Retrospective Epidemiological Study of the Width of Maxillary Diastema in Patients from Northeastern Bulgaria

study of the width of maxillary


INTRODUCTION
Maxillary diastema (MD) occurs when the gap between the central incisors exceeds 0.5 mm.It is an a and phonetic issue that is most usually seen in mixed dentition but less frequently occurs in permanent dentition.It is caused by pathogenic and iatrogenic conditions, as well as those affecting jaw growth.Many researchers have investigated the frequency of MD in the community, yielding results ranging from 1.60% to 25.40% in various populations.[3][4] The prevalence of MD varies substantially with age, sex, studied population, and racial origin.Lavelle's 1970 study in the United Kingdom found that the Negroid-Australoid race had the highest frequency of MD (5.5%), followed by Caucasian individuals (3.4%), and the Mongoloid race had the lowest prevalence (1.7%). [5]In 1999, Oesterle and Shellhart found it in 97% of the 5-year-olds they evaluated with the frequency dropping dramatically with age. [6]

AIM
We conducted a retrospective study to investigate the epidemiology of maxillary diastema in patients from northeastern Bulgaria.

MATERIALS AND METHODS
The study was carried out in accordance with the guidelines of the Medical University's Ethics Committee in Varna, Bulgaria (No. 116/28.04.2022).For this investigation, 149 diagnostic plaster models of individuals with maxillary diastema were examined.All subjects sought dental care from specialized prosthodontic offices due to a concerns.The investigated patients had a mean age of 39.50±1.70 years.The study included 73 male models (mean age: 45.64±1.92)and 76 female models (mean age: 33.59±2.04years).For accurate analysis, the patients were separated into two age groups.The first age group consisted of people aged 35 and under.In the second category, we included patients over 35 years.
The selection of models was carried out according to the criteria for inclusion in the experimental study (Table 1).
To obtain the plaster models, impressions were taken using condensation silicone impression material (Zeta Plus Putty and Oranwash, Zhermack, Italy), to overcome the retention of intact frontal teeth with maxillary diastema.To neutralize the negative effect of polymerization shrinkage, the plaster models were left to set for up to three hours from the moment the impressions were taken, following the manufacturer's instructions.The models were cast with class IV gypsum (WellsaStone IV, Wellsamed, Germany), using the reverse pouring method.For maximum precision, a digital caliper Microtech BIG SCREEN, IP54, 300 mm, 0.01 mm, certified for calibration No. M2212-1941 dated 19.12.2022, was used.The distance was measured between the most prominent points on the mesial approximal surfaces of the central incisors.The width of the frontal teeth was recorded as the greatest distance between the mesial and distal contact points, in a plane perpendicular to the longitudinal axis of the tooth being measured.To justify our decision to conduct the retrospective study on plaster models, we examined the obtained data on the width of the MD from 50 patients, measured intraorally, on plaster models, and on a virtual working models.The obtained values for the width of the MD from 50 patients, measured intraorally, on a plaster model, and on a digital diagnostic model, did not show a statistically significant difference (p=0.000) (Fig. 1).

Size of MD according to sex
The derived 95% confidence interval shows that in the group of patients who met the selection criteria in the study, with 95% certainty, the width of the MD was expected to be in the range of 1.389 to 1.754 mm.According to the data from the studied models, the average value of the MD size in males was 1.57±0.78mm.The median of the MD

Inclusion criteria Exclusion criteria
Age width in males was 1.45±0.78mm.The smallest measured value of the MD in males was 1.09 mm, and the largest was 7.88 mm.The analysis of the results in females shows an average value of MD of 1.43±0.24mm and a 95% confidence interval of 1.37 to 1.48 mm.The median MD width in females was 1.41±0.24mm.This value is remarkably close to the value obtained for males.The smallest measured value of MD in females was 1.05 mm, and the largest was 2.34 mm.The obtained standard errors were negligibly small, ensuring the reliability of the results and allowing the generalization that at the lower limit, the value of the measured MD widths in both sexes in the studied group was very close (males: 1.38 mm; females: 1.37 mm).

Size of MD according to age
The analysis of the data shows that in individuals ≤35 years old, the average size of MD is 1.43±0.24mm.The derived 95% CI indicates that patients from northeastern Bulgaria, meeting the inclusion criteria for the study, are characterized by MD widths ranging from 1.37 to 1.50 mm.The value of the median MD width in the studied group is 1.41±0.24mm.The smallest measured value of MD width in individuals ≤35 years old is 1.07 mm, and the largest is 2.20 mm.
Individuals over 35 years old had an average MD size of 1.544±0.72mm, with a 95% confidence interval ranging from 1.391 to 1.696 mm.The median MD width among these participants was 1.44±0.72mm.The smallest measured value of MD in those over 35 years old was 1.05 mm, while the maximum was 7.88 mm.
The median value for the 149 models evaluated was 1.46±0.23 mm.The data analysis revealed no linear correlation between the age of the examined units and the size of the MD.Thus, non-parametric correlation coefficients were applied.After evaluating the results, a Kendall's tau coefficient of 0.123 (significant at α=0.05) and a Spearman's rank correlation coefficient of 1.148 (significant at α=0.05) were found.A positive but weak correlation was found between the age of the examined patients and the size of MD.The diastema widens with age.

DISCUSSION
The processed data from our study show that the average size of MD in the studied male patients (1.57mm) was larger than that in the studied female patients (1.43 mm).Similar results were also reported by Sękowska and Chałas. [7]Several researchers analyzed the prevalence of MD and reported different results.This is due to the fact that the epidemiology of MD is directly related to the ethnicity, race, and age of the studied patients.Logeswari et al. investigated 500 individuals aged 18-35 years in Chennai, India.They reported a prevalence rate of 21.8%, with no statistically significant association between sex and the presence of MD. [8] In 2020, a similar study was conducted in Southern Kurdistan by Hasan et al.They examined 1000 individuals with a mean age of 19 years, evenly distributed between both sexes.They observed MD when the distance between the maxillary incisors was greater than 0.5 mm in 23.2% of the studied patients.The authors indicate a significantly higher frequency in females (26.4%) compared to males (20.3%). [9]A study from 2010 aiming to analyze the prevalence of orthodontic malformations in the Turkish population reported a frequency of maxillary diastema of 4.5%, distributed equally between both sexes.Celikoglu et al. investigated 1507 orthodontic patients, including 884 women and 623 men.They found that maxillary diastema was more common in women, while mandibular diastema is more common in men.They also noted that diastema was transmitted through generations and was more likely to be inherited by male children. [10]

CONCLUSION
Today's society places a high value on patients' dental as and smiles.This leads to a focus on tiny details such as the distance between central incisors and a desire to fix them.
Despite the availability of many procedures, prosthetic methods remain preferred due to the long-term nature of treatment, ease of execution, and predictable results.Studying the width of MD based on sex and age allows for a rapid selection of materials and construction procedures, resulting in superior functional and a outcomes from the treatment.

4 Figure 1 .
Figure 1.Measuring MD on plaster models, on digital diagnostic models, and intraorally.