Research Article Assessment of ramus notch depth in different skeletal malocclusion B. Priya, Saravana Pandian* ABSTRACT Introduction: Mandibles which demonstrate backward and downward rotation during growth have been found to experience apposition beneath the gonial angle together with excessive resorption under the symphysis. Subjects with deep antegonial and ramal notching were reported to have disturbed condylar growth and have shown that the mandibular growth potential is diminished in subjects with pronounced antegonial and ramal notching. Aim: The aim of this study was to assess ramus notch depth (RN) in relationship with skeletal Class I, Class II, and Class III. Materials and Methods: The sample consisted of 60 pretreatment digital lateral cephalometric radiographs having skeletal Class I, Class II, and Class III pattern and aged between 14 and 35 years. Results: There were no significant differences in the ramal notch depth between skeletal Class I, Class II, and Class III. Conclusions: The RN is not affected by sagittal jaws relationship. The increased RN may be one of the signs of the long face syndrome without open bite. Deep ramus notch is associated with the mandibular retrusion or backward position of the ramus. KEY WORDS: Class I, Class II, Class III lateral cephalogram, Ramus notch depth, Skeletal patterns INTRODUCTION alveolar border, wider behind than in front, is hollowed into cavities in the regions where the teeth are found; The lower jaw bone , known as the mandible is the these cavities are sixteen in number and vary in depth largest, strongest and the most inferior bone in the and size according to the teeth which they contain. To [1] human face. It forms the lower jaw and holds the the outer surface of the superior border, on either side, lower teeth in place. The mandible is placed beneath the buccinator is attached as far forward as the first the maxilla. The mandible is the only movable bone molar tooth. of the skull beside the ossicles of the middle ear. Mandible is the only movable bone in the facial The superior border is shorter than the inferior- skeleton. The left and right processes together fused superior and thicker in front than behind; a shallow to form bone, and the point where these sides join, the groove exists on the lower border of the ramus which mandibular symphysis, is still visible as a faint ridge houses the facial artery. in the midline.[2] Rami The mandible consists of body and two rami. The body The ramus of the human mandible has four sides, found at the front and a ramus on the left and the right; two surfaces, four borders, and two processes. The the rami rise up from the body and meet with the body ramus of the mandible consists of two surfaces at the angle of the mandible. (lateral and medial) and four borders (anterior, posterior, inferior, and superior). Lateral surface Body gives insertion of the masseter muscle, and medial The mandible resembled like a horseshoe and has two surface presents (a) mandibular foramen, (b) lingual, surfaces and two borders. Borders are, the superior or (c) mylohyoid grooves, and (d) insertion of medial pterygoid muscle. Anterior border of mandible Access this article online receives the insertion of the temporalis muscle. The posterior border of the ramus is related to the parotid Website: jprsolutions.info ISSN: 0975-7619 gland. Department of Orthodontics and Dentofacial Orthopedics, Saveetha Dental College and Hospitals, Saveetha University, Chennai, Tamil Nadu, India *Corresponding author: Saravana Pandian, Department of Orthodontics and Dentofacial Orthopedics, Saveetha Dental College and Hospitals, Saveetha University, Chennai – 600 077, Tamil Nadu, India. Phone: +91-9003101627. E-mail: [email protected] Received on: 17-08-2018; Revised on: 22-09-2018; Accepted on: 29-10-2018 480 Drug Invention Today | Vol 12 • Issue 3 • 2019 B. Priya and Saravana Pandian Borders connective tissues receiving local input control signals The lower border of the ramus is thick, straight, producing progressive compensatory changes in the [5] and continuous with the inferior border of the body shape and size of the ramus. of the bone. The anterior border of ramus is thinner The efficacy and timing of the treatment of superiorly while thicker inferiorly and is continuous malocclusions often depend on the pubertal growth with the oblique line. spurt.[6,7] Treatment effects may be impaired or The region where the lower border meets the posterior enhanced by variations in the direction, timing, and [8-10] border is the angle of the mandible, often called the duration of development in facial area; thus, gonial angle. extensive knowledge of facial morphology and development is necessary for the successful treatment The posterior border of the ramus is thick, smooth, of dentofacial deformities. Directional growth rounded, and covered by the parotid gland. The upper has assumed greater relevance with the increased border is thin and is surmounted by two processes, the realization that considerable individual variation coronoid in front and the condyloid behind, separated occurs in craniofacial growth and morphology.[11] by a deep concavity, the mandibular notch. Subjects with deep antegonial and ramal notching were reported to have disturbed condylar growth,[12-16] Processes Other studies[16,17] have shown that the mandibular The coronoid process is flattened from side to side growth potential is diminished in subjects with and varies in shape and size which is thin, triangular pronounced antegonial and ramal notching. eminence. The aim of this study was to investigate ramus notch The condyloid process is thicker than the coronoid depth (RN) in relation to the skeletal Class I, Class II, and consists of two portions: The condyle and the and Class III malocclusion. constricted portion which supports it, the neck. MATERIALS AND METHODS The lower borders meet the posterior border at the angle of the mandible, and the angle is incurved in The sample included 60 digital lateral cephalometric females but prominently everted in males. The males radiographs which were collected in the Orthodontic have squarer, stronger, and larger mandibles than Department at the Saveetha Dental College and Hospital females. The mental protuberance is more pronounced which are further elaborated in Table 1. The 60 subjects in males but can be visualized and palpated in females. included in the study comprised of 27 females and 30 males, their age ranged between 18 and 31 years. In orthodontics, skeletal growth is emphasized more The sample was divided according to the sagittal jaw than other aspects of craniofacial development, perhaps, relationship using ANB angle[18,19] into: Skeletal Class I because the methods for its study were developed (2° ≤ ANB ≤4°), Class II (ANB >4°), and Class III (ANB earlier. Knowledge of skeletal morphology and growth <2°). They were clinically healthy with no craniofacial is routinely applied in clinical practice; these can be syndromes or anomalies, such as a cleft lip and palate. visualized easily in the cephalogram. Craniofacial Subjects were excluded if they had a history facial skeletal growth is very important in orthodontics, since trauma or previous orthodontic, orthopedic, or surgical variations in craniofacial morphology are the source of treatment. All the cephalograms were taken with the most serious malocclusions, and induction of changes subject’s teeth in intercuspal position and traced by the in intermaxillary relationships is fundamental to same researcher [Figures 1-3]. The radiographs were orthodontic treatment.[3] Any alteration or adjustment analyzed using the FACAD software computer program of one part of the dentofacial complex will require a to calculate the linear measurement. After importing the like adjustment by another part of the complex for its picture to the FACAD program, points and planes were own accommodation and so on.[4] determined, and then, the linear measurements were obtained. Linear measurements, however, were divided The ramus of the mandible is the providing attachment by a scale for each picture to adjust for magnification. for masticatory muscles. However, the ramus is The scale was obtained depending on the measurement also integral to place the corpus and dental arch into from the ruler in the nasal rod. harmonious relationship with the maxilla and other [20] facial structures. Correct relationships are maintained by Cephalometric landmarks critical remodeling and adjustments in ramus alignment, The following cephalometric landmarks were used in vertical length, and anteroposterior dimensions. Indeed, this study [Figure 1]: the special developmental significance of the ramus is 1. Gonion (Go): A constructed point, the intersection integral to craniofacial growth. These alterations are of the lines tangent to the posterior margin of the induced by osteogenic, chondrogenic, and fibrogenic ascending ramus and the mandibular base. Drug Invention Today | Vol 12 • Issue 3 • 2019 481 B. Priya and Saravana Pandian Linear measurements[16] 1. RN:The distance along a perpendicular line from the deepest point of the RNC to a line connecting point Articulare with the point of greatest convexity on the posterior border of the angular process of the mandible.[17] 2. Ramus length: From Ar to Go 3. Mandibular body length: From go to me Statistical analysis The data were subjected to computerized statistical analysis using SPSS. The statistical analyses included descriptive statistics with mean values, standard deviation, minimum, and maximum values for continuous measurements. Statistics include the Figure 1: Class I skeletal pattern ANOVA to compare the skeletal classes. The following levels of significance were used: • Non-significant - NS P > 0.05 • Significant - 0.05 ≥ P > 0.01 • Highly significant - 0.01 ≥ P > 0.001 • Very highly significant - P ≤ 0.001. ANOVA test was used to compare the mean values of the RN between the skeletal Class I, Class II, and Class III. RESULTS The descriptive statistics for each skeletal class were presented from which we can distinguish that all were no-significantly difference in the RN in skeletal Class I, Class II, and Class III.