Some resin polymers available for three-dimensional (3D) printing are slightly elastic, which may be advantageous when used for full crown coverage of the primary teeth. This study was performed to evaluate the mechanical properties of two types of 3D-printed resin crowns in terms of strength and surface characteristics. Polymer resins used for temporary crowns (TCs) and temporary flexible dentures (TFDs) were tested. Digitally designed crowns with different thicknesses (0.4 and 0.6 mm) were 3D-printed. Milled zirconia crowns were used as the control. The static and dynamic fracture loads of the crowns were measured. The crown surface was evaluated using scanning electron microscopy. The average strength did not differ between the types of crowns. The differences between the dynamic and static fracture loads were insignificant. In the TC group, thicker crowns showed lower strength both under static and dynamic loads. After thermomechanical loading, microcracks and dropouts of macrofillers were detected on the surface of all types of resin crowns. The deposition of abraded debris occurred more in the TFD group. The 3D-printed resin crowns were thought to endure biting forces in children. However, some limitations of the material itself should be improved for consideration as a new treatment option in pediatric dentistry.

Autotransplantation is a potential treatment alternative when orthodontic traction of an impacted tooth is difficult. In this article, we describe two cases of guided autotransplantation of an impacted canine using a computer-aided designed and manufactured surgical template. The impacted canine was segmented on preoperative cone-beam computed tomography images to ensure a sufficient periodontal ligament space and placement of the donor tooth with the least pressure on it. The canine was virtually transposed using a simulation program considering the adjacent teeth. The surgical template, which was connected to the occlusal stop on adjacent teeth, was designed and 3D-printed with polymer resin. The recipient site was prepared using the surgical template, followed by immediate transplantation of the surgically extracted canine into the socket. The transplanted donor tooth was positioned in planned infra-occlusion to prevent occlusal interference. It was then splinted with the adjacent teeth for initial stabilization. During follow-up, one transplanted tooth showed pulp canal obliteration and the other had suspected pulp necrosis; endodontic treatment was performed. One year after the procedure, the periradicular condition of both teeth was favorable.

Eun Jin Seo, Soyoung Park, Eungyung Lee, Yang Hoon Huh, Ye Eun Ha, Gabor J. Tigyi, Taesung Jeong, Il Ho Jang, Jonghyun Shin. IJSC 2024;17:330-6. https://doi.org/10.15283/ijsc23105

The purpose of this study was to investigate the prevalence and patterns of congenitally missing teeth in permanent teeth excluding third molars, in patients aged 8 to 16 years who visited Pusan National University Dental Hospital from January 2010 to February 2021. This retrospective study evaluated tooth agenesis and the pattern of missing teeth represented by the tooth agenesis code by reviewing panoramic radiographs and electronic medical records of 11,759 patients, including 5,548 females and 6,211 males. The prevalence of congenitally missing teeth was 10.74% (females 11.95%, males 9.66%, p < 0.0001). Patients with tooth agenesis had an average of 2.22 missing teeth, and congenitally missing teeth occurred more frequently in the mandible (8.39%) than in the maxilla (4.52%, p < 0.0001). The mandibular second premolar (58.19%) was the most frequently missing tooth. The second premolar was the most frequently missing tooth in all quadrants (30.10%, 31.67%, 43.14%, and 35.59%) when a single tooth was absent, while the first and second premolars were the most commonly absent teeth (11.69%, 11.47%, 5.94%, and 5.24%) when two or more teeth were missing. In the relationship between maxillarymandibular antagonistic quadrants and full mouth, the 1st to 4th place of the missing patterns were all involved with the 1st and 2nd premolars. This study can be clinically helpful in establishing a treatment plan for patients with missing teeth. In addition, it can be used as basic data for molecular biological research to find out the relationship between tooth agenesis and specific genes.

When planning dental treatment for patients with rare diseases, a comprehensive evaluation of the patient's systemic condition, including oral examination, general growth, developmental stage, and medical history, is required. If the disease itself causes orofacial complications, it is essential for dentists to understand the disease and actively implement preoperative treatment to prevent complications such as infection and bleeding in collaboration with the primary physician. In addition, for patients who have difficulty with oral care due to a decline in intellectual ability and physical function, the role of the guardian and caregiver is important, and it is necessary to create a dental home environment. Patients with low compliance levels may consider dental treatment under general anesthesia and should receive continuous oral care, including dental adaptation training. Ultimately, it is essential to instruct patients and their guardians so that they can take care of their own oral health as they grow.

The purpose of this study was to analyze the accessibility to dental facilities and the differences in chief complaints of new patients who visited Pusan National University Dental Hospital. We collected information from electronic medical records for 1,820 new patients. The accessibility was analyzed by measuring the distance from the patient’s house to the dental facilities. The distance was categorized into 10 km sections, and the presence or absence of a local pediatric dental clinic within 10 km of the patient’s house was also categorized. As the distance between the house and Pusan National University Dental Hospital increased, the proportion of patients who visited for dental caries decreased, and orthodontic treatment increased. Dental caries accounts for 27.9% of less than 10 km and 20.5% over 30 km. Orthodontic treatment accounts for 25.4% within 10 km and 27.3% more than 30 km away. The presence or absence of a local pediatric dental clinic within 10 km did not significantly affect the distribution of chief complaints. This study can be used as basic research data to establish effective treatment measures that can improve the physical and geographical accessibility of patients visiting pediatric dentistry.