Anatomical study of the maxillary tuberosity using cone beam computed tomography

Variability in Positions and Factors Contributing to Surgical Difficulty of Impacted Third Molars

OBJECTIVES

 This study aimed to provide valuable insights into the variability of third molar positions and factors influencing their surgical time and technique.

MATERIALS AND METHODS

 This cross-sectional study included a total of 48 eligible participants, aged 18 to 45 years, diagnosed with impacted teeth, and who had undergone surgery. Exclusion criteria comprised the absence of the second molar, the presence of systemic diseases, a history of radiation therapy, and pregnancy or lactation. Participants completed a questionnaire covering demographic data, physical metrics, and information on systemic conditions and disorders. Preoperative assessments included vital sign measurements. Panoramic imaging was employed to evaluate the third molar distance to the occlusal plane, degrees of angulation, eruption space, and distance to the alveolar inferior canal. Surgical difficulty in this study was measured by two outcomes: surgical time and technique.

STATISTICAL ANALYSIS

 To assess differences in impacted third molar positions among groups, Independent samples t-test and One-way analysis of variance were used for normally distributed data without outliers; otherwise, the Mann-Whitney U test and Kruskal-Wallis H test were utilized. The Spearman's rank correlation was utilized to explore relationships between vital signs, impacted third molar positions, surgical time, and surgical technique.

RESULTS

 There were no significant differences in third molar positions between age and body mass index groups. Significant differences in distance to the occlusal plane were observed between third molars in quadrants 2 and 3 (p = 0.002) and quadrants 2 and 4 (p = 0.005). A significant difference in eruption space was found between sexes (p = 0.016). A significant negative correlation was discovered between surgical time and respiration rate per minute (p = 0.028).

CONCLUSION

 This study found that males have greater third molar eruption space than females, and maxillary third molars have a greater distance to the occlusal plane compared with mandibular third molars. The importance of vital signs as contributing factors to surgical difficulty is highlighted, emphasizing their relevance in clinical practice.

Discriminating between the maxillary tuberosity and the alveolar tuberosity- a critical pictorial review

PURPOSE

The maxillary tuberosity, a critical anatomical landmark in dentistry and maxillofacial surgery, is burdened by terminological confusion. This inconsistency hampers clinical practice and communication across disciplines.

METHOD

Different resources were used to argue for the necessity of standardising the terminology related to maxillary tuberosity to enhance diagnostic precision and ultimately improve patient outcomes.

RESULTS

Most clinical and surgical studies dealing with the distal alveolar bone of the maxilla erroneously indicate it as "maxillary tuberosity". By recognising the diverse definitions of this structure, errors and misinterpretation of studies could be reduced, and interdisciplinary collaboration could be improved. The term "alveolar tuberosity" is recommended to refer specifically to the distal end of the alveolar process of the maxilla. Anatomically, the maxillary tuberosity belongs to the body of the maxilla and forms part of the posterior wall of the maxillary sinus; therefore, it should not be located in the alveolar process.

CONCLUSION

Adhering to the Terminologia Anatomica will clarify the critical clinical and surgical landmarks and enhance communication in clinical and academic settings.

Influence of the maxillary third molars and the surrounding cortical plate during maxillary tooth movement with TADS- A CBCT Study

OBJECTIVE

To determine the influence of the presence/absence of third molars and intact/loss of cortical plate of the maxillary tuberosity on the amount of distal movement of the maxillary first permanent molar during distal movement of the maxillary dentition with mini-implants.

MATERIALS AND METHODS

Thirty six maxillary tuberosity sites were evaluated in eighteen young adult patients. The distal movement of the entire maxillary dentition was performed with mini-implants with 200 g of distalising force applied from the mini-implant placed in the maxillary posterior buccal region to attachments placed on the arch wire between the maxillary lateral incisor and canine bilaterally. The distal movement of the maxillary first permanent molars was measured on lateral cephalograms. The maxillary tuberosity sites with intact cortical plate due to congenitally missing third molars or atraumatic extraction of third molars (G1), partial loss of cortical plate due to surgical removal of third molars (G2), fully erupted third molars (G4), third molars located at (G3), and below the cementoenamel junction (G5) were evaluated with cone beam computed tomography. One way Anova and Fisher LSD test was done.

RESULTS

The order of greater to lesser amount of distal movement of the maxillary first permanent molar depending on the integrity of maxillary of tuberosity was partial loss of cortical plate, third molars at the cementoenamel junction, third molars below the cementoenamel junction, intact cortical plate and fully erupted third molars.

CONCLUSION

The integrity of the cortical plate and the relative position of the maxillary third molar to the second molar influence the amount of distal movement of the maxillary first permanent molar during distal movement of the maxillary teeth with TADS.

CLINICAL RELEVANCE

The amount of distal movement of the maxillary dentition appears to depend on the presence or absence of the third molars and the condition of the cortical plate in the region of the maxillary tuberosity and thereby greatly influence the outcome of treatment.

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.

Three-Dimensional Assessment and Comparison of the Maxillary Tuberosity Between Skeletal and Dental Class I and Class II Adults in Maxillary Third Molar Agenesis Using Cone Beam Computed Tomography: A Descriptive Cross-Sectional Human Study

AIM AND OBJECTIVE

The objective of this study was to assess and compare the dimensions (width (W), height (H), and length (L)) of the tuberosity distal to maxillary permanent second molar in individuals with skeletal and dental Class I and Class II malocclusions who had maxillary third molar agenesis.

METHODOLOGY

Cone beam computed tomography (CBCT) was used to measure the left (L) and right (R) anatomical tuberosity dimensions in three dimensions using the WillMaster software (HDX WILL Corporation, Korea). The measurements were compared between Class I (n = 35) and Class II (n = 35) normo-hypodivergent adult subjects. The dimensions were measured at regular 2 mm intervals from the cementoenamel junction (CEJ) and distovestibular root of the maxillary second molar in terms of the width (e.g., W1, W2, and W3), height (e.g., H1, H2, and H3), length (e.g., L1, L2, and L3) to the posterior limit of the tuberosity. Statistical analysis included descriptive statistics, Mann-Whitney U tests, and intraclass correlation coefficient tests.

RESULTS

The width of the tuberosity at LW0, LW1, and LW2 was significantly higher in Class I compared to that in Class II. The right tuberosity in Class II showed significantly higher values in height at all reference points. The right tuberosity at RL0 and RL1 exhibited significantly higher values in the length of the Class II group compared to the Class I group.

CONCLUSIONS

The dimensions of the maxillary tuberosity (width, height, and length) varied between the Class I and Class II groups. Wider maxillary tuberosities were observed in the Class I group, while the Class II group had greater height and length dimensions of the tuberosity.

Applications of maxillary tuberosity block autograft

OBJECTIVE

Autogenous bone grafts are considered the gold standard due to their compatibility and osteogenic potential to induce new bone formation through osteogenesis, osteoinduction, and osteoconduction. The aim of this paper was to describe clinical applications of the maxillary tuberosity block autograft in small and moderate localized defects of the alveolar process around implants and teeth.

CLINICAL CONSIDERATIONS

Maxillary tuberosity is often used as a particulate graft for augmentation of deficient alveolar ridge or maxillary sinus prior to or simultaneously with implant insertion, but not as a bone block graft. The maxillary tuberosity block autograft may also provide a valuable bone source for challenging situations such as immediate implant placement into types II and III extraction sockets, treatment of horizontal and vertical bone defects with simultaneous implantation, reconstruction of circumferential defects around implants, and preservation of alveolar ridge.

CONCLUSIONS

The advantages of the maxillary tuberosity include intraoral corticocancellous autogenous graft with fewer intraoperative difficulties, no need for donor site restoration, less morbidity, and an excellent correction of localized alveolar ridge defects.

CLINICAL SIGNIFICANCE

Within the limitations of the presented case reports, the use of maxillary tuberosity block autograft has shown to be successful in alveolar ridges augmentation that lack both width and height.

Anatomical limitations and factors influencing molar distalization

OBJECTIVES

To analyze the anatomical limitations and characteristics of maxillary and mandibular retromolar regions affecting molar distalization using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

A total of 120 qualifying patients were classified into equal groups of skeletal Class II and Class III and stratified by vertical growth pattern, age, sex, and third molar presence. The available distance along the axis of distalization and cortical bone thickness (CBT) were measured in the maxillary and mandibular retromolar regions of Class II and Class III patients, respectively. One-way analysis of variance was used to examine the effects of the factors on the measured data.

RESULTS

The minimum available distance of the Class II maxilla was observed at a level 3 mm from the cementoenamel junction (CEJ), while that of the Class III mandible was at a level 9 mm from the CEJ. The average available distance at the limit level was 4.06 ± 1.93 mm in the Class II maxilla, and the average corresponding CBT was 1.00 mm. The average available distance at the limit level in the Class III mandible was 2.80 ± 1.96 mm, and the corresponding CBT was 2.24 mm. In both skeletal Class II and Class III patients, hyperdivergent groups had the least available distance for molar distalization.

CONCLUSIONS

The limit for available distance in the Class II maxilla is closer to the coronal level, while that of the Class III mandible is closer to the apical level. A hyperdivergent growth pattern in a patient is indicative of less potential for molar distalization. Axial slices of CBCT images provide valuable evaluation for molar distalization regarding limit levels.

Total maxillary arch distalization with modified C-palatal plates in adolescents: A long-term study using cone-beam computed tomography

INTRODUCTION

The aims of this study were to evaluate the long-term skeletodental effects, the volume of maxillary tuberosity, and airway space changes after maxillary molar distalization using modified C-palatal plate (MCPP) in adolescents with Class II malocclusion.

METHODS

The sample consisted of 20 adolescent patients (MCPP group; mean age, 12.9 ± 1.0 year) who underwent bilateral distalization of their maxillary dentition and 20 subjects as a control group. In the MCPP group, cone-beam computed tomography images were taken before distalization, at the end of the treatment, and during retention with a minimum of a 3-year posttreatment follow up period. Repeated measures ANOVA followed by post-hoc analysis with the Bonferroni test were used to identify significant differences between time points.

RESULTS

After the long-term observation period, sagittal skeletal and dental relationships were maintained (there were no significant changes in ANB, occlusal plane angle, and overjet postretention). The vertical skeletal dimension did not change during treatment and was stable at the long-term follow-up (the mandibular plane angle and ANS-Me were relatively well maintained). The volume of the maxillary tuberosity showed no significant change during long-term retention. However, the volume was significantly smaller in the treatment group than in the control group (P <0.0001). There were no significant airway space changes after distalization and the postretention period. In addition, there was no significant difference between the MCPP and control groups.

CONCLUSIONS

Improved sagittal skeletal and dental relationships because of treatment were maintained in the long-term evaluation. There was no negative long-term effect on airway space associated with the maxillary arch distalization. Therefore, these findings might be beneficial for clinicians in diagnosis and treatment planning for Class II malocclusion in adolescents.

Miniscrew mechanics for molar distalization and incisor intrusion in a patient with a Class II brachyfacial pattern and gummy smile

A gummy smile is one of the most problematic characteristics in patients with a Class II Division 2 malocclusion, and the correction of vertical position and incisor torque is often challenging for the orthodontist. This case report describes the orthodontic treatment of a 31-year-old woman, assisted by miniscrew mechanics for maxillary arch distalization and correction of a gummy smile with a brachyfacial pattern. Two different mechanics were used. Miniscrews were placed in both maxillary tuberosities, and the maxillary arch was successfully distalized, correcting the Class II relationship. Interradicular miniscrews were placed for maxillary and mandibular incisor intrusion to correct the gummy smile, overbite, and torque. Finally, periodontal surgery was performed to lengthen the maxillary incisor crowns. Satisfactory smile esthetics and good occlusion were achieved. Follow-up after 24 months confirmed that the outcome was stable.

Which one closes extraction spaces faster: en masse retraction or two-step retraction? A randomized prospective clinical trial

OBJECTIVES

To compare the time to close extraction spaces between en masse (ER) and two-step retraction (TSR).

MATERIALS AND METHODS

Forty-eight patients with bimaxillary protrusion underwent treatment with extraction of four first premolars. All patients were randomly allocated to one of two groups: ER (n = 24) or TSR (n = 24). The main outcome was the time required to close spaces between ER and TSR; the closing time of spaces between females and males was a secondary outcome. The size of premolars was measured on the models and data were collected on clinical records at the following times: retraction start date (T1) and space closure completion date (T2). The total time to close the extraction spaces was calculated for each extracted premolar (T1 to T2). The Kaplan Meier method and the Log-Rank test were used to compare the groups.

RESULTS

The time to close extraction spaces showed significant differences between the ER and TSR groups. While ER took between 12.1 and 13.8 months, TSR took between 24.7 and 26.8 months. The TSR group showed a significant difference between sexes; male patients took 5.5 months longer than female patients for the extraction spaces to close.

CONCLUSIONS

TSR takes between 1.8 and 2.2 times longer than ER to close the extraction spaces and it took longer in males than females.