A Cephalometric Study of Cervical Vertebrae Maturation to Evaluate Mandibular Growth at Different Levels in Skeletal Class I and Class II Malocclusions

ABSTRACT

Aim:

This study aims to assess the different increments of mandibular growth with cervical vertebrae maturation (CVM) in skeletal class I and skeletal class II malocclusions by using lateral cephalograms.

Materials and Methodology:

The sample size comprised 200 (100 males and 100 females, aged 7–16 years) lateral cephalometric radiographs with class I and class II skeletal patterns. The linear measurements condylion-gonion (Co-Go) and condylion-gnathion (Co-Gn) were compared between skeletal class I and class II malocclusion, genders, and the correlation with different CVM stages according to Hassel and Farnan (1995). The results were statistically analyzed by the Newman–Keuls post-hoc test.

Results:

The mean Co-Gn and Co-Go showed a linear increase with the rise in maturation stages and was evidently higher in males than females. For Co-Gn, it is evidently higher in class I than class II and for Co-Go it is evidently higher in class II than class I malocclusion.

Conclusion:

Implementing treatments at CVM stages 2-3 or before 3-4 may normalize mandibular length and orientation across malocclusion types.

INTRODUCTION

The growth of the mandible and the anteroposterior relationship between the maxilla and mandible significantly influence the onset of malocclusion and its subsequent treatment. The timing for initiating treatment is crucial, particularly with functional appliances, as it is essential to consider the growth of condylar cartilage throughout the therapeutic process. Proper intervention at the right developmental stage can greatly improve treatment outcomes and patient satisfaction.[1,2,3]

This study was conducted in the Department of Orthodontics and Dentofacial Orthopaedics at Awadh Dental College and Hospital, Jamshedpur. The objective of this research is to evaluate the various increments of mandibular growth in relation to cervical vertebrae maturation (CVM) in both skeletal class I and class II malocclusions. Lateral cephalograms were utilized to ensure accurate measurement and analysis of the growth patterns. Understanding these relationships is vital for orthodontists to devise appropriate treatment strategies and improve the management of malocclusions in affected patients, thereby enhancing their overall dental health and functional occlusion.

MATERIALS AND METHODOLOGY

The sample size comprised 200 (100 males and 100 females) lateral cephalometric radiographs (patients aged between 7 and 16 years old and had never undertaken any orthodontic treatment). Tracing of lateral cephalograms was performed on acetate matte 0.003-inch tracing paper with an HB hard lead pencil.

Cervical vertebral stages (CVS) were determined according to the guidelines of Hassel and Farnan (1995)[4] and further modified by Lamparski (1972).[5] There are six maturational stages of the second to sixth cervical vertebrae bodies: Stage 1 (Initiation), Stage 2 (Acceleration), Stage 3 (Transition), Stage 4 (Deceleration), Stage 5 (Maturation), and Stage 6 (Completion). Significant skeletal growth occurs in the stages CVS 1-2, CVS 2-3, CVS 3-4, CVS 4-5, and CVS 5-6. Two hundred sample sizes were further divided into different stages of CVM from CVS1 to CVS6. An equal number of male and female subjects were selected to rule out sexual dimorphism. Selection of class II and class I sample subjects was done based on ANB (Point A Nasion Point B) angle (Class I: 2° ± 2°, Class II: >4°) and WIT’s appraisal (Skeletal Class I: the linear distance between AO and BO [AO: A perpendicular to occlusal plane, BO: B perpendicular to occlusal plane] is 2 to 4 mm in males and −4.5 to 1.5 mm in females. Skeletal Class II: greater than 4 mm in males and greater than 1.5 in females).

The main parameters assessed are: Co to Go: The measurement of the length of the ascending ramus is made by calculating the distance between the constructed gonion and condylion. Co to Gn: Rotation of the jaw bases is determined by the distance between condylion and anatomic gnathion. As for reliability, the linear measurements (Co-Gn, Co-Go) were assessed by two observers within one-week intervals.

Statistical analysis was performed on a software named “SPSS” (Statistical Package for the Social Sciences), Windows “version 17.0 (IBM Corporation, Route 100 Somers, NY).”

RESULTS

Linear measurements

The mean Co-Gn showed a linear increase with an increase in the maturation stage and was evidently higher in males than females and higher in class I than class II [Table 1]. The mean Co-Go showed a linear increase with an increase in the maturation stage and was evidently higher in males than females and higher in class II than class I [Table 2]. Correlation with age: on analysis of Pearson correlation, the result showed a positive and significant correlation of Co-Gn (r = 0.64, P < 0.001) and Co-Go (r = 0.51, P < 0.001) with age, suggesting that as age increases linear measurements increase.

Table 1.

Comparison of mean Co-Gn between CVM stages for each gender and skeletal pattern, by Newman–Keuls test

Comparison of stage	Female				Male
	Class I		Class II		Class I		Class II
	Mean diff. (mm)	P	Mean diff. (mm)	P	Mean diff. (mm)	P	Mean diff. (mm)	P
Stage 1 vs. 2	4	0.0051	5.3	0.0012	6.6	0.014	3.7	0.2198
Stage 1 vs. 3	7.8	0.0001	9.5	<0.0001	8.1	0.0018	7.1	0.0168
Stage 1 vs. 4	9	<0.0001	12.2	<0.0001	10	0.0019	10.8	0.0017
Stage 1 vs. 5	9.4	<0.0001	12.9	<0.0001	11.7	0.0001	12.4	0.0018
Stage 2 vs. 3	3.8	0.0374	4.2	0.0009	1.5	0.5487	3.4	0.0324
Stage 2 vs. 4	5	0.0074	6.9	0.0002	3.4	0.2639	7.1	0.012
Stage 2 vs. 5	5.4	0.004	7.6	0.0008	5.1	0.0613	8.7	0.0104
Stage 3 vs. 4	1.2	0.5363	2.7	0.1102	1.9	0.503	3.7	0.0673
Stage 3 vs. 5	1.6	0.4073	3.4	0.1027	3.6	0.1444	5.3	0.0535
Stage 4 vs. 5	0.4	0.8318	0.7	0.7597	1.7	0.5609	1.6	0.5407

Table 2.

Comparison of mean Co-Go between CVM stages for each gender and skeletal pattern, by Newman–Keuls test

Comparison of stage	Female				Male
	Class I		Class II		Class I		Class II
	Mean diff. (mm)	P	Mean diff.	P	Mean diff. (mm)	P	Mean diff.	P
Stage 1 vs. 2	4.7	0.0001	2.7	0.0048	4.7	0.0574	3.2	0.2182
Stage 1 vs. 3	5	0.0092	4.5	0.0002	4.6	0.004	4	0.0555
Stage 1 vs. 4	6.4	0.0001	7.1	<0.0001	5.7	0.0028	8.6	0.0001
Stage 1 vs. 5	7.1	0.0001	7.5	0.0003	9.2	<0.0001	9	0.0001
Stage 2 vs. 3	0.3	0.863	1.8	0.0824	0.1	0.969	0.8	0.7158
Stage 2 vs. 4	1.7	0.1984	4.4	<0.0001	1	0.7135	5.4	0.014
Stage 2 vs. 5	2.4	0.1123	4.8	0.0095	4.5	0.0684	5.8	0.0113
Stage 3 vs. 4	1.4	0.4727	2.6	0.0085	1.1	0.5786	4.6	0.0013
Stage 3 vs. 5	2.1	0.3127	3	0.0994	4.6	0.0043	5	0.0014
Stage 4 vs. 5	0.7	0.6791	0.4	0.8053	3.5	0.0491	0.4	0.6942

DISCUSSION

This study evaluated mandibular growth increments in relation to CVM, focusing on skeletal class I and class II malocclusions using lateral cephalometric radiographs. Our findings revealed significant trends associated with skeletal classification and sexual dimorphism.

We observed a linear increase in mean Co-Gn and Co-Go measurements correlating with maturation stages, affirming the relationship between mandibular growth and cervical vertebrae development, as suggested by Hassel and Farman (1995).[4] Notably, males exhibited significantly higher mean values than females, consistent with literature addressing sexual dimorphism during the adolescent growth spurt.

Our results align with O’Reilly and Yanniello (1988),[6] revealing that Co-Gn measurements were greater in class I malocclusion compared to class II. Conversely, Co-Go measurements indicated higher values for class II than class I, echoing findings from Bishara et al. (1997),[7] which elucidated differences in mandibular lengths according to malocclusion types. This study enhances understanding of the interplay between skeletal classification and growth patterns, offering valuable insights for developing orthodontic treatment strategies.

In conclusion, our results advance knowledge of how skeletal classification and CVM affect mandibular growth. This research equips clinicians with essential information for formulating personalized treatment plans and anticipating growth outcomes. Future investigations with larger, more diverse populations are crucial to confirm and expand upon these findings, further enriching the field of orthodontics.

CONCLUSION

For Co-Gn and Co-Go, the average linear increase with an increase in maturation stages is observed and is evidenced for a longer duration in males than females. For Co-Gn, it is evidenced in class I than class II, and for Co-Go it is evidenced higher in class II than class I. The greatest peak is observed at a definite interval between CVS 2-3 and CVS 3-4 in both skeletal malocclusion and genders. So, it can be concluded that if the functional or dentofacial orthopedic treatment modality is applied during CVS 2-3 or just before the onset of stage CVS 3-4 can result in normal mandibular length and orientation.

Ethical clearance

Study was conducted after getting clearance for ethical committee (Ethical Clearance/Awadh Dental college and Hospital/5/8/2019).

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.