Jean-Marc Retrouvey

Linear measurements using virtual study models.

OBJECTIVE To perform a systematic review of the literature to assess the reliability and validity of linear measurements using virtual vs plaster study models. MATERIALS AND METHODS A search strategy was developed for four online databases, and references were further hand searched for studies additional papers. Three researchers determined the eligibility of papers by applying specific selection criteria and ultimately selected 17 papers. Grouped by virtual model acquisition type and the number of landmarks used in a given measurement, the data were weighted by sample size and analyzed in terms of the reliability and validity of linear measurements. RESULTS The intrarater reliability was high for two-landmark and >two-landmark linear measurements performed on laser-acquired models or cone-beam computed tomography (CBCT)-acquired models and were similar to measurements on plaster models. Validity was high for two-landmark and >two-landmark linear measurements comparing laser-acquired models or CBCT-acquired models to plaster study models, and the weighted mean differences were clinically insignificant. Agreement of measurements was excellent, with less variability than correlation. Acquisition type had no perceived influences on reliability and validity. More than two-landmark measures tended to have higher mean differences than two-landmark measures. CONCLUSIONS Virtual study models are clinically acceptable compared with plaster study models with regard to intrarater reliability and validity of selected linear measurements.

Development of a composite resin disclosing agent based on the understanding of tooth staining mechanisms

OBJECTIVES To characterize the surface composition of dental enamel and composite resin, assess the ability of dyes with different affinities to stain these surfaces, and use this information to develop a disclosing agent that stains composite resin more than dental enamel. METHODS One hundred and ten sound extracted teeth were collected and 60 discs of composite resin, 9 mm diameter and 3 mm thick, were prepared. X-ray photoelectron spectroscopy (XPS) was employed to determine the elemental composition on the different surfaces. A tooth shade spectrophotometer was used to assess the change in shade after staining the surfaces with different dyes. RESULTS XPS analysis revealed that surfaces of both outer dental enamel and composite resin contained relatively high amounts of carbon, specifically hydrocarbons. Both dental enamel and composite surfaces were stainable with the hydrophobic dye (p<0.05); however, the composite resin was stained more than the dental enamel (p<0.05). CONCLUSIONS The hydrophobic surface of dental enamel and composite resin might explain their high affinity to be stained by food and beverages containing hydrophobic molecules. The composite resin is more stainable by hydrophobic dyes than dental enamel. We used this information to develop an agent for disclosing composite resins that could be used to visualize composite resins that need to be removed. CLINICAL SIGNIFICANCE Removal of composite resin can be problematic, time consuming and stressful to the dental practitioner. A composite disclosing agent would help the dental practitioner identify the composite resin and facilitate its removal without damaging the adjacent healthy tooth tissues.

Oral-Facial Aspects of Osteogenesis Imperfecta

The axial skeleton is affected to a variable degree in the different forms of osteogenesis imperfecta (OI). The pleiotropic effect also often involves the dentition and craniofacies, with approximately half of those with OI also having dentinogenesis imperfecta (DI). The incidence of DI is greater in the more severely affected viable class types (VI and III), which also tend to express the more severe effect on craniofacial growth. There are other dental abnormalities in addition to DI, including impacted teeth. The alteration in craniofacial growth starts with the cranial base, and extends to hypoplasia of the maxilla and relative prognathism of the mandible. This typically develops into a negative anterior overjet and a Class III malocclusion. Posterior open-bites also occur, which are extremely resistant to treatment. Orthognathic surgery is possible to treat the skeletal malocclusion on a case-by-case basis. Bisphosphonate use may slow orthodontic tooth movement, but appear to present a very low risk of osteonecrosis of the jaws if dental extractions are indicated.

Dental Development and Maturation, from the Dental Crypt to the Final Occlusion

Publisher Summary The formation and maturation of dental tissues constitute an important process in craniofacial development. Genes coding the expression of growth factors, transcription factors and extracellular matrix molecules regulate this process. Tooth eruption through the dental follicle is a complex phenomenon. It involves osteoblastic and osteoclastic activity that contributes to form dentoalveolar bone. This bone formation and the development of dental occlusion, first for the deciduous, then for the succedaneous dentition, has a profound impact on the development of the lower part of the face. The mode of tooth eruption, guided by precise genetic control, is influenced by its neuromuscular environment and the response of the periodontal ligaments to the environment. Tooth positioning is altered by functional imbalance; as the periodontal ligament responds to forces and rapidly remodels the dentoalveolar complex in order to maintain the necessary physiological distance between the alveolar wall and the dental root.

Dental and facial characteristics of osteogenesis imperfecta type V

Osteogenesis imperfecta (OI) type V is an ultrarare heritable bone disorder caused by the heterozygous c.-14C>T mutation in IFITM5. The dental and craniofacial phenotype has not been described in detail. In the present multicenter study (Brittle Bone Disease Consortium) 14 individuals with OI type V (age 3 to 50 years; 10 females, 4 males) underwent dental and craniofacial assessment. None of the individuals had dentinogenesis imperfecta. Six of the 9 study participants (66%) for whom panoramic radiographs were obtained had at least one missing tooth (range 1 to 9). Class II molar occlusion was present in 8 (57%) of the 14 study participants. The facial profile was retrusive and lower face height was decreased in 8 (57%) individuals. Cephalometry, performed in three study participants, revealed a severely retrusive maxilla and mandible, and poorly angulated incisors in a 14-year old girl, a protrusive maxilla and a retrusive mandible in a 14-year old boy. Cone beam computed tomograpy scans were obtained from two study participants and demonstrated intervertebral disc calcification at the C2-C3 level in one individual. Our study observed that OI type V is associated with missing permanent teeth, especially permanent premolar, but not with dentinogenesis imperfecta. The pattern of craniofacial abnormalities in OI type V thus differs from that in other severe OI types, such as OI type III and IV, and could be described as a bimaxillary retrusive malocclusion with reduced lower face height and multiple missing teeth.

Caries Prevalence and Experience in Individuals with Osteogenesis Imperfecta

Objective Dentinogenesis Imperfecta (DI) forms a group of dental abnormalities frequently found associated with Osteogenesis Imperfecta (OI), a hereditary disease characterized by bone fragility. The objectives of this study was to quantify the caries experience among different OI-types and quantify how these values change due to DI. Methods To determine which clinical characteristics were associated with increased CPE in patients with OI, the adjusted DFT scores were used to account for frequent hypodontia, impacted teeth and retained teeth in OI population. Results The stepwise regression analysis while controlling for all other variables demonstrated the presence of DI (OR 2.43; CI 1.37 to 4.32; p=0.002) as the significant independent predictor of CPE in the final model. Conclusion This study found no evidence that CPE of OI subjects differs between the types of OI. The presence of DI when controlled for other factors was found to be the significant predictor of CPE.

Osteogenesis imperfecta: potential therapeutic approaches

Osteogenesis imperfecta (OI) is a genetic disorder that is usually caused by disturbed production of collagen type I. Depending on its severity in the patient, this disorder may create difficulties and challenges for the dental practitioner. The goal of this article is to provide guidelines based on scientific evidence found in the current literature for practitioners who are or will be involved in the care of these patients. A prudent approach is recommended, as individuals affected by OI present with specific dentoalveolar problems that may prove very difficult to address. Recommended treatments for damaged/decayed teeth in the primary dentition are full-coverage restorations, including stainless steel crowns or zirconia crowns. Full-coverage restorations are also recommended in the permanent dentition. Intracoronal restorations should be avoided, as they promote structural tooth loss. Simple extractions can also be performed, but not immediately before or after intravenous bisphosphonate infusions. Clear aligners are a promising option for orthodontic treatment. In severe OI types, such as III or IV, orthognathic surgery is discouraged, despite the significant skeletal dysplasia present. Given the great variations in the severity of OI and the limited quantity of information available, the best treatment option relies heavily on the practitioner’s preliminary examination and judgment. A multidisciplinary team approach is encouraged and favored in more severe cases, in order to optimize diagnosis and treatment.

Dental and craniofacial characteristics caused by the p.Ser40Leu mutation in IFITM5

Severe forms of osteogenesis imperfecta (OI) are usually caused by mutations in genes that code for collagen Type I and frequently are associated with craniofacial abnormalities. However, the dental and craniofacial characteristics of OI caused by the p.Ser40Leu mutation in the IFITM5 gene have not been reported. We investigated a 15‐year‐old girl with severe OI caused by this mutation. She had marked deformations of extremity long bones. There were no clinical or radiological signs of dentinogenesis imperfecta, but one tooth was missing and several teeth were impacted. Cone beam computed tomography revealed a generalized osteopenic appearance of the craniofacial skeleton, bilateral enlargement of mandibular bodies, and areas of cortical erosions. The cranial base and skull showed a generalized granular bone pattern with a mixture of osteosclerosis and osteolysis. Sphenoid and frontal sinuses were congenitally missing. Cephalometric analysis indicated a Class III growth pattern. In this case, the IFITM5 p.Ser40Leu mutation did not affect tooth structure but was associated with deformities in craniofacial bones that resemble those in the other parts of the skeleton.

Metal-composite adhesion based on diazonium chemistry

OBJECTIVE Composite resins do not adhere well to dental alloys. This weak bond can result in failure at the composite-metal interface in fixed dental prostheses and orthodontic brackets. The aim of this study was to develop a new adhesive, based on diazonium chemistry, to facilitate chemical bonding between dental alloys and composite resin. METHODS Samples of two types of dental alloys, stainless steel and cobalt chromium were primed with a diazonium layer in order to create a surface coating favorable for composite adhesion. Untreated metal samples served as controls. The surface chemical composition of the treated and untreated samples was analyzed by X-ray photoelectron spectroscopy (XPS) and the tensile strength of the bond with composite resin was measured. The diazonium adhesive was also tested for shear bond strength between stainless steel orthodontic brackets and teeth. RESULTS XPS confirmed the presence of a diazonium coating on the treated metals. The coating significantly increased the tensile and shear bond strengths by three and four folds respectively between the treated alloys and composite resin. CONCLUSION diazonium chemistry can be used to develop composite adhesives for dental alloys. SIGNIFICANCE Diazonium adhesion can effectively achieve a strong chemical bond between dental alloys and composite resin. This technology can be used for composite repair of fractured crowns, for crown cementation with resin based cements, and for bracket bonding.