negatively affected the maxillary sinus dimension and surface area.

CONCLUSIONS

Men had larger maxillary sinuses than women in both ethnic groups, and Chinese individuals had larger maxillary sinuses than Yemenis. Skeletal Class II malocclusion of both ethnicities had larger maxillary sinus dimensions. Furthermore, the maxillary sinus dimensions correlated with cephalometric parameters.

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.

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.

'Comparison and correlation of the maxillary sinus dimensions in various craniofacial patterns: A CBCT Study'

Background: To compare and correlate the maxillary sinus dimensions and basal bone height among various facial patterns using CBCT for advanced diagnosis and treatment planning in Orthodontics.

Methods: 66 CBCT images within age group of 18-30 years were divided into horizontal (Group 1), average (Group 2) and vertical (Group 3) facial growth patterns. Maxillary sinus dimensions were compared and correlated in all three groups. The sinus height and basal bone height were recorded at 3 locations-between 1 ^st premolar and 2 ^nd premolar (PM1-PM2), between 2 ^nd premolar and 1 ^st Molar (PM2-M1) and between 1 ^st and 2 ^nd molar (M1-M2).

Results: Overall reduction in sinus height and significantly reduced sinus volume was seen in Group-1. Longest maxillary sinus height in M1-M2 region and shortest in PM1-PM2 region was seen in Group-3. The basal bone height in PM1-PM2 region was significantly longer in Group-3 than in Group-1(p<.05).Shortest basal bone height in M1-M2 region was seen in Group-3. A significant negative correlation was seen between the maxillary sinus height and the basal bone height in Group-1 and Group-3(p<.05).

Conclusion: There is a correlation between the maxillary sinus height and basal bone height with that of facial pattern which needs to be considered during orthodontic treatment planning and while carrying out facial growth modification procedures in younger patients.

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.

Space closure by miniscrew-assisted mesialization of an upper third molar and partial vestibular fixed appliance: A case report

This case report demonstrates how the use of skeletal anchorage and appropriate orthodontic biomechanics can be used to resolve even complex cases, reducing unwanted dental movements and allowing the use of a partial vestibular appliance. It describes the complete mesialization of the left upper third molar and space closure following extraction of tooth UR7, due to vertical fracture one year after previous endodontic therapy for caries. This therapeutic choice was conditioned by the need not to alter the good pre-existing interarch relationships, and above all by the patient's request to be treated conservatively, and therefore not to undergo prosthetic implant rehabilitation. The use of orthodontic miniscrews and the careful application of orthodontic biomechanics, based on both direct and indirect anchorage, enabled the treatment objectives to be achieved in a reasonable period of time with reduced treatment costs.

Molar space closure: To do or not to do?

Missing or compromised permanent molars can complicate orthodontic treatment planning and mechanics. Molar extraction should be considered in appropriate situations, but clinicians must decide between closing and regaining the edentulous space. Several factors should be taken into consideration to achieve appropriate molar space management, such as the need for space, asymmetry, periodontal status, sinus pneumatization, and the terminal molar position. Herein, three sample cases are reported to demonstrate the treatment options for molar space closure and maintenance with these factors taken into consideration during treatment planning. The understanding of mechanics played a crucial role in anchorage preparation and side effect prevention. If the third molar substitution was managed in advance and adequate space between the ramus and third molar was obtained via second molar protraction, the tooth spontaneously erupted in a favorable position without requiring further treatment. This case series can aid clinicians in molar space management. Regardless of whether the space is to be closed or regained, the treatment plan should conform to the patient’s expectations and improve occlusion with minimal side effects and treatment duration.

Evaluation of the distance between the root apices of the upper first molars and the hard palate in an Eastern Mediterranean population: A retrospective study

OBJECTIVE

The aims of this retrospective study were, first to evaluate the distance between the root apices of the upper first molars and the palatal plane (PP), and second to determine the validity (accuracy) of the use of cephalometric radiographs or panoramic X-rays compared to cone beam computed tomography (CBCT) in determining this distance.

MATERIAL AND METHODS

The distance was calculated from the root apices of the first molars to PP, on the cephalometric radiographs of 204 subjects and then 57 measurements were compared to those obtained on panoramic X-rays and CBCT images, in order to find a statistically significant difference according to age, sex, side, vertical and sagittal skeletal patterns, and to determine if 2D radiographs are suitable for this task.

RESULTS

The distance increased significantly in subjects after 20 years of age and in hyperdivergent patients, but was not influenced by sex, side or anteroposterior position of the mandible. No statistical significance was found between the calculated measurements on cephalometric and CBCT radiographs, but both were different from those taken on panoramic X-rays.

CONCLUSIONS

Cephalometric radiographs are reliable in the assessment of the distance between the roots of the upper molars and the PP. In hyperdivergent and adult patients, posterior teeth have enough space between their roots and the upper limit of the hard palate to undergo intrusion mechanics using miniscrews, but care must be taken while planning and managing these movements in order to minimize the unwanted side effects.

Evaluation of maxillary sinus volume in different craniofacial patterns: a CBCT study

INTRODUCTION

Few studies have compared the relationship of MSV in the different craniofacial patterns. Hence, the purpose of this research was to evaluate maxillary sinus volume in different craniofacial patterns using cone-beam computed tomography.

MATERIALS AND METHODS

This cross-sectional study included 100 pre-orthodontic patients mean aged 26.40 ± 6.77 (age ranged 21-64) years divided into different anteroposterior and vertical skeletal groups. From the cone beam computed tomography images using MIMICS 14.1 software, three-dimensional image of the maxillary sinus was constructed, and its volume was calculated.

RESULTS

The mean maxillary sinus volume was 20,279.50 ± 7800.33 mm³. Among the anteroposterior skeletal groups, the mean maxillary sinus volume in skeletal Class II group is significantly larger than class III group (P < 0.05). Among the vertical skeletal groups, High-angle groups tend to have the largest maxillary sinus volume, though there were no significant differences among the groups (P > 0.05). Similarly, males have significantly larger maxillary sinus volume than females (P < 0.05). There was a positive correlation between ANB and maxillary sinus volume (P < 0.01).

CONCLUSION

Maxillary sinus volume is significantly larger in skeletal class II than in skeletal class III group and in males than in females (P < 0.05). These inferences have several implications in orthodontics, endodontics and oral surgery.

Multidisciplinary management of permanent first molar extractions

The first molar has been reported to be the most caries prone tooth in the permanent dentition. Orthodontists are treating more adult patients who are more likely to have missing and severely decayed first molars. This article will show the various orthodontic and restorative options for first molars that are already extracted or have to be extracted. The following clinical situations will be addressed: molar uprighting and its advantages for the future restoration vs orthodontic space closure, strategic extraction of salvable first molars, impacted molars, and early extraction of compromised permanent first molars in young children.

Evaluation of the Relationship Between Maxillary Sinus Wall and Maxillary Canines and Posterior Teeth Using Cone-Beam Computed Tomography

Background

The proximity between the maxillary sinus and dental roots may impede orthodontic tooth movement. This study aimed to explore the relationship between the maxillary sinus wall (MSW) and maxillary canines and posterior teeth using cone-beam computed tomography (CBCT).

Material/Methods

CBCT images (317) were examined for whether the mesial, distal, buccal, and palatal surfaces of the examined root contacted the MSW, and the contact distance of each root surface with the MSW was measured. The effects of age and sex were analyzed using logistic regression and linear regression analyses.

Results

The highest contact ratios with the MSW (ranging from 62.0% to 73.2%) were observed at the palatal root surfaces of the first molar mesiobuccal and distobuccal roots (1M MB and DB), the buccal root surface of the first molar palatal roots (1M P), and the mesial and buccal root surfaces of the second molars (2M), followed by the distal root surface of the second premolars (2PM) and the mesial root surfaces of the 1M MB and P (ranging from 49.2% to 59.3%). At these root surfaces, the contact ratios decreased with age (P<0.05), but the lowest still reached a range of 29.4% to 57.9% in the 30- to 47-year-old group.

Conclusions

The 2PM distal root surface, the 1M MB mesial and palatal root surfaces, the 1M DB palatal root surface, and the 1M P and 2M mesial and buccal root surfaces most frequently contacted the MSW. Clinicians should observe the contact of root surfaces with the MSW, even in aged patients.

Lateral and apical root resorption in teeth orthodontically moved into edentulous ridge areas

Objective:

The present study aimed at comparing the external lateral root resorption (ELRR) and external apical root resorption (EARR) between teeth moved through the atrophic edentulous ridge and those undergoing the usual orthodontic movement.

Methods:

Fifty-four premolars were evaluated, where 27 of them had been moved toward the edentulous ridge (Group 1) and 27 from the same patient, had not been translated, which comprised the control group (Group 2). ELRR was evaluated by 0-3 scores and EARR was evaluated by 0-4 scores, before and after movement. Measurements were compared by Kruskal-Wallis and Student-Newman-Keuls tests.

Results:

ELRR increased statistically only in the Group 1 (p< 0.05). After orthodontic treatment, it was observed that almost 56% (n = 15) of teeth in Group 1 presented scores 2 and 3, while Group 2 presented scores 2 and 3 in about 11% (n= 3) of the teeth. EARR increased in both groups after orthodontic movement, however, statistically analyses showed no significant differences between groups (p> 0.05).

Conclusions:

Orthodontic movement into the atrophic edentulous ridge is subject to a greater lateral external root resorption.

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

INTRODUCTION

When tooth roots protrude into the maxillary sinus, apical root resorption and tipping may occur during horizontal tooth movement across the sinus floor. Three-dimensional cone-beam computed tomography (CBCT) images may provide detailed information without distortion and overlap. We evaluated the relationships between the maxillary tooth root apices and the maxillary sinus floor using CBCT.

METHODS

We evaluated 4778 roots from 76 men (aged 27.6 ± 10.4 [mean ± standard deviation] years; range, 18-69 years), and 225 women (aged 30.4 ± 12.0 years; range, 18-68 years). The positional relationships between the maxillary tooth root apices, including the canine, premolar (first and/or second), and molar (first and/or second), and the inferior wall of the maxillary sinus were comprehensively evaluated on 2 cross-sectional CBCT images (ie, the sagittal and coronal planes). These distances were measured in both images simultaneously.

RESULTS

The sagittal plane distances were significantly larger than coronal plane distances, except for the distobuccal root of the first molar. Pearson correlation test revealed a significant negative correlation between the distance and the patient's age.

CONCLUSIONS

Our study provides valuable information for planning orthodontic tooth movement through the maxillary sinus, which may help to predict the occurrence and severity of root resorption.

Prevalence and morphological variations of maxillary sinus septa in different age groups: a CBCT analysis

BACKGROUND

There are limited data from Saudi Arabia on the prevalence and characteristics of maxillary sinus septa.

OBJECTIVE

Determine the prevalence and morphological characteristics of septa in the maxillary sinus and their relationship to gender and age using cone beam computed tomography (CBCT).

DESIGN

Cross-sectional SETTING: CBCT images acquired from the maxillofacial radiology department in a dental school.

PATIENT AND METHODS

CBCT scans of 1010 maxillary sinuses from 505 patients were analyzed to determine the prevalence, location, type, and orientation of maxillary sinus septa. Descriptive statistics, chi-square tests and t tests were used to analyze the data.

MAIN OUTCOME MEASURES

The prevalence, location, type, and orientation of maxillary sinus septa.

SAMPLE SIZE

1010 sinuses from 505 patients.

RESULT

Approximately 46% of the studied patients had maxillary septa, which were present in 370 (37%) sinuses. About 64% of the septa were present on the right side and 85.7% of all septa were mediolater-ally oriented. The mean height of the septa was 6.06 mm (0.84) in the right sinuses and 5.70 mm (0.93) in the left sinuses. Multiple septa were found in 101 patients (20%). Among males, 58.5% had septa compared to 34% of females (P<.001.) A significant positive association was found between age and the presence and number of septa, P<.001.

CONCLUSIONS

Maxillary sinus septa were highly prevalent with various heights and directions among the studied sample. Careful assessment of different anatomic variation must be conducted prior to any maxillary sinus augmentation, particularly in older patients.

LIMITATIONS

Cross-sectional evaluation of CBCT images from one dental school patient population; thus, the findings cannot be generalized to other populations.

CONFLICT OF INTEREST

None.

Three-Dimensional Evaluation of Maxillary Sinus Changes in Growing Subjects: A Retrospective Cross-Sectional Study

This study aims to evaluate changes of maxillary sinuses in growing subjects. Cone Beam Computed Tomography (CBCT) scans of 146 patients were divided according to gender and age (6–8, 9–11, 12–14 years old). Left, right and total maxillary sinus volume (MSV-R, MSV-L, MSV-Tot) and surface (MSS-R, MSS-L, MSS-Tot), left and right linear maximum width (LMW-L, LMW-R), depth (LMD-R, LMD-L) and height (LMH-R, LMH-R) were calculated using Mimics Research 22. Kruskal–Wallis Test and showed a statistically significant increase in both genders for all variables. Pairwise comparisons in females are always statistically significant in: LMH-R, LMH-R, MSS-Tot, MSV-Tot. All other variables showed a statistical significant increase between 9–11 and 12–14, and between 6–8 and 12–14 age groups, apart from LMSW-R, LMSW-L, LMSD-R, LMSD-L between 6–8 and 12–14 age groups. Pairwise comparisons in males are always and only statistically significant between 9–11 and 12–14, and between 6–8 and 12–14 groups. Symmetrical measurements (right and left) evaluated using Wilcoxon test retrieved no statistical significant difference. Comparisons between measurements on male and female subjects using Mann–Whitney test showed a statistical significant difference in 6–8 years group in MSV-R, MSV-L and MSV-Tot, and in 12–14 age group in MSV-R, MSV-L, MSV-Tot, MSS-r, MSS-l, MSS-Tot, MSW-R, MSW-L, MSD-R, MSD-L. Intraclass Correlation Coefficient (ICC) assessing inter-operator and intra-operator concordance retrieved excellent results for all variables. It appears that maxillary sinus growth resembles the differential peak of growth in male and female subjects. Sinuses starts to develop early in female subjects. However, in the first and last age group female sinuses are statistically significantly smaller compared to male ones. In male subjects, sinus growth occurs mainly between the second and third age group whilst in female subjects it starts between the first and second age group and continues between the second and the last. Sinus has a vertical development during the peak of growth, which is the main reason for its increase in volume.

Treatment of Class II malocclusion with tooth movement through the maxillary sinus

This case report describes the successful extraction treatment of a Class II malocclusion with excessive maxillary sinus pneumatization. A 20-year-old man sought treatment with the major complaint of protrusive mouth and anterior teeth. He was diagnosed with a skeletal Class II relationship and protrusion of the maxilla. The clinical examination showed a severe Class II molar relationship with excessive overjet and deep overbite. Panoramic radiograph showed obvious maxillary sinus pneumatization bilaterally. Three premolars and one deciduous molar were extracted, and spaces were used to correct molar relationship and retract maxillary incisors. Light forces and low speed movement were applied to overcome the challenge of moving teeth through the maxillary sinus wall. Balanced facial esthetic and stable occlusion were obtained posttreatment with a notable bone formation of the maxillary sinus wall. This result highlights the possibility of tooth movement through cortical floor with bone remodeling and no obvious complications.

Maxillary sinus size and posterior tooth inclination in Japanese orthodontic patients with agenesis of maxillary second premolars

The purpose of this study was to investigate the expansion of the maxillary sinus and the inclinations of posterior teeth in orthodontic patients with maxillary second premolar agenesis. A total of 30 subjects with one or two congenitally missing maxillary second premolars and retained maxillary deciduous second molars (a agenesis group) were selected and divided into a unilateral agenesis group (20 subjects with one maxillary second premolar missing) and a bilateral agenesis group (10 subjects with two maxillary second premolars missing). As controls, 30 sex- and age-matched subjects without agenesis of the maxillary second premolars were selected. Oblique cephalograms were used to investigate the association of maxillary second premolar agenesis and lower maxillary sinus size and posterior tooth inclinations. Agenesis of the maxillary second premolars induced significantly large lower maxillary sinus length, depth, area and mesial inclination of the maxillary first premolar, a significantly small anterior maxillary length, and a significantly more distal position for root apex of the maxillary first premolar. There were no significant differences in any measurements of the lower maxillary sinus and posterior teeth between the non-agenesis side in the unilateral agenesis group and the control group. Maxillary second premolar agenesis caused inferior and anterior expansion of the lower maxillary sinus and the mesial inclination of the maxillary first premolars with a distal position of root apex. Unilateral agenesis of the maxillary second premolar did not affect on the lower maxillary sinus size or posterior tooth inclinations of the unaffected antimere.

Envisioning Post-treatment Occlusions after Space Closure Using Temporary Skeletal Anchorage Devices

Missing posterior teeth and posterior tooth extractions are commonly seen and needed within orthodontic practices. With the invention of temporary skeletal anchorage devices (TSADs), clinicians can now effectively close posterior tooth spaces. Various molar occlusions are discussed to help clinicians envision post-treatment occlusions after posterior teeth space closure using TSADs.

Proximity of the roots of posterior teeth to the maxillary sinus in different facial biotypes

INTRODUCTION

Orthodontists consider facial growth pattern and oral function when developing a treatment plan. Less attention is given to the relationship between the maxillary posterior teeth and the maxillary sinus. We aimed to evaluate the relationship between the roots of the maxillary posterior teeth and the floor of the maxillary sinus.

METHODS

Proximity of the roots to the maxillary sinus was scored for the left and right first and second premolars and molars (scores, 0-3). Mean scores per patient and per tooth type were calculated. The influences of age, sex, and facial biotype on mean scores per patient and tooth were analyzed.

RESULTS

The mean scores per patient and the second molar scores were significantly lower in the normodivergent subjects compared with the hypodivergent subjects, and in the hypodivergent vs the hyperdivergent groups, indicating that the hypodivergent biotype had significantly fewer second molar roots into the sinus than the normodivergent and hyperdivergent biotypes. Age had no effect on mean score per patient, but in the hyperdivergent group, the second molar score increased with age, meaning that second molar roots tend to be closer to the sinus floor.

CONCLUSIONS

In a young population (7-24 years), the positions of the apices of the maxillary second molar roots in relation to the maxillary sinus floor are associated with the facial biotype. In a hypodivergent biotype, the roots of the second molars are located farther from the sinus floor compared with the normodivergent and hyperdivergent facial patterns.

Knowledge of orthodontic tooth movement through the maxillary sinus: a systematic review

Background

To investigate the feasibility, safety and stability of current interventions for moving teeth through the maxillary sinus (MTTMS) by performing a systematic review of the literature.

Methods

The electronic databases PubMed, Embase, CENTRAL, Web of Science, CBM, CNKI and SIGLE were searched without a language restriction. The primary outcomes were parameters related to orthodontic treatment, including orthodontic protocols, magnitude of forces, type of tooth movement, duration and rate of tooth movement, and remolding of alveolar bone and the maxillary sinus floor. The secondary outcomes were safety and stability, including root resorption, perforation of the sinus floor, loss of pulp vitality and periodontal health and relapse.

Results

Nine case reports with 25 teeth were included and systematically analyzed. Fifty to two hundred g of force was applied to move teeth through the maxillary sinus. Bodily movement was accomplished, but initial tipping was observed in 7 cases. The rate was 0.6–0.7 mm/month for molar intrusion and 0.16–1.17 and 0.05–0.16 mm/month for mesial-distal movement of premolars and molars, respectively. Bone formation and remolding of the sinus floor occurred in 7 cases. Root resorption within 6 to 30 months was observed in 3 cases, while no cases of perforation of the sinus floor, loss of pulp vitality, periodontal health impairment or relapse were reported.

Conclusions

At the present stage, no evidence-based protocol could be recommended to guide MTTMS. The empirical application of constant and light to moderate forces (by TAD, segment and multibrackets) to slowly move teeth through or into the maxillary sinus in adults appears to be practical and secure. Bodily movement was accomplished, but teeth appear to be easily tipped initially, potentially resulting in root resorption. However, this conclusion should be interpreted with caution as the currently available evidence is based on only a few case reports or case series and longitudinal or controlled studies are lacking in this area.

Mesiodistal dental movement toward remodeled edentulous alveolar ridge: Digital model assessment

INTRODUCTION

The aims of this study were to compare the changes in posterior dental inclination and angulation, and the posterior tooth crown sizes and alveolar ridge thicknesses consequent to the orthodontic procedures of closing and opening of mandibular first molar edentulous spaces.

METHODS

The sample comprised 16 patients (4 men, 12 women) with an initial mean age of 34.17 years and unilateral or bilateral absence of mandibular permanent first molars. The space closure group (SCG) comprised 12 hemiarches with a mandibular first molar edentulous space varying from 2 to 7 mm, orthodontically treated with space closure. The space opening group (SOG) comprised 14 quadrants with a mandibular first molar edentulous space varying from 7.1 to 12 mm, orthodontically treated with space reopening for prosthetic replacement. Digital dental models were obtained before treatment and after space closure or opening, and posterior tooth angulation and inclination, cervico-occlusal crown height, and alveolar ridge thickness were evaluated. Interphase and intergroup comparisons were performed with dependent t tests and t tests, respectively (P <0.05).

RESULTS

Mandibular second molar uprighting and changes in buccolingual inclination of the posterior teeth were similar in the groups. The second molar cervico-occlusal crown height increased in the SCG and decreased in the SOG. The alveolar ridge thickness increased in the SCG and remained stable in the SOG.

CONCLUSIONS

The only significant intergroup differences were that the second molar cervico-occlusal crown height and the alveolar ridge thickness increased in the SCG, and decreased and remained stable in the SOG.

Retrospective study of maxillary sinus dimensions and pneumatization in adult patients with an anterior open bite

INTRODUCTION

The aim of this study was to evaluate differences in the maxillary sinus floor levels between adults with an anterior open bite and those without.

METHODS

This retrospective study included 30 subjects: 15 adults with an anterior open bite (mean age, 21.5 ± 4.3 years) and 15 control subjects with normal occlusion (mean age, 21.7 ± 3.1 years). Cone-beam computed tomography and lateral cephalograms were analyzed before treatment.

RESULTS

The open-bite group exhibited a significantly greater maxillary posterior alveolar height (P <0.05). The craniocaudal heights of the maxillary sinus in the region between the first and second molars and between the second premolar and first molar were significantly greater in the open bite group (40.5 and 39.0 mm, respectively) than in the control group (36.7 and 34.7 mm, respectively; P <0.05 for both). The basal bone heights in the regions between the first and second molars, the second premolar and first molar, and the first and second premolars were significantly smaller in the open-bite group than in the control group (P <0.001 for all).

CONCLUSIONS

Vertical pneumatization of the maxillary sinus floor in the region between the first and second molars and between the second premolar and first molar is greater in adults with an anterior open bite than in those without, whereas basal bone height in the maxillary posterior region is lower in the open-bite patients.

Miniplate With a Bendable C-Tube Head Allows the Clinician to Alter Biomechanical Advantage in Extremely Complicated Anatomic Structure

BACKGROUNDS

This article reports C-tube miniplates as a practical temporary anchorage device choice to treat open bite patients with maxillary sinus pneumatization.

METHODS

The C-tube components are titanium anchor plates and monocortical screws that are basically similar to any other miniplate systems, but it has the unique characteristic of the tube head to be malleable. The manipulation of the head part is easy due to the composition of pure titanium. The I-shaped C-tube with 3 holes and T-shaped C-tube miniplates were placed above the apices of maxillary molars as an absolute anchorage system to intrude the posterior maxilla. The bending of the tube heads assisted in reduction of severe open bite patient with maxillary sinus pneumatization.

RESULTS

Sinus perforation during placement of skeletal anchorage system weakens stability of the anchorage and further cause complications. Placement of titanium C-tube miniplates allowed reliable skeletal anchorage and avoided maxillary sinus perforation in patients with extreme pneumatizations. Simple bending of C-tube miniplates ensured increased orthodontic intrusion force without having to replace them, and eliminated consequences such as perforation of maxillary sinus, sinusitis, soft tissue irritation, or infection.

CONCLUSIONS

Anatomic difficulties in the placement of temporary anchorage device can be easily managed by using the bendable C-tube miniplate. It can serve as a great alternative over miniscrews or regular miniplates with reduced risk of sinus perforation and ability to bend the head portion to control orthodontic vectors and forces.

[The search for excellence in adult orthodontics; an interview with Bjørn U. Zachrisson]

Bjørn U. Zachrisson est Professeur Émérite au sein du Département d’Orthodontie de l’Université d’Oslo (Norvège). Il conserve à Oslo une pratique libérale consacrée aux traitements de l’adulte.

Il a rédigé plus de 270 articles cliniques et scientifiques, publiés dans des revues internationales et dans des manuels d’orthodontie, de parodontologie, de traumatologie et de dentisterie générale.

Il a représenté l’orthodontie européenne à l’occasion de multiples congrès à travers le monde. Il a présenté de nombreuses conférences magistrales et donné des cours pendant les congrès internationaux.

Bjørn U. Zachrisson a reçu toutes les récompenses essentielles en orthodontie, y compris le prix Ketcham et Jaraback décerné par l’American Association of Orthodontics. Il est co-rédacteur du Journal of Clinical Orthodontics, rédacteur et auteur de «Ask an Expert» dans le World Journal of Orthodontics. Il collabore à l’Editorial Board of the Seminars in Orthodontics, à l’Angle Orthodontist, au World Journal of Orthodontics, à la Revista Dental Press de Ortodontia e Ortopedia and Revista Clinica de Ortodontia (Brésil), à l’Italian Journal of Orthodontics, ainsi qu’à l’European Journal of Esthetic Dentistry.