Genotype and malocclusion in patients with osteogenesis imperfecta.

OBJECTS: To investigate the relationship between genotype and severity of malocclusion in osteogenesis imperfecta (OI). SETTING AND SAMPLE POPULATION: A total of 49 patients participated in this cross-sectional study (age range: 5-19 years; 28 females; diagnoses: OI type I, N = 7; OI type III, N = 11; OI type IV, N = 27; OI type V, N = 2; OI type VI, N = 2). MATERIALS AND METHODS: Sequence analysis of COL1A1/COL1A2 and other OI-related genes was compared to the Peer Assessment Rating (PAR), an index reflecting the severity of malocclusion. RESULTS: The mutation spectrum was as follows: COL1A1, N = 22; COL1A2, N = 22, IFITM5, N = 2; SERPINF1, N = 2; no mutation detected, N = 1). Compared to patients with COL1A1 mutations, patients with COL1A2 mutations had significantly higher scores for total PAR, anterior cross-bite, anterior open bite and anteroposterior buccal occlusion. Males with COL1A2 mutations had significantly higher total PAR scores than females (median 36 vs 30, P = .047, Mann-Whitney test). Exploratory correlation between age and buccal vertical occlusion was noted in patients with COL1A2 mutations (Spearman correlation: r = .46, P = .03, power = .50). Two patients with OI type V (caused by IFITM5 mutations) had total PAR scores of 44 and 21. Both patients scored high for "segment." Patients with OI type VI (due to SERPINF1 mutations) scored similar to OI type V for "centreline." Considerable difference was observed in the total PAR score between the 2 patients with OI type VI. They had total PAR of 43 and 2. CONCLUSION: Type of disease-causing mutation affects the severity of malocclusion in individuals with OI.

A standard set of outcome measures for the comprehensive assessment of oral health and occlusion in individuals with osteogenesis imperfecta.

BACKGROUND: Osteogenesis imperfecta (OI) is a group of inherited connective tissue disorders of varying severity characterized by bone fragility. The primary objective of this international multidisciplinary collaboration initiative was to reach a consensus for a standardized set of clinician and patient-reported outcome measures, as well as associated measuring instruments for dental care of individuals with OI, based on the aspects considered important by both experts and patients. This project is a subsequent to the Key4OI project initiated by the Care4BrittleBones foundation which aims to develop a standard set of outcome measures covering a large domain of factors affecting quality of life for people with OI. An international team of experts comprising orthodontists, pediatric dentists, oral and maxillofacial surgeons, and prosthetic dentists used a modified Delphi consensus process to select clinician-reported outcome measures (CROMs) and patient-reported outcome measures (PROMs) to evaluate oral health in individuals with OI. Important domains were identified through a literature review and by professional expertise (both CROMs and PROMs). In three focus groups of individuals with OI, important and relevant issues regarding dental health were identified. The input from the focus groups was used as the basis for the final set of outcome measures: the selected issues were attributed to relevant CROMs and, when appropriate, matched with validated questionnaires to establish the final PROMs which represented best the specific oral health-related concerns of individuals with OI. RESULTS: Consensus was reached on selected CROMs and PROMs for a standard set of outcome measures and measuring instruments of oral health in individuals with OI. CONCLUSIONS: Our project resulted in consensus statements for standardization oral health PROMs and CROMs in individuals with OI. This outcome set can improve the standard of care by incorporating recommendations of professionals involved in dental care of individuals with OI. Further, it can facilitate research and international research co-operation. In addition, the significant contribution of the focus groups highlights the relevance of dental and oral health-related problems of individuals with OI.

Craniofacial and Dental Defects in the Col1a1Jrt/+ Mouse Model of Osteogenesis Imperfecta.

Certain mutations in the COL1A1 and COL1A2 genes produce clinical symptoms of both osteogenesis imperfecta (OI) and Ehlers-Danlos syndrome (EDS) that include abnormal craniofacial growth, dental malocclusion, and dentinogenesis imperfecta. A mouse model (Col1a1(Jrt)/+) was recently developed that had a skeletal phenotype and other features consistent with moderate-to-severe OI and also with EDS. The craniofacial phenotype of 4- and 20-wk-old Col1a1(Jrt)/+ mice and wild-type littermates was assessed by micro-computed tomography (µCT) and morphometry. Teeth and the periodontal ligament compartment were analyzed by µCT, light microscopy/histomorphometry, and electron microscopy. Over time, at 20 wk, Col1a1(Jrt)/+ mice developed smaller heads, a shortened anterior cranial base, class III occlusion, and a mandibular side shift with shorter morphology in the masticatory region (maxilla and mandible). Col1a1(Jrt)/+ mice also had changes in the periodontal compartment and abnormalities in the dentin matrix and mineralization. These findings validate Col1a1(Jrt)/+ mice as a model for OI and EDS in humans.

Anterior Teeth Splinting After Orthodontic Treatment: 3D Analysis Using Finite Element Method.

OBJECTIVE: Retention after orthodontic treatment is still an important part of the treatment. Splints are considered as an alternative for removable retainers. The main goal of this study was to assess splinting biomechanically. MATERIALS AND METHODS: Three dimensional finite element models (3D) were designed of a mandibular anterior segment which included six anterior teeth with their supporting tissues (model 1 as control) and with a bonded lingual fixed retainer in the two other models. The wire cross section was round (0.016") in model 2 and rectangular (0.016" × 0.022") in model 3. The models were designed in Solid Works 2006 and analyzed in ANSYS Workbench Ver. 11.0 SolidWorks Incisors were loaded with a vertical force of 187 N. PDL stress and tooth displacements were evaluated. RESULTS: The numeric findings showed an increase after splinting in the central incisors [2.42 MPa to 4.57 MPa (round) and 16.66 (rectangular) MPa] in biting with four incisors. Biting with two incisors decreased the stress after splinting [2.42 MPa to 1.7 MPa (round wire) and 1.77 MPa (rectangular wire)]. In lateral movement, all teeth showed an increased stress except for the working side canine. CONCLUSION: Splinted cases (with round or rectangular wires) can benefit from stress redistribution when biting small food particles and in lateral movement.