Aim: The aim of this study was to detect the prevalence of first permanent molar loss in a population of Saudi adolescents and young adults in the Kingdom of Saudi Arabia and to investigate the reasons behind such loss.

Materials and Methods: 252 Saudi patients aged (13-20) years who live in the Kingdom of Saudi Arabia were randomly selected and equally divided into two age groups: (13-16) years (17-20) years for the purpose of achieving comprehensive distribution. The study was carried out in the period February through April 2018. The patients were clinically examined for extracted or diagnosed for extraction first upper and lower permanent molars. In addition to clinical examination, panoramic radiographs were also used. The reason for extraction was documented whether by asking the patients why their tooth was extracted or by dental examination for the tooth diagnosed for extraction. The data obtained were documented in a patient examination form then statistically analyzed using Chi-Square Test.

Results: The prevalence of first permanent molar loss was detected to be (31.3%). A total of 79 patients (31.3%) presented with at least one first permanent molar loss

(p=0.000<0.05). The total number of missing first permanent molars was (n=117 teeth), and there were more observations of first lower permanent molar loss (n=85 teeth) (72.6 %) than first upper permanent molar loss (n=32 teeth) (27.4%) (p=0.000< 0.05). Caries was the dominant reason for tooth loss.

Conclusion: Early childhood preventive and dental education programs need to be implemented targeting caries and first permanent molars.

Keywords: First permanent molar loss, upper/maxillary, lower/mandibular, caries.