ORIGINAL�ARTICLE ABSTRACT Objective: To determine the prevalence and association of Ponticulus Posticus with dental and skeletal malocclusions in our local population. Study Design: Cross sectional, observational study Place and Duration of Study: Orthodontics department of a tertiary care hospital based in Islamabad using st st records between the duration of 1 March, 2014 – 31 February 2018. Materials and Methods: The study was conducted using lateral cephalograms of the patients visiting the Orthodontic department which were analysed against age, gender, skeletal and dental malocclusions of the patients obtained from the patient records. For the incidence of Ponticulus Posticus a total of 1194 radiographs were obtained using convenience sampling and analysed using SPSS version 17 and Pearson's Chi-Square test was applied. Results: A combined frequency of PP was found to be 18.1% (181/817). A higher frequency in males 22.6% (77/264) as compared to females 15.8% (104/553) exhibited a significant difference (p < 0.05). Partial type of Ponticulus Posticus was more frequent (61.3%) as compared to Full (38.7%). Partial variant expressed a higher frequency in skeletal (49.5%) and dental (48%) class II malocclusion. Whereas, the full variant of Ponticulus Posticus exhibited a higher frequency in Dental Class II (48.6%) and skeletal Class I (55.7%) respectively. Conclusion: Our data suggests that frequency of Ponticulus Posticus in our local population shows male preponderance in dental class II malocclusion, however, no significance was established in relation to its association with skeletal or dental malocclusions. Key Words: Arcuate Foramen, Atlas, Dental and Skeletal Malocclusion, Kimmerle Anomaly , Ponticulus Posticus. articular process and posterolateral portion of 3 superior margin of the posterior arch of Atlas. This anatomical anomaly has been termed in the literature using various terminologies such as Arcuate Foramen, Kimmerle anomaly, Foramen 4,5 Atlantoideum being a few of them. Origin of PP with 6 clinical implications is not yet fully understood and subjected to ongoing research with endochondral origin from the dorsal arch of atlas proposed in the 7 literature. 3 PP has prevalence ranging from 1.3% - 60% with 8 ethnic variation. There is a lack of data on the Asian 9 population, no such study is yet reportedly conducted in Pakistan. Recent meta-analysis shows preponderance in female gender (18.5%) as 8 compared to males (16.7%). The analysis is c o m m o n l y d o n e u s i n g va r i o u s a s s e s s i n g / 2 investigating tools such as CBCT, dried specimens of 10,11 C1 (Atlas) and most commonly employed method 12-14 comprising lateral cephalograms. Using these investigative techniques, the establishment of presence of PP and types can be assessed which can Introduction Ponticulus Positicus (PP) is a morphological variation of the ATLAS/C1 (the first cervical vertebra), famous for anatomical disparity leading to various clinical manifestations such as; migraine, neck pain, hearing loss and most importantly, incorrect assessment during orthopaedic surgery for atlanto-axial fixation 1 causing vertebral artery damage. Ponticulus posticus is a Latin word meaning “LITTLE POSTERIOR 1,2 BRIDGE”. It is a membranous ossification found between the posterior portion of the superior Prevalence of Ponticulus Posticus in Orthodontic Patients of the Local Population of Islamabad, Pakistan Qurat Ul Ain, Saqlain Bin Syed Gilani, Muhammad Aamir Ghafoor Choudry, Bakhtawar Yaqoob Awan Correspondence: Dr. Saqlain Bin Syed Gilani Assistant Professor Department of Dentistry Islamic International Dental College Riphah International University, Islamabad E-mail: saqlain.syed@riphah.edu.pk Department of Dentistry Islamic International Dental College Riphah International University, Islamabad Funding Source: NIL; Conflict of Interest: NIL Received: October 23, 2018; Revised: August 20, 2019 Accepted: August 27, 2019 Prevalence of Ponticulus Posticus in Orthodontic PatientsJIIMC 2019 Vol. 14, No.3 142 15-19 be Partial (incomplete) and Full (complete). Skeletal deformities, head, neck, cervical posture and morphological deviation along with variable orthopaedic findings are believed to have an 20,21 association with malocclusion. Studies have also reported a relationship between mandibular 22 positioning and cervical vertebral morphology. D'Attilio et al presented a statistically significant correlation between mandibular plane angle, position, length and overjet to the cervical 23 curvature. All these studies showing an association of orthopaedic findings with certain orthodontic findings led us to investigate the prevalence and association of Ponticulus Posticus with dental and skeletal malocclusions in our local population. Materials and Methods A cross-sectional study was undertaken at the Islamic Interational Dental Hospital, using the records from the archives of the Orthodontics department of patients who had undergone orthodontic treatment/consultation during a period of March 01, 2014 – February 31, 2018. A total of 1194 lateral cephalograms were acquired using non- probability convenience sampling. The ethical approval was obtained from the Institutional Ethical Review Committee. A total of 196 radiographs were excluded, the exclusion criteria comprised of poor visualization of posterior arch of atlas and patients with congenital facial abnormalities and/or syndromes. Radiographs were recorded using ART PLUS Dental X-Ray - FIN-02150 and examined by direct visualization under adequate illumination for the presence of the anomaly, and if present whether complete or partial. Gender, age, dental and skeletal malocclusions were noted. Radiographs were examined by two observers twice on different occasions to reduce intra operative error. In case of a disagreement, a third observer from the radiology department was consulted. The observers followed the classification by Miki et al which radiographically classifies the Ponticulus 24 posticus into three types: “Full type: it forms a complete bony ring. Incomplete type: some portions of the bony ring are defective. Calcified type: there is a linear or amorphous calcification.” Due to many intermediate forms of partial (PP) which may range from a spicule to some being ossified but not completely encircling the posterior arch, the variations were dichotomized to Complete and Partial for this study. All data was entered and subjected to statistical analysis using SPSS version 17. Using Pearson's Chi- square test, data was analysed to establish any association between occurrence, gender, age and malocclusions (skeletal & dental). Results The mean age of the subjects was 17.76 ± 5.41 years (range 7 – 51 years) and catogarized into three groups, Group I (7-14 years), Group II (15-20 years) & Group III (21 and above). Highest prevalence of PP was found in Group II, Partial form of PP was 44.1% and full form of PP was 37.1%. Total number of PP detected were 181 with a prevalence of 18.1% out of 998 radiographs (Partial: 61.3%, Full: 38.7%). Male patients showed a preponderance of PP n=77 (22.6%) as compared to females n=104 (15.8%) with significant difference (p<0.05) however, no significant difference (p>0.05) was observed between partial and full form of PP, age, skeletal & dental malocclusions. With the analysis of malocclusion groups, partial PP showed a relative predominance of dental 49 (48%) and skeletal 52 (49.5%) Class II malocclusions and conversely cases of complete/full PP showed a relative predominance of dental 32 (48.6%) Class II and skeletal 39 (55.7%) Class I malocclusion. However, there was no significant difference between different malocclusion groups (skeletal or dental) (p>0.05). Detail description available in Table I & II. Table I: Frequency of PP Based on Gender in Local Popula�on, P < 0.05 Table II: Frequency of PP Based on Dental and Skeletal Malocclusions, P > 0.05 JIIMC 2019 Vol. 14, No.3 143 Prevalence of Ponticulus Posticus in Orthodontic Patients Discussion T h e c r o s s - s e c t i o n a l s t u d y c o m p r i s e s o f cephalograms of the Orthodontically treated patients, as shown in figures 1(A) & (B), of our local population, the evaluation showed a prevalence of 18.1% with partial 61.3% & full 38.7%. The analysis of malocclusion groups showed a predominance of partial type PP in Dental Class II malocclusion and full type PP in Skeletal Class I. Different methods have been used to investigate PP, that entail plain radiography, CBCT, CT-scans and examination of dried specimens of Atlas. Various studies have been undertaken in different populations with highly variable results (1.3% – 60% prevalence), reported prevalences consist of a meta- analysis conducted by Przemyslaw A. et al which states that the least amount of cases of PP were reported in Asia as opposed to North America where 8 the frequency of PP was highest. Compared to our population, similar prevalences 25 were reported by Jae Taek Hong (15.6%), Young et 26 al, (15.5%). Kyeong Hwan Kim et al, Elliot & Tanweer 2 7 (16.6%) and Yong Jae (14%) and (15.5%) 4,28 29 respectively. However, V Sharma et al. (4.3%), 9 Chitrodka PK et al. (60%) showed contrasting results. A significant male predominance was observed in our local population (p < 0.05) which is in coherence with a study conducted by Adisen and 3 Misirlioglu. Though a female predominance was also reported in a study with no significant difference 9 established between the genders (p>0.05). Whereas, some studies also suggested that there is no significant difference in the prevalence of the PP 7,27 among the two genders. Adisen and Misirlioglu, in their attempt to study the relationship between mandibular position and cer vical vertebra morphology, no association could be established but it was recommended to investigate the presence of PP in different dentoskeletal patterns in future studies. Middle Anatolian population had a higher frequency of the anomaly (PP) detected in Angle class III patients (22.2 %). Although no significant difference was observed between malocclusion 3 groups (p > 0.05) which is in coherence with the 2 results of this study. According to Sevki et al 2017 in Turkish population PP was most frequently detected in class III patients (13.8%) followed by class II (12.2%) and class I patients (10.5%). Statistically significant differences between the different sagittal skeletal groups were observed (p = ˂ 0.05). In the Turkish population, highest frequency of PP was found in Angle class III patients. Both these findings are in accordance with the study conducted by Sonnesen et al 2007 which showed significant (p = <0.001) relationship with mandibular overjet and cervical column morphological deviations as 30 compared to the control group. Many studies have tried to find any association with age, but none has been able to do so, while some studies have gone as far as to negate any such 29 association. Some claim it to be congenital, citing cadaveric and radiologic studies that have shown its presence in fetuses and children, with some still in the cartilaginous stage yet to ossify which supports the study conducted by Geist whose findings oppose the theory of it being a degenerative phenomenon 18 which occurs as a result of aging. Some studies have shown that in some cases it is able to ossify over the 31 years while in others it remains in a spicule/partial form throughout life, which suggests no association of the bridging process with life. One of the limitations in the study design was that the lack of extensive Computated Tomography which could have revealed the frequency more accurately by determining if the anomaly was bilaterally present or unilaterally. The observers were not trained radiologists and a trained radiologist was only consulted in cases where both the observers opinions differed. Conclusion Our data suggests that frequency of Ponticulus Posticus in our local population shows male preponderance in dental class II malocclusion, however, no significance was established in relation to its association with skeletal or dental malocclusions. 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