|Year : 2020 | Volume
| Issue : 1 | Page : 49-54
Influence of age and gender in the assessment of inter-radicular and cortical bone thickness of the anterior maxilla and mandible for the placement of orthodontic mini-implants by cone-beam computed tomography: A retrospective study
Pragati Bramhe, Ajay Bhoosreddy, Chetan Bhadage, Prutha Rathod, Prajakta Chaudhari, Dipika Utekar
Department of Oral Medicine and Radiology, MGV'S K. B. H. Dental College and Hospital, Nashik, Maharashtra, India
|Date of Submission||17-Dec-2019|
|Date of Decision||23-Jan-2020|
|Date of Acceptance||30-Jan-2020|
|Date of Web Publication||29-Jul-2020|
Flat No. 207, Honey Archana Complex B-2 Wing, Untakhana, Medical Road, Nagpur - 440 009, Maharashtra
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aim: To evaluate the cortical bone thickness in the anterior maxilla and mandible for the placement of orthodontic mini-implant in different age and gender using cone-beam computed tomography (CBCT). Objectives: To determine whether the studied anatomic measurements vary with age and gender of the patients and to determine the optimal sites for mini-implant placement by measuring inter-radicular and cortical bone thickness in the anterior maxilla and mandible. Materials and Methods: CBCT images of 120 (60 males and 60 females) patients were divided into three age groups (15–20, 21–30, and 31–40 years). Measurements were done for each inter-radicular space in the anterior maxilla and mandible at four different depths, i.e., at a distance from cementoenamel junction (CEJ) up to 3, 5, 7, and 9 mm apical to CEJ. The mesiodistal (MD), buccolingual (BL), Palartal cortical (PC), Lingual Cortical (LC) bone thickness was measured. Results: The mean measurement of MD, BL and buccal cortical (BC), and PC/LC cortical bone thickness on both sides of the maxilla at 9 mm is highest at distal to 13 and 23; in the mandible, it is highest between 42 and 43, 32 and 33. BL width at 3, 5, 7, and 9 mm is significantly highest in the maxilla in males. In mandible BL, width at 3 mm was significantly highest in males. PC thickness at 3mm (1.856±0.789) and BC (1.214 ±0.224 ), PC (2.226 ±2.114) thickness at 9mm bone level in maxilla was significantly highest at 31-40 years. Conclusion: There is an influence of age and gender on inter-radicular and cortical bone thickness of the anterior maxilla and mandible for the placement of orthodontic mini-implants.
Keywords: Cone-beam computed tomography, cortical bone, mini-implants, optimal site
|How to cite this article:|
Bramhe P, Bhoosreddy A, Bhadage C, Rathod P, Chaudhari P, Utekar D. Influence of age and gender in the assessment of inter-radicular and cortical bone thickness of the anterior maxilla and mandible for the placement of orthodontic mini-implants by cone-beam computed tomography: A retrospective study. J Int Clin Dent Res Organ 2020;12:49-54
|How to cite this URL:|
Bramhe P, Bhoosreddy A, Bhadage C, Rathod P, Chaudhari P, Utekar D. Influence of age and gender in the assessment of inter-radicular and cortical bone thickness of the anterior maxilla and mandible for the placement of orthodontic mini-implants by cone-beam computed tomography: A retrospective study. J Int Clin Dent Res Organ [serial online] 2020 [cited 2020 Aug 5];12:49-54. Available from: http://www.jicdro.org/text.asp?2020/12/1/49/291118
| Introduction|| |
Cone-beam computed tomography (CBCT), a three-dimensional imaging modality, permits the dental professional to visualize what the conventional radiographs never showed, the thickness and level of labial/buccal and lingual alveolar bone. Previously to the introduction of CBCT, the visualization of labial, buccal, and lingual cortical (LC) bone was not possible due to image superimposition of conventional radiographs and due to gingival covering in clinical analysis.
Recently, mini-implants have been extensively used as a reliable source of anchorage in orthodontics. Their small size, which allowed placement in inter-radicular areas; easy placement and removal; excellent anchorage; and low cost are main advantages.,
Mini-implants have become a very popular type of orthodontic skeletal anchorage, which is reflected in the escalating number of studies addressing this subject. However, there is still no consensus in these studies about the factors that influence the success of mini-implants. A recent systematic review could not prove an association between the type of mini-implant, patient characteristics, placement site, surgical technique, and orthodontic and implant maintenance factors and the success rates of mini-implants.
Anchorage is the most important factor that affects the treatment plan and the orthodontic treatment result. Recently, different kinds of skeletal anchorage have attracted the attention of orthodontists. Miniscrews originally used for bone fixation have been used widely as auxiliary anchorage devices for tooth movement without a great compliance requirement for orthodontic patients.,
The most common implant sites appear to be the palate, the palatal aspect of the maxillary alveolar process, the retromolar area in the mandible, and the buccal cortical (BC) plate in both the maxilla and the mandible. Among the important factors that should be considered when choosing mini-implant placement sites are soft-tissue anatomy, inter-radicular distance, sinus morphology, nerve location, buccolingual (BL) bone depth, and buccal and LC thicknesses.
Several studies provide measurements of the inter-radicular spaces at the posterior maxilla and mandible. It was reported that the volume of bone in the maxillary inter-radicular space between the second premolar and the first molar provides the optimal anatomic site for miniscrews in the maxilla., It ws reported from previous studies; inter-radicular spaces in the posterior maxilla between 1st and 2nd premolar; 2-8mm from the alveolar crest. For posterior mandible it was between the first and second molar.
Limited data are available concerning the inter-radicular spaces of the anterior maxillary and mandibular areas in spite of the fact that mini-implants can also be useful in the anterior region as anchorage for mesial movement of the posterior dentition or correction of the anterior vertical occlusion.,, The influence of age and gender in success of mini-implants remains controversial. It seems that cortical bone is thinner in females mesial to the maxillary first molar.
Thus, the present study aims to evaluate the optimal sites of mini-implant in the anterior maxillary and mandibular region.
| Materials and Methods|| |
This present retrospective study was carried out at the Department of Oral Medicine and Radiology, MGV's K. B. H Dental College and Hospital, Nasik, after obtaining approval from the Institutional Ethical Committee.
Scans of the patients from the database were selected with the age group of 15–20 years, 21–30 years, and 31–40 years.
- Overlapping of crowns or roots of adjacent teeth
- Missing teeth
- Periodontal diseases
- Blurred or unclear images
- Severe ectopic eruptions.
A total of 120 CBCT scans were selected (60 females and 60 males) in whom there were 66 maxilla and 54 mandibles. The scans were divided into three age groups: 15–20 years (25 males and 22 females), 21–30 years (25 males and 18 females), and 31–40 years (15 males and 20 females). Forty scans in each group were selected.
Measurements were done for each inter-radicular space in the anterior maxilla and anterior mandible from distal to canine of the one side to distal to canine of the other side, i.e., between 11 & 12, 12 & 13, distal to 13, 11 & 21, 21 & 22, 22 & 23, distal to 23 in maxilla and in mandible between 31 & 32, 32 & 33, distal to 33, 31 & 41, 4 & 42, distal to 43.
The MD, BL and BC and PC thickness was measured in the maxilla. Similarly, the MD, BL and BC and LC thickness was measured in mandible at four different from cementoenamel junction(CEJ) upto 3 mm, 5 mm, 7 mm, 9 mm [Figure 1]. Scans were taken in CBCT machine (OrthoPhos XG3D, DentsPly Sirona) with FOV 8 × 8".
|Figure 1: (a) inter-radicular distance from cementoenamel junction up to 3 mm. (b) Inter-radicular distance from cementoenamel junction up to 5 mm. (c) Inter-radicular distance from cementoenamel junction up to 7 mm. (d) Inter-radicular distance from cementoenamel junction up to 9 mm|
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The MD thickness was measured at the widest distance between each two adjacent teeth [Figure 2].
|Figure 2: dimensions; bucclingual (bl), mesiodistal (md), buccal cortical(bc) and lingual cortical (LC) & palatal cortical (PC) bone thickness|
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The BL thickness was measured from the outermost point on buccal side to the outermost point on lingual and palatal side at the middle of distance between each two adjacent teeth [Figure 2].
Cortical bone thickness
Buccal and PC thickness was measured from the outermost point on buccal/palatal side to the inner point of BC/PC side in the middle of inter-radicular distance between each two adjacent teeth [Figure 2].
Being an observational noncomparative study, the distribution of means of inter-radicular and cortical bone thickness measurements has not been compared statistically across different cut levels as well as different sites included in the study. However, descriptive statistical measures were used to obtain the mean and standard deviation (SD) of all the studied measurements. With reference to the objectives of comparing the measurement across various age groups and gender, statistical analysis was performed using Student's t-test and ANOVA test. P < 0.05 was considered statistically significant.
| Results|| |
[Table 1] shows the mean and SD of measurements of BL width (11.43 ± 1.53), MD width (2.28 ± 0.76), BC thickness (1.94 ± 0.76), and PC thickness (4.19 ± 1.65) of the right side of the anterior maxilla, which is highest at distal to 13 regions at 9 mm bone level.
[Table 2] shows the mean and SD of measurements of BL width (11.51 ± 1.35), MD width (2.30 ± 0.24), BC thickness (1.97 ± 0.43), and PC thickness (4.23 ± 1.25) of the left side of the anterior maxilla, which is highest at distal to 23 region at 9 mm bone level.
[Table 3] shows the mean and SD of measurements of BL width (9.63 ± 0.41), MD width (2.58 ± 0.32), BC thickness (1.40 ± 0.20), and LC thickness (2.79 ± 0.49) of the left side of the anterior mandible, which is highest at inter-radicular space between 32 and 33 and 9 mm bone level.
[Table 4] shows the mean and SD of measurements of BL width (9.61 ± 0.69), MD width (2.55 ± 0.23), BC thickness (1.38 ± 0.38), and LC thickness (2.77 ± 0.79) of the right side of the anterior mandible, which is highest at inter-radicular space between 42 and 43 and 9 mm bone level.
[Table 5] shows that on comparing gender-wise measurements in the anterior maxilla, males had significantly higher BL thickness at the 3 mm (9.217 ± 1.009; P: 0.034), 5 mm (9.345 ± 1.641; P: 0.015), 7 mm (9.536 ± 1.450; P: 0.017), and 9 mm (9.793 ± 1.641; P: 0.010) level from the CEJ [Table 5].
|Table 5: Comparisons between measurements of males and females in the anterior maxillary region using Studentfs t-test|
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[Table 6] shows that on comparing gender-wise measurements in the anterior mandible, males had significantly higher BL thickness at 3 mm (7.217 ± 0.090; P: 0.024) level from CEJ.
|Table 6: Comparisons between measurements of males and females in the anterior mandibular region using Student's t-test|
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[Table 7] shows the comparison between mean and SD of measurements of three age groups, i.e., 15–20, 21–30, and 31–40 years in the anterior maxilla and it is found that the age group of 31–40 years shows the highest PC thickness at 3 mm bone level followed by the age group of 21–30 years and also the BC thickness is highest at 31–40 years of age followed by 21–30 years of age at 9 mm bone level and it is statistically significant.
|Table 7: Comparisons between measurements of three age groups in the anterior maxillary region using Student's t-test|
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In contrast, there was no significant difference found between the age groups in the anterior mandible [Table 8].
|Table 8: Comparisons between measurements of three age groups in the anterior mandibular region using Student's t-test|
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| Discussion|| |
Several factors could affect the success rates and effectiveness of mini-implants used for establishing skeletal orthodontic anchorage. Some of these factors are implant related (type, diameter, and length of the implant), patient related (sex, age, and physical status), surgical related (direction of mini-implant placement and placement torque), orthodontic related (magnitude and timing of force), location related (peri-implant bone quantity, cortical bone thickness, and keratinized versus oral mucosa), and implant-maintenance related. The exact role of these factors, however, is not fully understood.
The present study investigated the anatomic data gathered from 120 CBCT images to determine the optimal sites for mini-implant placement by studying two elements that are related to the mini-implant location factor: inter-radicular bone dimensions and cortical bone thickness. Three-dimensional measurements of the inter-radicular spaces at four vertical levels (3 mm, 5 mm, 7 mm, and 9 mm) from the CEJ were performed, and these measurements were also compared with gender and three age groups, i.e., 15–20, 21–30, and 31–40 years.
Miyawaki et al. found no correlation between mini-implant success rate and clinical parameters such as gender and implant location. However, in the present study, it is found that males have significantly higher BC bone thickness than females.
In this study, the CEJ was selected as the starting point for the measurements that used the alveolar crest, which could be affected by different periodontal problems., Lim et al. excluded levels higher than 6 mm in their study on inter-radicular soft tissue for the same reason, but in the present study, we have considered the measurements up to 9 mm to know the optimal sites or safe zone for the placement of mini-implant.
Baumgaertel and Hans observed a thicker BC bone in the mandible. However, in the present study, BC thickness was highest in the anterior maxilla.
In the study by Swasty et al., the age group of 40–49 years had a significantly higher BC thickness in the mandible. In the present study, the age group of 31–40 years had significantly higher BC, and also more significant differences were found between the gender in the maxilla than in the mandible. Thus, it would be accepted that mini-implants placed in males and in those older than 20 years to have higher success rates because of the higher inter-radicular dimensions and thicker cortical bone thickness, especially in the maxilla.
Based on the findings of the present study, the optimal site for the placement of mini-implants in the anterior maxilla is distal to canine region, and in the anterior mandible, the optimal site for the placement of mini-implant is the inter-radicular space between the lateral incisors and canines.
| Conclusion|| |
Males had a significantly higher BL, palatal, and BC thickness as compared to females at specific levels and sites in the maxilla and the mandible.
The age group older than 20 years had higher PC and BC thickness in the anterior maxilla.
The optimal site for the placement of mini-implants in the anterior maxilla is distal to canine region, and in the anterior mandible, it is inter-radicular region between lateral incisor and canine.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]