Non-syndromic occurrence of true generalized microdontia with hypodontia: A case report

RATIONAL: Dental abnormalities can occur at any stage of tooth development. Of these abnormalities, true generalized microdontia is a rare condition in which all teeth are smaller than normal, while hypodontia is defined as the absence of 1 to 5 teeth. As far as we are aware, no article has reported a case of the non-syndromic occurrence of true generalized microdontia with hypodontia. PATIENT CONCERNS: A 9-year-old girl who had no systemic diseases presented with congenital absence of maxillary lateral incisors bilaterally and small teeth involving the whole dentition. DIAGNOSES: Based on intraoral examinations and panoramic radiograph, the patient was diagnosed with the simultaneous occurrence of true generalized microdontia, hypodontia, and a variation of maxillary 1st molar with a single root and single canal. Also, the patient had premature loss of mandibular molars and canines, periapical periodontitis in the mandible left 1st primary molar and deep caries in mandible left secondary primary molar. INTERVENTIONS: A removable appliance to hold space for early loss of mandibular molars and canines was made at the present stage. The mandible left 1st primary molar had periapical periodontitis and the affected tooth was extracted. Furthermore, the distal surface of the mandible left 2nd primary molar was filled with complex resin materials. A multi-disciplinary therapy plan was carefully designed including orthodontics, dental implants and esthetic restoration in the future. OUTCOMES: The patient complied well with instructions for wearing the removable space maintainer, which helps prevent mesial migration of the permanent 1st molars, at the current stage. The therapeutic efficiency on periapical periodontitis and caries lesions was also good. LESSONS: The non-syndromic presence of true generalized microdontia is extremely rare. A personalized treatment plan with multi-disciplinary considerations should be given for these patients. The pathogenesis remains unclear but may be related to genetic as well as environmental factors. More studies are urgently needed to explore the pathogenesis and treatment options for the future.