The prevalence and severity of malocclusions in transfusion-dependent thalassemic patients of the age group 12–17 years was done as this is a common age when orthodontic treatment is sought. The TPI was selected for this evaluation as it has proved to be a useful epidemiological indicator of malocclusion . It has been found to be highly reproducible and valid . Application of the TPI is practicable and requires less clerical time when compared with the Occlusal Index (OI) . Thus, the TPI is a useful index for measuring need for treatment and as an aid in the identification of children who can benefit most from orthodontic treatment .
The present study reported a ratio of 1:1.25:0.01 between angle Classes I, II, and III malocclusion, respectively, in the thalassemia group which contrasted to a normal population ratio of 5.2:1:0.01. Pusaksrikit et al. reported the ratio between various angle classes, i.e., I, II, III as 2.7:1:0 which contrasted to a normal population pattern of 3:1:1 .
Giuseppina in a study reported Class I, II, III malocclusions, and asymmetries in 40.4, 29.2, 3.2 and 27.1 % of the sample, respectively. The objective need for orthodontic treatment (grades 4 and 5 of IOTN) was registered in 1077 subjects (41.2 %) .
The higher prevalence of Class II malocclusion in thalassemic children in the past has been attributed both to marrow hyperplasia occurring due to chronic anemia, resulting in maxillary prominence and also due to mandibular retrusion occurring because of generalized growth retardation in the thalassemic children by different authors [20–23].
In the present study, the assessment of malocclusion using TPI scores in normal population shows no or minor malocclusion in 77 % cases. This is similar to results of studies by Bhardwaj et al., Shivakumar et al., Esa et al., and van Wyk et al. These studies using Dental Aesthetic Index scores show no or minor malocclusion in the range of 60 to 80 % in the normal population [24–27]. Ugur et al. conducted a study to evaluate the prevalence of malocclusion and to assess the need for orthodontic treatment among 6–10-year-old Turkish primary school children. The TPI was used to record and measure the malocclusions; 40.38 % of the observed population showed normal occlusion, 21.85 % had minor manifestations of malocclusion and treatment need was slight, 25.17 % of the subjects showed definite malocclusion, 7.54 % had severe malocclusion, and 5.06 % had a very severe handicap with a mandatory treatment requirement. Thus, according to this study, there is definite need for orthodontic treatment in 37 % of individuals .
The present study indicates that 68 % of the thalassemic patients definitely need orthodontic treatment which is 18 % for normal population. Comparison with any of the previous studies show that the prevalence of malocclusion in thalassemic patients is also much more than that in the normal population. The assessment of treatment needs revealed a higher prevalence of handicapping and severely handicapping malocclusion in thalassemic patients compared to normal children. This necessitates the need for providing orthodontic treatment to these children.
In the present study, occurrence of Class III malocclusion was an interesting observation. It is difficult to explain this observation as there was no familial history and literature does not support the occurrence of Class III in thalassemic patients.
The present study was conducted in an environment where the patients are regularly transfused and transfusion is started at very early stages. The blood hemoglobin levels are regularly monitored and maintained. This decreases the extent of malocclusion. Thus, we may expect more severe malocclusions in other environments where the facilities for these patients are not very favorable. This may further increases the need for orthodontic treatment.