Rom J Morphol Embryol 2011, 52(4):1343–1346 R J M E RIGINAL APER Romanian Journal of O P Morphology & Embryology http://www.rjme.ro/

Cephalometric investigation of Class III dentoalveolar malocclusion

CAMELIA SZUHANEK1), E. GÂDEA PARASCHIVESCU2), ALINA MARIA ŞIŞU3), A. MOTOC3)

1)Discipline of Pedodontics and Orthodontics 2)Discipline of Maxillofacial Surgery 2nd Department of Dental Medicine 3)Department of Anatomy and Embryology “Victor Babeş” University of Medicine and Pharmacy, Timisoara

Abstract The aim of our study was to identify the most important anatomical landmarks in the cephalometric evaluation of Class III patients and to clarify the morphological characteristics of these cases. A group of 10 Class III orthodontic patients was evaluated in this study. The control group consisted of 10 patients with average occlusion and skeletal characteristics. Digital lateral cephalometric X-rays were performed and different measurements were analyzed. Cephalometric data were evaluated with the CephX specialized software for orthodontic diagnosis and the results were statistically analyzed. The Class III group presented specific characteristics such as prognathic mandible, large gonial angle, short maxillary length, higher lower facial height. These findings can be useful for the diagnosis and treatment planning of orthodontic cases with dental/skeletal anomalies, especially in cases when surgical approach is considered. The surgical decision must be taken after an accurate investigation of the lateral cephalometric parameters. Keywords: cephalometric analysis, Class III malocclusion, orthodontics, diagnosis, treatment planning.

 Introduction 6. Pogonion (Pg): the most anterior point on the symphysis of the mandible. Lateral cephalometric is the gold standard in 7. Sella (S): a constructed point in the middle of the assessing hard and soft tissue cranial profiles, using a sella turcica. list of standard landmarks. Orthodontists have relied on radiographic cephalometry, as it has been one of the Soft tissue landmarks most important diagnostic tools [1, 2]. Also, lateral and The aim of our study was to identify the most antero-posterior cephalograms have been important for important anatomical landmarks in the cephalometric surgical orthodontic corrections of jaw discrepancies. evaluation of Class III patients and to clarify the Cephalometric techniques can be used in order to morphological characteristics of these cases. predict the result of orthodontic treatment combined 1. Naso-labial angle: the angle formed by the labial with surgery. surface of the upper lip at the midline and the inferior The following are some of the most important border of the nose. It is a measure of the relative cephalometric landmarks that were used in the protrusion of the upper lip. cephalometric analysis [1–3]. 2. Soft tissue line-upper lip. 3. Soft tissue line-lower lip. Skeletal landmarks Dental landmarks 1. A-point (A): an arbitrary point at the innermost curvature from the anterior nasal spine at the crest of the 1. Interincisal angle; maxillary alveolar process. 2. Lower incisor position; 2. B-point (B): an arbitrary point on the anterior 3. Lower incisor inclination; profile curvature from the mandibular landmark, 4. Lower incisor protrusion; pogonion, to the crest of the alveolar process. 5. Upper incisor inclination; 3. Gnathion (Gn): the most downward and forward 6. Upper incisor protrusion. point on the profile curvature of the symphysis of the mandible.  Patients and Methods 4. Gonion (Go): the most posterior and inferior point on the angle of the mandible that is formed by the A group of 10 Class III orthodontic patients was junction of the ramus and the body of the mandible. evaluated in this study. The control group consisted 5. Nasion (N): the most anterior point of the frontal of 10 patients with average occlusion and skeletal suture. characteristics. Digital lateral cephalometric X-rays were

1344 Camelia Szuhanek et al. performed and different measurements were analyzed.  Results Cephalometric data were evaluated with the CephX The digital lateral cephalograms from both groups specialized software [5] for orthodontic diagnosis and were analyzed with the CephX orthodontic software in the results were statistically analyzed. order to obtain accurate data. Results are presented in the Tables 1–4. The typical Class III patient presented: ▪ Class III skeletal relationship (ANB = -6.94); ▪ Mandible forward to maxilla (concave profile); ▪ Mandible protruded; (a) (b) ▪ Upper incisor proclined forward; Figure 1– (a) Normal occlusion, frontal view. (b) ▪ Lower incisor too upright; Class III malocclusion, frontal view. ▪ Upper lip retruded; ▪ Lower lip protruded; ▪ Concave profile. No differences related to the skeletal, dental and soft tissue variables were found related to the gender of evaluated patients.

Figure 2 – Initial panoramic radiographic examina- tion.

Figure 4 – CephX image overlay of the soft tissue profile to the cephalometric X-ray.

(a)

Figure 5 – DiPaulo analysis of a Class III patient (CephX) horizontal discrepancy between jaws – 20 mm. (b) Figure 3 – (a) Lateral cephalogram of a Class I Table 1 – Burlington Woodside analysis patient. (b) Lateral cephalogram of a Class III Control Class III Parameter Type SD patient. group group Mandible length mm 114 5.0 115.07 The panoramic radiography (OPG) gives an excellent Maxillary length mm 114 5.0 83.06 view of the dental and skeletal structures extending Mdb-Mx difference mm 32.01 from the left to the right mandibular condyle, showing Lower face height ANS–GN 55.0 3.0 52.97 also all existing treatments/problems regarding teeth Upper face height mm 47.55 [6, 7]. The lateral cephalogram shows clearly all dental Total face height mm 101.11 and skeletal elements of the craniofacial structures SD – Standard deviation; Mdb – mandible; Mx – maxillary; ANS–GN including soft tissue profile (Figure 4). – anterior nasal spine-gnathion.

Cephalometric investigation of Class III dentoalveolar malocclusion 1345 The cephalometric prediction suggested that surgical Table 4 – Dental analysis in the two groups taken movement would optimize the dental and facial balance into this study

0 Control Class III (Figure 6). Parameter [ ] SD group group Interincisal angle 135 124–150 138.69 Lower incisor inclination 92 84–99 81.33 Lower incisor position 4 0–8 2.22 Lower incisor protrusion 2 -1–+6 6.23 Upper incisor inclination 103 92–114 114.39 Upper incisors protrusion 5 1–7 1.33 SD – Standard deviation.

 Discussion The prevalence of Class III varies widely among races and populations. Historically, the Class III malocclusion with retrognathic maxilla was described as Figure 6 – Cephalometric objectives of the ortho- the “Habsburg jaw” as its prevalence in this royal gnathic treatment obtained with CephX software in a family was high. A recent study [8], evaluated the Class III patient. dentoskeletal features of the “Habsburg jaw” by analyzing the skull of Joanna of Austria. The cephalometric values of Joanna were compared to standards for adult female subjects by Lippi D et al. The cephalometric analysis revealed the presence of a skeletal Class III associated with maxillary retrusion. The mandible presented with increased dimensions both in total mandibular length (Co–Gn) and in the mandibular body (Go–Gn). Our study evaluated the cephalometric characteristics of Class III in a group of Romanian patients. When compared with the control group, the Class III group presented specific bone characteristics such as prognathic mandible, large gonial angle, short maxillary length, wide saddle angle, increased lower facial height. The upper lip was frequently retruded, as the lower lip was protruded. The lower incisors were frequently proclined Figure 7 – Ricketts analysis and values in a Class III forward. The chin was frequently protruded. These patient. findings can be useful for the diagnosis and treatment planning of orthodontic cases with dental/skeletal Table 2 – Skeletal analysis in the two groups taken anomalies, especially in cases when surgical approach is into this study considered. Parameter Control Class III 0 Measurement SD When compared to a previous study that evaluated [degrees ] group group the Japanese norms [9], our Caucasian Class III group Palatal plane to ANS–PNS to mandibular mandibular 28 25–33 16.16 presented a slight more retrognathic maxilla and plane plane decreased values of incisor inclination. Previous studies Y-axis vertical/ SGN/FH 59.4 53–66 48.36 have evaluated the cephalometric norms in different horizontal growth populations and races [10–15]. Studies have shown that Maxilla to cranium SNA 82 75–85 78 the frequency of Class III is higher in Asia and Middle Mandible to cranium SNB 80 73–85 85 East than in European populations. The Middle East Maxilla to mandible ANB 2 0–3 -6 patients have a lower upper facial height comparing Wits 0 0–4 -8.3 to the Asian and Caucasian groups. No significant SD – Standard deviation; ANS–PNS – anterior nasal spine–posterior nasal spine; SGN/FH – Sellae-Gnathion to Frankfurt Plane; SNA, differences were found between the antero-posterior SNB, ANB – were taken from Steiner analysis that determines the position of the mandible between the Asian and angles between maxilla/mandible and cranium base. Caucasian populations. Table 3 – Soft facial profile analysis in the two The treatment of the Class III malocclusion should groups taken into this study be established after an accurate diagnosis [16, 17].

0 Control Class III Therapeutical methods are varied according to the Parameter [ ] SD group group patient age and the problem severity. Camouflage Naso-labial angle 100 90–110 84.81 treatment can be obtained in some less severe cases, but Soft tissue line–upper lip -2 -4–+1 -7.54 with special attention to the periodontal status of these Soft tissue line–lower lip -2 -4–+1 -2.36 patients [18]. After the growth completion, in severe SD – Standard deviation. cases, the surgical/orthodontic approach can be

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Corresponding author Camelia Szuhanek, Assistant Professor, MD, PhD, Discipline of Pedodontics and Orthodontics, 2nd Department of Dental Medicine, “Victor Babeş” University of Medicine and Pharmacy, 2 Eftimie Murgu Square, 300041 Timişoara, Romania; Phone +40724–251 240, e-mail: [email protected]

Received: September 5th, 2011

Accepted: December 5th, 2011