DEEP BITE MALOCCLUSION: EXPLORATION OF THE SKELETAL AND DENTAL FACTORS

Baleegh Abdulwahab Galeb Ahmed Alaklany1image, Fuad Lutf Almotareb1image, Strallah Hussin Abdullah Albaham1image, Hassan Abdulwahab Al-Shamahy2,3image, Amani Hussein Y Al-hamzi3image 

1Orthodontics, Pedodontics and Prevention Department Faculty of Dentistry, Sana'a University, Yemen.

2Department of Basic Sciences, Faculty of Dentistry, Sana’a University, Republic of Yemen.

3Medical Microbiology department, Faculty of Medicine, Genius University for Sciences & Technology, Dhamar city, Republic of Yemen.

ABSTRACT 

Background and objective: A deep bite malocclusion may be due to skeletal and dental factors. The analysis of the etiological factors may have an influence on the treatment plan. The aim of this study was to exploration the most common dental and skeletal factors that contribute to deep bite malocclusion in Yemeni individuals, as well as the correlations between them.

Material and methods: a cross-sectional prospective study was conducted to evaluate 136 individuals with deep bites using study casts and lateral cephalometrics (62 males and 74 females), with ages ranging from 18 to 28 years, with the Onyx program used for analysis. The recorded data was collected, tabulated, and statistically analyzed by SPSS.

Results: The Gonial angle and Jarabak index form the highest contribution to skeletal deep bite (59.3%), and the least contributing factors were the decreased saddle angle (3%), followed by decreases in the inclination angle) Pn line- PP) (11.1%). On the other hand, the most contributing dental factor to the deep bite was an exaggerated curve of spee (63.5%), followed by a decreased clinical crown length of the Lower first molar (52.6%), and the least contributing dental factor was an increased clinical crown length of the maxillary incisors. There was more correlation between skeletal factors than dental factors.

Conclusion: Deep bite malocclusion was characterized mostly by counterclockwise rotation of the mandible and increased spee curve. Understanding the most common dental and skeletal contributors will help clinicians treat patients with deep malocclusions more successfully.

Keywords: deep bite, dental factors, skeletal factors, Yemen.

 

INTRODUCTION

 

Malocclusion is a widespread problem of the oral cavity around the world, children and adults suffer from it, and it is no less important than other oral problems. Although malocclusion is not a life-threatening condition, the poor condition of the gums and masticatory impairment associated with DBM raises the need to explore the prevalence of malocclusion in different age groups1-3. Deep malocclusion (DBM) is understood as a type of malocclusion that can have a complex etiology, necessitating elaborate and careful differential diagnosis, and which can be exacerbated when the overbite of the upper incisors over the lower incisors exceeds one-third of the crown of the lower incisors in central occlusion and is seen regularly cases of this type of malocclusion frequently4. According to Proffit5, an overbite greater than 5 mm is present in approxi-mately 20% of children and 13% of adults” and contributes to approximately 95.2% of vertical occlusal disorders. DBM may result from either intrinsic or acquired factors such as condyle growth pattern and skeletal pattern and malocclusion. Acquired characteristics such as muscular habit, tooth position changes, loss of posterior abutment teeth, and lateral tongue thrust.  DBM is multifactorial in nature and is classified depending on the causes as genetic and environmental factors1,6; others classified it as dental or skeletal in origin7. Dental deep bite (DDB) is associated with an increase in the spee curve. DBM has been associated with higher oral root torque of the upper incisors. In addition, it had favorable associations with DBM which are the anterior maxillary and maxillary basal elevations, the anterior maxillary and maxillary mandibles, and the posterior maxillary and mandibular maxillary elevations. Extraction of the lower incisors causes the arch to collapse, deepening the bite7. A skeletal deep bite (SDB) might be the consequence of an inconsistency in the cant, mandible, or maxilla's vertical orientation. According to a few studies, the vertical component of mandibular growth has a more significant impact than the rotational component. Mandibular skeletal changes were also twice as important as mandibular dental changes and roughly 2.5 times as important as maxillary changes in causing overbite changes1,2.

Patients with small DBM often do not require treatment unless the patient requests it for aesthetic reasons. On the other hand, severe DBM causes problems with periodontal disease and tooth wear, as well as traumatizing the incisive papilla and interfering with mastication function. It must be treated clinically with orthodontic or surgical intervention after knowing the causes. Various procedures for DBM correction have been developed in orthodontics8,9.  DBM is one of the occlusal defects that are difficult to treat and maintain after orthodontic treatment. However, any treatment must be carefully designed for each patient based on the aetiology of the malocclusion and investigation of the active ingredients. Treatment failure is prevalent when the etiologic variables are not accurately identified10. Studies on dental health problems in Yemen are still modest and limited, although there are studies that dealt with the problems of tooth decay, gum infections, the causes of permanent tooth extraction, and the prevalence and pattern of impaction of the third molar in adults and children, in oral microbiology and pathology, and drug resistance11-31; but no research has investigated  the most common dental and skeletal factors that contribute to DBM etiology in Yemeni adults prior to this study. The goal of this study was to identify the most common dental and skeletal factors that contribute to DBM in Yemeni individuals, as well as the correlations between them using lateral cephalograms and study casts.

 

MATERIALS AND METHODS 

 

This was a cross-sectional study conducted to explain the skeletal and dental factors of DBM in a sample of Yemeni individuals using skeletal and dentoalveolar measurements (Table 1, Table 2 and Figure 1, Figure 2, and Figure 3). The sample was taken from Sana'a University students, where the study included 136 participants, 74 (54.4%) of whom were females, while 62 participants (45.6%) were males between the ages of 18 and 28 years. Selection was made according to the inclusion criteria as follows: Yemeni nationality, no previous orthodontic or prosthodontic treatment, complete permanent teeth with a vertical bite greater than 5 mm when the teeth are in central occlusion.; no systemic disease or craniofacial abnormalities, premolars were fully erupted, there were no extra teeth or missing teeth, the study cast was unaffected and of acceptable quality. The study's objective was explained to each participant, and each one signed an information and consent form.

Lateral cephalogram: Alginate and impression material was used to create diagnostic casts of the maxillary and mandibular arches. The dentist stone poured the alginate impression, and a model was made. 

Linear parameters were measured using digital Vernier calipers (0-150 mm) with a manufacturer-specified reliability of 0.01 mm and accuracy of 0.02 mm to reduce the probability of error. 11 radiographs and 11 casts of all individuals was analysis twice at a two-week interval and an error analysis was performed. 

Data analysis: For data analysis, SPSS version 19.00 was utilized, the frequencies, averages, and standard deviations of numerous skeletal and dental deep bite etiological components were calculated using descriptive statistics. Using the Pearson correlation coefficient, all of these values were associated. Statistical significance was defined as a p-value of 0.05 or lower.

 

RESULTS

 

Frequency of the Skeletal factors in a deep bite:  Among the skeletal factors in Table 3, the Gonial angle (Ar-GO-Me) and Jarabak index (ratio of PFH to AFH) form the highest contribution to skeletal deep bite malocclusion was 59.3%, followed by decreases in lower anterior facial height in relation to upper anterior facial height (LAFH/UAFH) in 53.3% , decreased posterior facial height  was 52.6 %, and decreased lower anterior facial height in relation to total anterior facial height was 50.4%), increases upper anterior facial height  was in 44.4%, decreases the basal angle, which is between maxilla and mandible  occurred in 40.7%, decreases the Sum of Bjork, increases the Ramus length (Ar-Go) occurred in 31.9%, and decreases  angle between FH-MP was 28.1%.  On the other hand, the least contributing factor to skeletal deep bite malocclusion was the decreased saddle angle (3 %) followed by clockwise rotation of the maxilla ( decreases inclination angle ) (11.1%), increases total anterior facial height (15.6%) , decreases articular angle (17.5%), decreases lower anterior facial height (ANS-Me) (18.5%), and decreases angle between anterior cranial base and mandible (20.7%).

Frequency of the dental factors in a deep bite: Among the dental factors (Table 4), an exaggerated curve of Spee showed the highest contribution to dental deep bite malocclusion was 63.5%, followed by decreased clinical crown length of the mandibular buccal segment with 52.6%, and then by decreased distance from the mesial cusp tip of the lower first molar to the mandibular plane (under eruption of the mandibular buccal segment), which formed 48.9%. Then there was over eruption of the upper incisors in 40%, retroclination of the maxillary incisors and a decrease in length of the maxillary posterior segment in 31.1%, under eruption of the maxillary posterior segment was 30.4%, over eruption of the mandibular incisors was 28,9%, increased clinical crown length of the mandibular incisors was in 25.2%, retroclination of the mandibular incisors (17%), and the least contributing factor was the increased clinical crown length of the maxillary incisors  with 8.1%.

Correlations between skeletal factors:  Several skeletal deep bite factors were correlated by using Pearson correlation coefficient as show in Table (5), this correlation divided into:

1. Perfect positive correlation: Correlations between FH-MP and PP-MP (r=0.809 p=0.01), Sn-MP (r=0.864 p=0.01), and Sum of Bjork (r=0.801 p=0.01), as well as PP-MP and Sn-MP (r=0.807 p=0.01) and Sn-MP and Sum of Bjork (r=0.943 p=0.01).

 2. Strong positive correlation: Correlation between Ar-GO-Me and FH-MP (r=0.666, p=0.01), PP-MP (r=0.648,  p=0.01), Sn-MP (r=0.647, p=0.01), sum of Bjork (r=0.689, p=0.01), between PP-MP and  sum of Bjork (r=749, p=0.01), between Jarabak index and PFH (r=0.715,  p=0.01), Ar-Go (r=0.703,  p=0.01), between TAFH and UAFH (r=0.649,  p=0.01), LAFH (r=0.798,  p=0.01), PFH (r=0.501,  p=0.01),  between LAFH and LAFH/TAFH (r=0.551,  p=0.01), LAFH/UAFH (r=0.705,  p=0.01), between LAFH/TAFH and LAFH/UAFH (r=0.760,   p=0.01).

 3. Moderate positive correlation:  Correlation between FH-MP and TAFH (r=0.317,  p=0.01), LAFH (r=0.320,  p=0.01), between PP- MP and LAFH/UAFH (r=0.433,  p=0.01), Inclination angle (r=0.328  p=0.01), ANS-Me (r=0.359, p=0.01), between Sn-MP and TAFH (r=0.303,  p=0.01), between TAFH and Ar-Go (r=0.345,  p=0.01), between LAFH and PFH (r=0.461,  p=0.01), Ar-Go (r=0.348,  p=0.01), between LAFH/TAFH and Inclination angle (r=0.420,  p=0.01), between UAFH and PFH (r=0.429,  p=0.01).

4. Weak positive correlation: Correlation between FH-MP and Sar- Ar GO (r=0.187  p=0.05), LAFH/UAFH (r=0.228,  p=0.01), between PP- MP and TAFH (r=0.196, p=0.05), LAFH/TAFH (r=0.278, p=0.01), between Sn-MP and ANS-Me (r=0.202,  p=0.05), between Sn-Sar with N-ANS (r=0.228,  p=0.01), Ar-Go (r=0.173,  p=0.01), between the Ar-GO-Me and LAFH/UAFH (r=0.216,  p=0,05),and between TAFH and LAFH/UAFH (r=0.201,  p=0.05), between UAFH and Ar-Go (r=0.295,  p=0.01), between LAFH and Inclination angle (r=0.224,  p=0.01), between Sum of Bjork and  TAFH (r=0.225,  p=0.01), ANS-Me (r=0.195,  p=0.05).

5. Perfect negative correlation: Correlation between Jarabak index and FH-MP (r=-0.8, p=0.01), Sn-MP (r=-0.910, p=0.01), Sum of Bjork (r=-0.913, p=0.01), TAFH (r=-0.195, p=0.05), between Sn-MP and PFH (r=-0.551, p=0.01).

6. Strong negative correlation: Correlation between FH-MP and Ar-Go (r=-0.524  p=0.01), between the with Jarabak index (r=-0.777, p=0.01), Sar-ArGO (r=-0.542,  p=0.01), between Ar-GO-Me and Jarabak index (r=-0.620,  p=0.01), PFH (r=-0.536,  p=0.01), between Sum of Bjork and PFH (r=-0.610,  p=0.01), Ar-Go (r=-0.562,  p=0.01), between UNFH with LAFH/UAFH ( r=-0.554,  p=0.01), between Sn-MP and PFH (r=-0.589,  p=0.01), Ar-Go (r=-0.562,  p=0.01).

7. Moderate negative correlation: Correlation between FH-MP and PFH (r=-0.481 p=0.01), between Sar-ArGO and Ar-GO-Me (r=-0.356, p=0.01), between Ar-GO-Me and Ar-Go (r=-0.433, p=0.01), between UAFH and LAFH/TAFH (r=-0.436, p=0.01).

8. Weak  negative correlation: Correlation between FH-MP and Sn-Sar (r=-0.248,  p=0.01), between PP- MP and Sn-Sar (r=- 0.209,  p=0.05), N-ANS (r=-0.217,  p=0.05), between Sn-MP and Inclination angle (r=-0.175,  p=0.05), between Sn-Sar and Ar-GO-Me (r=-0.171,  p=0.05), LAFH/TAFH (r=-0.204,  p=0.05), LAFH/UAFH (r=-0.270,  p=0.01), Ar-Go (r=-0.173,  p=0.05), between Ar-GO-Me and LAFH/UAFH (r=-0.216,  p=0.05), between Sum of Bjork with Inclination angle (r=-0.181,  p=0.05).

Correlations between dental factors:

From Table 6, it was noticed that there were few correlations between the dental factors, this correlation divided in to:

1. Strong positive correlation: Correlations between the distance of L1 to MP and U6 to PP (r=0.589, p=0.01), between U1 clinical crown length and L1 clinical crown length (r=0.538, p=0.01).

2. Moderate positive correlation: Correlations between the distance of L1 to MP and L6 to MP (r=0.419, p=0.01), between U6 clinical crown length and L6 clinical crown length (r=0.403,  p=0.01).

3. Weak positive correlation: Correlations between Distance U6 to PP and distance L6 to PP (r=0.193, p=0.05), between The angle of U1-PP and the angle of L1-MP (r=0.299,  p=0.05), between U1 clinical crown length and L6 clinical crown length (r=0.260, p=0.01), curve 0f spee (r=0.263, p=0.01), between L1 clinical crown length and U6 clinical crown length (r=0.226, p=0.01), L6 clinical crown length (r=0.268, p=0.01), curve of spee (r=0.212 p=0.05).

4. Weak negative correlation:  Correlation between the distance of L1 to MP and U1-PP (r=-296, p=0.01).

 

DISCUSION

 

This study defining the relationship between dental, skeletal and recurring factors causing DBM. While other studies by Fatahi et al.32, Azeem,10, and Joshi et al.,33, only investigated the frequency of the causative factors of DBM. However, it was found that the retrospective studies conducted by El-Dawlatly et al.8, Bhateja34, and Barman35, agree with the current study on investigation the frequency of factors causing DBM and determine the correlation between dental and skeletal factors. The present study include N=136 participants (male=62; female=74); based on a sample size formula. Their ages range from 18 to 28 years. Fattahi et al.,32 studied 170 patients divided into normal and DBM groups, with mean age for cases equal to 19.6 ±5.9 years and for control was 20.6 ±5.7 years. Bhateja34 examined the skeletal and dental aspects of DBM in 113 participants (35 men and 78 women). Azeem10 include 100 DBM subjects (female=60, male=40) in order to assess the frequency of dental and skeletal factors. Joshi et al.,33 evaluated and compared the skeletal and dental factors of DBM with a normal occlusion. Joshi et al.,33 examined samples from the first and second groups, each with 50 participants. The study by Barman35 include113 participants (35 men and 78 women) for the examination and evaluation of dental and skeletal factors in DBM. The present study, like earlier ones, used software programs for analysis. However, in their work, Fatahi et al.,32 used manual cephalometric analysis. Software programs are considered to be more precise during analysis and to produce more reliable results than manual tracing.

Despite the fact that some studies El-Dawlatly et al.,8, Bhateja34, Azeem10, Joshi et al.,33, and Barman35 included the curve of spee in addition to the clinical crown length of the upper and lower central incisors on the dental casts and ten variables on the cephalometric, with the exception of Azeem10, which only included five variables on the cephalometric, and  As a result, the present study has advantages over these studies because it included five measurements on the dental cast and twenty-two on the cephalometric, which was similar to a study by Fatahi et al.,32 that included five measurements on the dental cast and twenty-three on the cephalometric. However, one measurement from that study—the Ramus/FH angle—was excluded from the present study because it could not be found in the Onyx program that was used to analyze the sample. Correlation between different factors in a deep bite: Pearson correlation coefficients determine the strength of the relationship between two factors.Correlation between factors reveals that as one factor changes in value, the other tends to change in a particular direction. Understanding this relationship is useful because we can use the value of one factor to predict the value of the other. Use El-Dawlatly et al.8, Bhateja34, and Barman35 correlates between different DBM components and showed that U1 clinical crown length has a statistically significant positive relationship with L1 clinical crown length, which is consistent with the results of the current study, which mentioned that there is a positive correlation between the overeruption of the maxillary and mandibular incisors highlights the necessity for careful consideration of mandibular incisor intrusion in the majority of individuals before maxillary incisor intrusion, and vice versa. The physician would benefit from the ability to equally divide the necessary intrusion between the maxillary and mandibular incisors, avoiding higher ranges of intrusive mechanics that could increase the risk of root resorption and compromise stability. This correlation provides the orthodontist with some recommendations that could aid in the more effective treatment of certain malocclusions. In addition, the findings of present study agree with those of Bhateja34, and Barman35, who found that there is a statistically significant positive connection between the mandibular plane angle and the gonial angle.

Frequency of skeletal factors in a deep bite: According to the findings of present study, decreases in gonial angle were the most common skeletal factors contributing to DBM, while decreases in saddle angle (Sn-Sar) were the least common skeletal factor of DBM. This was in agreement with the findings of El-Dawlatly et al.,8, Bhateja34,   Azeem10, and  Barman35 regarding the most common skeletal factors and not in agreement regarding the least common skeletal factors contributing to DBM. These studies found an increase in the SN-MP. This discrepancy can be explored by the fact that these previous studies did not include saddle angle (Sn-Sar) in their variables. In addition, the current study did not include SN-MP, the reason being that this angle was not found in the Onyx software that was used for the analysis. This is one of the shortcomings of the current study, as well as some other studies in this field did not include this angle, such as Fatahi et al.,32 and Joshi et al.,33.

There are other differences with the present study, such as decreases in mandible plane angle (FH-MP) were considered common skeletal factors of DBM after gonial angle8,10,34,35, but this is not in agreement with the findings of present study, which regarded basal angle (PP-MP), sum of Bjork, and Ramus length (Ar-Go) as common skeletal factors of DBM after gonial angle, respectively. This difference is significant because the present investigation is more thorough than these early studies, which left out certain important variables. It should be noted that growth modification is the preferred treatment for growing patients who have SDB. The cervical vertebral maturation index (CVM) can be used to gauge a child's growth stage36. It has been demonstrated that deep-bite growing subjects reach their maximal pubertal growth alterations two years after open-bite subjects37. As a result, growth manipulation should be tried in the latter stages of the pubertal growth spurt.

Frequency of Dental factors in a deep bite : This study demonstrated that the exaggerated curve of Spee had the highest contributing factor among all dental factors of DBM, which agrees with the investigation of studies by El-Dawlatly et al.,8  Fatahi et al.,32, Bhateja34, Azeem10, Joshi et al.,33, Barman,35, and Jhalani et al.,38. The present study emphasizes how important the mandibular dentoalveolar factors in DBM. It has been established that every 1mm of posterior extrusion increases the bite anteriorly by 1.5 mm, this discovery demonstrates that a small amount of molar extrusion can result in a considerable anterior bite opening39.

The second-highest contributing dental factor to DBM in the present study was a decrease in the clinical crown length of the lower posterior teeth. This does not agree with studies by Fattahi et al.,32 Bhateja34, Azeem10, and Barman35, that preferred to increase the clinical crown length of the upper incisors. Also, it does not agree with studies by El-Dawlatly et al.,8 and Joshi et al.,33 in which the upper incisor over-eruption is the second-highest contributing dental factor to DBM. Increases in the clinical crown length of the upper incisors are the least common dental causes of DBM in the current study, followed by a decrease in the inclination of the lower incisors and an increase in the clinical crown length of the lower incisors. This did not agree with the studies by El-Dawlatly et al.,8 Bhateja34, Azeem10, and Barman35, who found the increase in the clinical crown length of the lower incisors as the least contributing dental factors in the DBM, but agreed with a decrease in the lower incisor tilt (L1/ MP) as the second lowest contributing dental factor to DBM. Although the degree of parasitism depends on a number of factors to minimize complications on facial appearance. Upper incisor intervention was recommended by Burston as the best treatment option for DBM in his study40. Zacharisson41 said that the amount of upper incisors that appear when smiling and when at rest determines the appropriate treatment; the maxillary incisor width is best treated by intrusion the upper anterior teeth. Intrusions of the lower anterior teeth or posterior teeth are better treatment options for patients with moderate or low maxillary incisor width. For patients with DBM, the smile arch is used as a design guide for developing customized treatment programmes. Intrusion of the upper front teeth is not recommended for those with a flat smile arch.

Limitation of the study

It is clear that the current study has limitations as this study is not representative of the entire Yemeni population. Hence, further research is required to measure the causative factors of deep bite on a larger sample on a community basis, reliability in all measurements with the exception of the articular angle (Sar-ArGO), where the p-value was 0.025. The cause may have been due to superimposition in the condylar area with poor sharpness in lateral cephalometric. The Ramus/FH angle—was excluded from the recent study because it could not be found in the onyx program that was used to analyze the sample.

 

CONCLUSION

 

The gonial angle and jaraback ratio were the two skeletal characteristics that contributed the most to a deep bite, showing the significance of ramus growth and angulation in a growing deep bite. The skeletal elements that were least frequently shared in deep bite malocclusions included decreases in saddle and inclination angles. The most important dental component was a deep Spee curve, supporting the significance of mandibular incisor intrusion in deep bite mechanotherapy. A decreased clinical crown length of the lower first molars was the second highly contributing dental component in DBM. Among the least shared dental elements in deep bite malocclusions were lengthening of the upper and lower incisors' clinical crowns and lingual inclinations of the mandibular incisors. There were many correlations between the skeletal components, more than those in the dental ones.

 

ACKNOWLEDGEMENTS 

 

The authors thank the Faculty of Dentistry, Sana'a University, Sana'a, and Yemen for their generous support. 

 

CONFLICT OF INTEREST 

 

No conflict of interest associated with this work.

 

AUTHOR’S CONTRIBUTIONS 

 

This research is part of a master's degree in the Orthodontics, Pedodontics and Prevention Department, Faculty of Dentistry, Sana’a University, Yemen, first author Baleegh Alaklany, who conducted field work, and who did clinical work and other authors contributed to data analysis, drafting and review of the paper, and gave final approval to the research. 

 

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