|Year : 2019 | Volume
| Issue : 3 | Page : 125-129
Orthodontic perspective in causing the severity of malocclusion in hypodontia patients: A clinical study
Deepankar Bhatnagar1, Tahira Bawa1, Rupinder Matharoo2, Dipti Bhatnagar3, Deepika Jhangu4
1 Department of Orthodontics and Dentofacial Orthopaedics, Rayat Bahra Dental College and Hospital, Mohali, Punjab, India
2 Department of Oral Medicine and Radiology, MNdav Dental College and Hospitals, Solan, Himachal Pradesh, India
3 Department of Orthodontics and Dentofacial Orthopaedics, Yamuna Institute of Dental Sciences and Research, Gadholi, Yamuna Nagar, Haryana, India
4 Department of Orthodontics, Yamuna Institute of Dental Sciences and Research, Gadholi, Yamuna Nagar, Haryana, India
|Date of Web Publication||3-Jul-2019|
H No. 3512, Sector 38-D, Sector 38, Chandigarh - 160 014
Source of Support: None, Conflict of Interest: None
Aim: This study was aimed to compare Bolton's ratio and the arch width of patients with hypodontia with that of the control group. Materials and Methods: Ten cases with congenitally missing teeth and 10 cases of the control group were grouped in this study. It was guided by Bolton's ratio and Ashley Howe's analysis considering the tooth material and comparing tooth material to jaw size in the latter. Tooth width measurements were compared using a t-test, statistically significant at P < 0.05. Results: Patients with hypodontia shows significantly lower Bolton's ratio as compared to the control group. However, the values when compared statistically were not significant (P > 0.05). Arch width analysis showed significantly reduced basal arch width dimensions in hypodontia patients (P < 0.05) with preponderance toward nonextraction. Conclusion: These findings suggest that the hypodontia patients have comparatively narrower mesiodistal tooth measurements (prominently in posterior segments), lower Bolton's ratio, and reduced basal arch width as compared to control population. The treatment of patients showed preponderance toward nonextraction methodology.
Keywords: Ashley-Howe's analysis, Bolton's ratio, hypodontia, malocclusion
|How to cite this article:|
Bhatnagar D, Bawa T, Matharoo R, Bhatnagar D, Jhangu D. Orthodontic perspective in causing the severity of malocclusion in hypodontia patients: A clinical study. Indian J Dent Sci 2019;11:125-9
|How to cite this URL:|
Bhatnagar D, Bawa T, Matharoo R, Bhatnagar D, Jhangu D. Orthodontic perspective in causing the severity of malocclusion in hypodontia patients: A clinical study. Indian J Dent Sci [serial online] 2019 [cited 2019 Nov 14];11:125-9. Available from: http://www.ijds.in/text.asp?2019/11/3/125/261949
| Introduction|| |
The term hypodontia implies the congenital absence of only a few teeth. When the number of missing teeth exceeds six, it is termed as oligodontia and in case of the complete absence of teeth, it is referred to as anodontia, is the extreme form.,,
Tooth agenesis arises during initial stages of tooth formation (during initiation and proliferation) when the tooth germ fails to develop or/and absent.,, Hypodontia most frequently presents as an isolated developmental disturbance of teeth, but sometimes, it is also associated with certain conditions such as the delayed eruption of permanent teeth due to retained deciduous teeth, taurodontism, peg-shaped maxillary lateral incisors, and ectopic presence of maxillary canine.,,
The etiological factors responsible for tooth agenesis are both environmental and genetic in origin. The environmental factors involve trauma, harmful radiations from chemotherapy, and the genetic factors includes mutations in certain genes or inherited.
The prevalence varies according to the individual characteristics such as the gender, race, and diversity of a person., Hypodontia prevalence is seen more in females as compared to that of males and comparable in both maxilla and mandible. A retrospective study done in India included 673 subjects, found the prevalence of tooth agenesis (16.3%) to be higher than that of other anomalies. Another study reveals the prevalence of hypodontia in school children of the Indian population to be 0.32%.
Hypodontia not only affects the esthetics but also functional abilities such as speech., The decrease in tooth measurements in the anterior regions can lead to retrognathic maxillary arch and prognathic mandibular arch, low mandibular angle, and change in the length of maxilla and mandible which is important for an orthodontist to keep in mind while fabricating an ideal treatment protocol to achieve ideal occlusal and functional balance and esthetic harmony.,
The aim of this study is to calculate and compare Bolton's ratio and the arch width of patients with hypodontia and the control group.
| Materials and Methods|| |
A sample consisting record of 20 patients was evaluated and divided into two groups. Group A (n = 10) with a mean age 16.75 ± 4.25 consisting of study models of patients with hypodontia (with congenitally missing one or more teeth). Group B (n = 10) with a mean age of 18.4 ± 2.29 consisting of patients with ideal/normal occlusion with full complement of teeth. The number of teeth and the presence or absence of missing teeth was confirmed by obtaining orthopantomographs for each patient.
The inclusion criteria for both the groups includes fully erupted all permanent dentition with the exclusion of 3rd molars, availability of dental casts and pretreatment orthopantomographs. The patients with any form of congenital or developmental syndromes, caries and ectopic erupted tooth were excluded from the study.
The study models of 20 patients were evaluated for individual mesiodistal widths using digital Vernier caliper-Mitutoyo [Figure 1]. The mesiodistal diameter of individual tooth for both the groups was calculated on the casts. The maximum distance between the contact points on the two proximal surfaces was measured with accuracy of 0.01 mm using a digital caliper.
All measurements were calculated by one investigator and the given data were subjected first to Bolton's analysis to determine the optimum inter-arch relationship by calculating the overall ratio (ideal-91.3%) and anterior ratio (ideal-77.2%) and to determine whether the discrepancy lies in the mandibular or maxillary teeth in millimeters [Table 1] and [Table 2]. Second, Ashley-Howe's analysis was performed to determine whether hypodontia had an effect on the arch width for which the premolar diameter and premolar basal arch width was calculated and inter-molar and inter-canine widths were also calculated additionally [Table 3] and [Table 4]. Two-sample t-test was used to find the statistical variables between the two groups. The statistical significance level was determined at P < 0.05.
Intra-operator reliability was evaluated on five random study casts from each group and variables were measured again at 1-month interval.
| Results|| |
On comparing Bolton's ratio in both Groups A and B showed difference in anterior and the overall tooth material excess ratio. Patients with hypodontia show significantly lower Bolton's ratio as compared to the control group. However, the values when compared statistically were not significant (P > 0.05).
On subjecting the sample to Ashley-Howe Analysis, indicated that Group A (patients with hypodontia) had significantly smaller basal arch width percentage (premolar basal ach width [PMBAW] %) when compared to control group with P < 0.05.
The inter-canine and inter-molar widths were reduced in Group A when compared to that of Group B. However, the values when compared statistically were not significant (P > 0.05). Similarly, the inter-molar and inter-canine widths were reduced in hypodontia patients, whereas these findings were not statistically significant.
| Discussion|| |
The treatment of anodontia or severe hypodontia is complex and by early detection of missing teeth, alternative treatment modalities can be planned and performed with a multidisciplinary team approach. Hence, the present study was carried out to analyze the effect of one or missing teeth on the extent of malocclusion in hypodontia patients.
For this study, models of patients with hypodontia were obtained and mesiodistal dimensions for individual teeth were calculated. The values were subjected to Bolton's ratio analysis, Ashley-Howe analysis and inter-molar and inter-canine widths were calculated, which are routinely done model analysis during treatment planning in orthodontics to assess the need for expansions or extractions in patients and to find out the extent of discrepancy when compared to a control population comprising individuals with full complement permanent dentition.
Patients with missing one or two permanent teeth showed narrower mesiodistal width of individual tooth when compared to the control group. These findings were in agreement with those of previous studies,,,,,,,, hence indicating an association between hypodontia and smaller tooth size in the remaining dentition. However, Wisth et al. did not find any statistical difference in mesiodistal diameter of the teeth between the hypodontia group and control group with full complement of teeth. Furthermore, Chung et al. found that hypodontia is not associated with reduced tooth size.
Several authors have also assessed the craniofacial morphology of patients with hypodontia. Ben-Bassat et al. (AJODO 2003) concluded that patients with multiple congenitally missing teeth demonstrate a characteristic skeleton-dental pattern, especially those with missing incisors. Karmani et al. (ajodo2002) concluded that patients which showed tooth agenesis had significantly reduced the maxillary size and to a small extent reduced mandibular size. However, these above-mentioned studies evaluated the hypodontia patients craniofacially through two-dimensional cephalometric radiographs. The present study instead used study models to evaluate the effect of hypodontia on the dento-alveolar structure of the affected individuals.
Bolton's analysis is important and taken into consideration for diagnosis, specific treatment planning to achieve proper occlusion with an optimal overjet and overbite. In the present study, Groups A and B showed a difference in anterior and the overall tooth material excess ratio. However, the values when compared statistically were not significant (P > 0.05) which is in concrescence with a study by Han et al. who investigated that the application of Bolton's ratio is important for the proper diagnosis and treatment planning for the Chinese patients with missing mandibular incisors and concluded that it is clinically beneficial for optimal treatment outcomes. However, Smith  evaluated the inter-arch relationships and tooth sizes in three different populations, and the results showed differences based on ethnicity and gender. Furthermore, Laino et al. proved that the relationship between the sizes of the upper and lower teeth depends on the ethnicity of the population studies and the gender suggesting that Bolton's ratio is not universally applicable across all population.
Ashley-Howe Analysis, indicated that Group A (patients with hypodontia) had significantly smaller basal arch width percentage (PMBAW %) when compared to control group with P < 0.05 indicating the greater need for expansion in patients with hypodontia and the lesser need for extractions. The intercanine and intermolar width was also reduced in Group A when compared to Group B. However, values when compared statistically were not significant (P > 0.05). This was in accordance with a study by Wisth et al. (acta scandol 1974) who concluded that neither the dental arch width nor the mesiodistal diameter of the teeth were significantly different in the hypodontia group compared to a control group without hypodontia.
Hence, when orthodontic treatment is performed on patients with hypodontia, not only the number but also the distribution of missing teeth should be taken into consideration. It must be notified that the treatment planning employed for patients with hypodontia must be considered for diagnosis, including profile, growth pattern, and esthetics of the patient. Depending on the proper diagnostic analysis, various treatment plans, namely stripping upper teeth, flaring of incisors, and slight increasing the overjet or overbite must take into consideration.
| Conclusion|| |
These findings suggest that the hypodontia patients have comparatively narrower mesiodistal tooth measurements (prominently in posterior segments) and reduced basal arch width as compared to control population. This indicates the greater need for expansion in patients with hypodontia and preponderance toward nonextraction methodology.
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Conflicts of interest
There are no conflicts of interest.
| References|| |
Proffit WR. Contemporary Orthodontics. St. Louis, Calif: Mosby-Year Book Inc.; 1999. p. 296-325.
Kwon HJ, Jiang R. Development of Teeth- Tooth Agenesis and Hypodontia/Oligodontia/Anodontia. Buffalo, New York, United States: Elsevier, Reference Module in Biomedical Sciences; 2018.
Ramazanzadeh BA, Ahrari F, Hajian S. Evaluation of tooth size in patients with congenitally-missing teeth. J Dent Res Dent Clin Dent Prospects 2013;7:36-41.
Rakhshan V. Congenitally missing teeth (hypodontia): A review of the literature concerning the etiology, prevalence, risk factors, patterns and treatment. Dent Res J (Isfahan) 2015;12:1-3.
Arte S. Phenotypic and Genotypic Features of Familial Hypodontia. PhD Thesis. Institute of Dentistry, University of Helsinki, Finland; 2001.
Gomes RR, da Fonseca JA, Paula LM, Faber J, Acevedo AC. Prevalence of hypodontia in orthodontic patients in Brasilia, Brazil. Eur J Orthod 2010;32:302-6.
Acev DP, Gjorgova J. Prevalance of hypodontia in the permanent dentition of Macedonian population. Balk J Dent Med 2014;18:93-8.
Larmour CJ, Mossey PA, Thind BS, Forgie AH, Stirrups DR. Hypodontia – A retrospective review of prevalence and etiology. Part I. Quintessence Int 2005;36:263-70.
Polder BJ, Van't Hof MA, Van der Linden FP, Kuijpers-Jagtman AM. A meta-analysis of the prevalence of dental agenesis of permanent teeth. Community Dent Oral Epidemiol 2004;32:217-26.
Patil S, Doni B, Kaswan S, Rahman F. Prevalence of dental anomalies in Indian population. J Clin Exp Dent 2013;5:e183-6.
Shetty P, Adyanthaya A, Adyanthaya S, Sreelatha SV. The prevalence of hypodontia and supernumerary teeth in 2469 school children of the Indian population: An epidemiological study. Indian J Stomatol 2012;3:150-2.
Han C, Dai J, Qian H, Chen L, Wang Y, Huo N, et al
. The application of bolton's ratios in orthodontic treatment planning for Chinese patients. Open Anthropol J 2012;3:65-70.
Al-Ani AH, Antoun JS, Thomson WM, Merriman TR, Farella M. Hypodontia: An update on its etiology, classification, and clinical management. Biomed Res Int 2017;2017:9378325.
Brook AH, Elcock C, al-Sharood MH, McKeown HF, Khalaf K, Smith RN. Further studies of a model for the etiology of anomalies of tooth number and size in humans. Connect Tissue Res 2002;43:289-95.
Brook AH, Elcock C, Aggarwal M, Lath DL, Russell JM, Patel PI, et al.
Tooth dimensions in hypodontia with a known PAX9 mutation. Arch Oral Biol 2009;54 Suppl 1:S57-62.
Mirabella AD, Kokich VG, Rosa M. Analysis of crown widths in subjects with congenitally missing maxillary lateral incisors. Eur J Orthod 2012;34:783-7.
Yaqoob O, DiBiase AT, Garvey T, Fleming PS. Relationship between bilateral congenital absence of maxillary lateral incisors and anterior tooth width. Am J Orthod Dentofacial Orthop 2011;139:e229-33.
Brook AH, Griffin RC, Smith RN, Townsend GC, Kaur G, Davis GR, et al.
Tooth size patterns in patients with hypodontia and supernumerary teeth. Arch Oral Biol 2009;54 Suppl 1:S63-70.
McKeown HF, Robinson DL, Elcock C, al-Sharood M, Brook AH. Tooth dimensions in hypodontia patients, their unaffected relatives and a control group measured by a new image analysis system. Eur J Orthod 2002;24:131-41.
Ooshima T, Ishida R, Mishima K, Sobue S. The prevalence of developmental anomalies of teeth and their association with tooth size in the primary and permanent dentitions of 1650 Japanese children. Int J Paediatr Dent 1996;6:87-94.
Schalk-van der Weide Y, Bosman F. Tooth size in relatives of individuals with oligodontia. Arch Oral Biol 1996;41:469-72.
Wisth PJ, Thunold K, Böe OE. Frequency of hypodontia in relation to tooth size and dental arch width. Acta Odontol Scand 1974;32:201-6.
Chung CJ, Han JH, Kim KH. The pattern and prevalence of hypodontia in Koreans. Oral Dis 2008;14:620-5.
Ben-Bassat Y, Brin I. Skeletodental patterns in patients with multiple congenitally missing teeth. Am J Orthod Dentofacial Orthop. 2003;124:521-5.
Tavajohi-Kermani H, Kapur R, Sciote JJ. Tooth agenesis and craniofacial morphology in an orthodontic population. Am J Orthod Dentofacial Orthop 2002;122:39-47.
Smith SS, Buschang PH, Watanabe E. Interarch tooth size relationships of 3 populations: “does Bolton's analysis apply?”. Am J Orthod Dentofacial Orthop 2000;117:169-74.
Laino A, Quaremba G, Paduano S, Stanzione S. Prevalence of tooth-size discrepancy among different malocclusion groups. Prog Orthod 2003;4:37-44.
[Table 1], [Table 2], [Table 3], [Table 4]