|Year : 2013 | Volume
| Issue : 2 | Page : 76-79
Analysis of growth of prenatal mandible by different parameters
Anjali G Gosavi, Sarita R Margam
Department of Anatomy, Ashwini Rural Medical College, Hospital and Research Center, Kumbhari, Solapur, Maharashtra, India
|Date of Web Publication||23-Jul-2013|
Anjali G Gosavi
Department of Anatomy, Shri Ramkripa, Block no 33, Vikasnagar, Solapur - 413 003, Maharashtra
Source of Support: None, Conflict of Interest: None
Introduction & Objective: The purpose of this study was to compare different parameters of mandible and to correlate them with age of fetus in lunar months. Thus we can arrive at the age of fetus with reasonable approximation. Materials and Methods: Study consists of fetal hemimandibles both right and left sides. Fetal age ranges from 4 th to 7 th lunar month. Sixty-four hemimandibles (32 mandibles) were collected from fetuses after their maceration. The measurements were performed Condyle-Coronoid (Co-Cp), Gonion-Coronoid (Go-Cp), Gonion-Gnathion (Go-Gn), Condyle-Gnathion (Co-Gn), Symphyseal height (SH), and Mandibular angle (MA) processes. Data was analyzed with SPSS software program and 't' test was performed. Statistically highly signifi cant positive correlation was found between CR length and Co-Cp, Go-Cp, Go-Gn, Co-Gn, and SH and a negative correlation was found between CR length and MA of both sides. Correlation coefficient of right and left hemimandibles were nearly equal. The regression equation for CR length was estimated by SPSS software program. Results and Conclusion: It is possible to arrive at the CR length of fetus with the help of regression equation. From CR length, we can easily predict the age using these hemimandibles.
Keywords: Gonion, maceration, mandible, prenatal, regression
|How to cite this article:|
Gosavi AG, Margam SR. Analysis of growth of prenatal mandible by different parameters. J Sci Soc 2013;40:76-9
| Introduction|| |
Mandible appears in adults as a single bone of lower jaw. During development of mandible, it ossifies with different centers of ossification to form hemimandible.  Two hemimandibles are joined by symphysis menti, which ossifies to form a single mandible. Ossification of symphysis menti starts at 1 st year after birth and completes by 2 to 3 rd years after birth. 
Research on fetal mandibular growth basically correlates with the development of mandibular structures with fetal age.  The purpose of this study was to compare different parameters of mandible and to correlate them with age of fetus in lunar months. We can arrive at the age of fetus with reasonable approximation.
Research has emphasized that any structural change in mandibular cartilage during prenatal period is more intimately related to local mechanical factors and articulation than bone growth.  The functions exerted by masseter and temporalis muscle induce mandibular growth during 11 th week. 
| Materials and Methods|| |
Sixty-four hemimandibles (32 mandibles) of fetuses were studied in the present work. The fetuses were supplied by the Department of Obsetrics and Gynecology, Chatrapati Shivaji Sarvopachar Rugnalaya, Solapur.
Fetuses with no malformation were observed in this study. The study was preapproved by ethical committee of Dr. V. M. Medical College, Solapur.
Gestational age ranged from 4 th to 7 th lunar month, according to protocol and CR length measured before maceration.
After measuring CR length, fetuses were kept in running tap water for maceration. It took 4 to 8 months to remove soft tissue over bones. Periosteum was also removed for better visualization of anatomical landmarks.
Measurements were performed as follows [Figure 1]
Measurements were made one author only using sliding caliper. The extent of mandibular angle was measured with the aid of a protractor. The data was collected, tabulated, and analyzed with the aid of SPSS software and 't' test was performed to compare the mean values of anatomical measurements of right and left hemimandibles. Parameters were said to be significant if P value was < 0.05.
- Condyle-Coronoid Process (Co-CP): Distance between the posterior-most point on the condylar process and the anterior-most point on the coronoid process
- Gonion-Coronoid Process (Go-CP): Distance between the gonion and the upper-most point on the coronoid process
- Gonion-Gnathion (Go-Gn): Length from gonion to gnathion
- Condyle-Gnathion (Co-Gn): Distance between the posterior-most point on the condylar process and gnathion
- Symphyseal height (SH): Measured on the median area to be occupied by the future central incisors, corresponding to the vertical distance between the upper-most and lower-most portions of the mandibular symphysis
- Mandibular Angle (MA): Measured between the posterior margin of the mandibular ramus and the lower margin of the mandibular body.
| Results|| |
In [Table 1] shows statistically highly significant positive correlation between CR length and Co-Cp, Go-Cp, Go-Gn, Co-Gn, and SH and statistically significant negative correlation between CR length and MA of both sides. No statistically significant difference was observed between left and right sides of Co-Cp, Go-Cp, Go-Gn, Co-Gn, SH, and MA [Table 2].
Significant correlation was found between CR length and Co-Cp [Figure 2], Go-CP [Figure 3], Go-Gn [Figure 4], Co-Gn [Figure 5], SH [Figure 6], and MA [Figure 7] of both sides. Using these data, CR length can be predicted by regression analysis by taking CR length as dependent variable and other variables as independent variables.
|Figure 2: Correlation between CR length and Co-Cp of the left and right side|
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|Figure 3: Correlation between CR length and Go-Cp of the left and right side|
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|Figure 4: Correlation between CR length and Go-Gn of the left and right side|
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|Figure 5: Correlation between CR length and Co-Gn of the left and right side|
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|Figure 6: Correlation between CR length and SH of the left and right side|
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|Figure 7: Correlation between CR length and MA of the left and right side|
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The regression equation for CR length is estimated by SPSS statistical software, as follows:
CR length = 84−43.0 × Lt. Co-CP + 49.0 × Lt. Go-CP + 14.9 × Lt. Go-Gn + 58.9 × Lt. Co-Gn + 21.3 × Lt. SH −1.47 × Lt. MA + 28.6 × Rt. Co-CP −40.1 × Rt. Go-CP + 21.3 × Rt. Go-Gn −32.1 × Rt. Co-Gn −33.4 × Rt. SH + 1.26 × Rt. MA.
| Discussion|| |
In many conditions, either pathological or congenital mandibular measurements can vary and alter the mandibular dimentions. Mota et al., performed the same study on hemimandibles by dividing the lunar months into 3 periods. He observed that the mandibular body grows more rapidly than the ramus, both in length (Go-Gn) and height (SH), while symphysis height displays the highest growth rate. On the right side, higher growth rate were observed in Go-CP and SH, but all other measurements (Co-CP, Go-Gn, Co-Gn, MA) showed higher growth rates on the left side. 
In our study, we obtained positive correlation between CR length and Co-CP, Go-CP, Go-Gn, Co-Gn, and SH. All the values of correlation coefficient were statistically highly significant.
Malas et al.,  did a study of the mandibular angle in 162 fetuses, which showed that the mean values were 122 ± 8° with no significant differences between trimesters nor between left and right HMs. Mota et al.,  noted variation in the mean value of mandibular angle (143 ± 6) between 13 and 30 week per conception and increase early in 3 rd trimester, more pronounced on the left side.
In our study, we found statistically significant negative correlation between CR length and mandibular angle on both sides.
If we get a hemimandible only in medicolegal cases, it is possible to arrive at the age of fetus by CR length with the help of regression equation obtained by our study, which is as follows:
CR length = 84−43.0 × Lt. Co-CP + 49.0 × Lt. Go-CP + 14.9 × Lt. Go-Gn + 58.9 × Lt. Co-Gn + 21.3 × Lt. SH −1.47 × Lt. MA + 28.6 × Rt. Co-CP −40.1 × Rt. Go-CP + 21.3 × Rt. Go-Gn −32.1 × Rt. Co-Gn -33.4 × Rt. SH + 1.26 × Rt. MA.
| Conclusions|| |
The growth of different dimensions of fetal mandibles has correlation with increase in CR length. As CR length increases, all dimensions of mandible increases, except mandibular angle.
It is easy to estimate the age of fetus by measuring CR length of hemimandibles in medicolegal cases in case the rest of the skeletal remains is lost.
| References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
[Table 1], [Table 2]