Objective: To evaluate the ponticulus posticus according to the skeletal relationship found in strict lateral radiographs at the Centro Dental Docente of the Universidad Peruana Cayetano Heredia during the period 2015–2017, using the classification according to the degree of mineralization described by Selby and Steiner’s skeletal relationship classification. Material and methods: It was performed on digital strict lateral radiographs using a 20-inch screen using the SIDEXIS XG program, observing the degree of mineralization of the ponticulus posticus: without evidence of the bony spicule over the vertebral artery = absent bridge, when spicule formation and/or calcification was noted or evident in the middle of the bridge or incompletely = partial bridge, when the bony arch was evident finished visualizing = complete bridge and the classification of the skeletal relationship by measuring the ANB angle: Class I = 0–4°; Class II = >4° and Class III = <0°: the statistical analysis was done with the SPSS V program.22.0 for Windows using the Chi-square tests. Results: Of the 925 digital strict lateral radiographs evaluated, 283 radiographs were found to present ponticulus posticus and the highest frequency was found in the absent type (69.4%), the partial type (17.1%) and the complete type (13.5%). The ponticulus posticus was present in 25.1% of the female and 38.4% of the male. The skeletal relationship associated with ponticulus posticus was present in Class II (19.1%), Class I (10.4%) and Class III (1.1%). Conclusions: The ponticulus posticus is an anatomical variant present in 30.6% of cases. No statistically significant difference was found between the presence of ponticulus posticus and skeletal relationship or sex.

Objective: To determine the presence of bacteria by means of microbiological analysis on the surfaces contacted by the operator during the taking and processing of intraoral radiographs at different times of the day in the Oral Radiology Service of the UPCH. Materials and methods: Nine surfaces of the oral radiology service were sampled. The samples were taken at two times by the same investigator; at the beginning and the end of the activities in the service, the surfaces were swabbed with Trypticase Soy Broth (TSB). The samples were inoculated and incubated in three culture media (Plate Count Agar, Lamb’s Blood Agar and Cetrimide Agar). Then the respective Colony Forming Unit (CFU) count was performed and Gram staining was also performed. Results: A high concentration of bacteria (4180 CFU/mL) and fungi was found in the oral radiology service. Gram-positive cocci were the most frequently found microorganisms and gram-negative bacilli were less frequently found. Conclusions: There is a high contamination of bacteria in the oral radiology service. When the activities are completed, the number of bacteria decreases, but the variety of bacteria increases.