Dentinogenesis imperfecta type II in Swedish children and adolescents.

BACKGROUND: Dentinogenesis imperfecta (DGI) is a heritable disorder of dentin. Genetic analyses have found two subgroups in this disorder: DGI type I, a syndromic form associated with osteogenesis imperfecta (OI), and DGI type II, a non-syndromic form. The differential diagnosis between types I and II is often challenging. Thus, the present cross-sectional study had two aims: to (i) investigate the prevalence and incidence of DGI type II among Swedish children and adolescents and (ii) search out undiagnosed cases of DGI type I by documenting the prevalence of clinical symptoms of OI in these individuals. We invited all public and private specialist pediatric dental clinics (n = 47) in 21 counties of Sweden to participate in the study. We then continuously followed up all reported cases during 2014-2017 in order to identify all children and adolescents presenting with DGI type II. Using a structured questionnaire and an examination protocol, pediatric dentists interviewed and examined patients regarding medical aspects such as bruising, prolonged bleeding, spraining, fractures, hearing impairment, and family history of osteoporosis and OI. Joint hypermobility and sclerae were assessed. The clinical oral examination, which included a radiographic examination when indicated, emphasized dental variables associated with OI. RESULTS: The prevalence of DGI type II was estimated to be 0.0022% (95% CI, 0.0016-0.0029%) or 1 in 45,455 individuals. Dental agenesis occurred in 9% of our group. Other findings included tooth retention (17%), pulpal obliteration (100%), and generalized joint hypermobility (30%). Clinical and radiographic findings raised a suspicion of undiagnosed OI in one individual, a 2-year-old boy; he was later diagnosed with OI type IV. CONCLUSIONS: These results show a significantly lower prevalence of DGI type II than previously reported and point to the importance of excluding OI in children with DGI.

Tooth agenesis in osteogenesis imperfecta related to mutations in the collagen type I genes.

BACKGROUND: Osteogenesis imperfecta (OI) is a heterogeneous group of disorders of connective tissue, mainly caused by mutations in the collagen type I genes (COL1A1 and COL1A2). Tooth agenesis is a common feature of OI. We investigated the association between tooth agenesis and collagen type I mutations in individuals with OI. SUBJECTS AND METHODS: In this cohort study, 128 unrelated individuals with OI were included. Panoramic radiographs were analyzed regarding dentinogenesis imperfecta (DGI) and congenitally missing teeth. The collagen I genes were sequenced in all individuals, and in 25, multiplex ligation-dependent probe amplification was performed. RESULTS: Mutations in the COL1A1 and COL1A2 genes were found in 104 of 128 individuals. Tooth agenesis was diagnosed in 17% (hypodontia 11%, oligodontia 6%) and was more frequent in those with DGI (P = 0.016), and in those with OI type III, 47%, compared to those with OI types I, 12% (P = 0.003), and IV, 13% (P = 0.017). Seventy-five percent of the individuals with oligodontia (≥6 missing teeth) had qualitative mutations, but there was no association with OI type, gender, or presence of DGI. CONCLUSION: The prevalence of tooth agenesis is high (17%) in individuals with OI, and OI caused by a qualitative collagen I mutation is associated with oligodontia.

Decreased fracture rate, pharmacogenetics and BMD response in 79 Swedish children with osteogenesis imperfecta types I, III and IV treated with Pamidronate.

BACKGROUND: Osteogenesis imperfecta (OI) is an inherited heterogeneous bone fragility disorder, usually caused by collagen I mutations. It is well established that bisphosphonate treatment increases lumbar spine (LS) bone mineral density (BMD), as well as improves vertebral geometry in severe OI; however, fracture reduction has been difficult to prove, pharmacogenetic studies are scarce, and it is not known at which age, or severity of disease, treatment should be initiated. MATERIALS AND METHODS: COL1A1 and COL1A2 were analyzed in 79 children with OI (type I n=33, type III n=25 and type IV n=21) treated with Pamidronate. Data on LS BMD, height, and radiologically confirmed non-vertebral and vertebral fractures were collected prior to, and at several time points during treatment. RESULTS: An increase in LS BMD Z-score was observed for all types of OI, and a negative correlation to Δ LS BMD was observed for both age and LS BMD Z-score at treatment initiation. Supine height Z-scores were not affected by Pamidronate treatment, The fracture rate was reduced for all OI types at all time points during treatment (overall p<0.0003, <0.0001 and 0.0003 for all OI types I, III and IV respectively). The reduced fracture rate was maintained for types I and IV, while an additional decrease was observed over time for type III. The fracture rate was reduced also in individuals with continued low BMD after >4yrs Pamidronate. Twice as many boys as girls with OI type I were treated with Pamidronate, and the fracture rate the year prior treatment was 2.2 times higher for boys (p=0.0236). Greater Δ LS BMD, but smaller Δ fracture numbers were observed on Pamidronate for helical glycine mutations in COL1A1 vs. COL1A2. Vertebral compression fractures did not progress in any individual during treatment; however, they did not improve in 9%, and these individuals were all >11years of age at treatment initiation (p<0.0001). CONCLUSION: Pamidronate treatment in children with all types of OI increased LS BMD, decreased fracture rate, and improved vertebral compression fractures. Fracture reduction was prompt and maintained during treatment, irrespective of age at treatment initiation and collagen I mutation type.

[International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 1. Fractures and luxations of permanent teeth. Hebrew edition].

Traumatic dental injuries (TDIs) of permanent teeth occur frequently in children and young adults. Crown fractures and luxations are the most commonly occurring of all dental injuries. Proper diagnosis, treatment planning and follow up are important for improving a favorable outcome. Guidelines should assist dentists and patients in decision making and for providing the best care effectively and efficiently. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the group. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion of the IADT board members. The guidelines represent the best current evidence based on literature search and professional opinion. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care of TDIs. In this first article, the IADT Guidelines for management of fractures and luxations of permanent teeth will be presented. The Hebrew Edition is part of the IADT global effort to provide accessibility to these guidelines worldwide.

[International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 2. Avulsion of permanent teeth. Hebrew edition].

Avulsion of permanent teeth is one of the most serious dental injuries, and a prompt and correct emergency management is very important for the prognosis. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the task group. The guidelines represent the current best evidence and practice based on literature research and professionals' opinion. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion or majority decision of the task group. Finally, the IADT board members were giving their opinion and approval. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care of avulsed permanent teeth. The Hebrew Edition is part of the IADT global effort to provide a worldwide accessibility to these guidelines. This scond part of the guidelines will focus on avulsion of permanent teeth.

[International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 3. Injuries in the primary dentition. Hebrew edition].

Traumatic injuries to the primary dentition present special problems and the management is often different as compared with the permanent dentition. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialities were included in the task group. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion or majority decision of the task group. Finally, the IADT board members were giving their opinion and approval. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care for management of primary teeth injuries. The IADT cannot and does not guarantee favorable outcomes from strict adherence to the guidelines, but believe that their application can maximize the chances of a positive outcome. The Hebrew Edition is part of the IADT global effort to provide a worldwide accessibility to these guidelines. This third part will discuss injuries in the primary dentition.

Clinical, histopathologic, and genetic investigation in two large families with dentinogenesis imperfecta type II.

Dentinogenesis imperfecta (DI) type II, an inherited disorder affecting dentin, has been linked to mutations in the dentin sialophosphoprotein ( DSPP) gene on chromosome 4q21. The gene product is cleaved into two dentin-specific matrix proteins, dentin sialoprotein (DSP) and dentin phosphoprotein. The aim of this investigation was to study genotypes and phenotypes in two affected families with special reference to clinical, radiographic, and histopathologic manifestations. Seven affected members of Family A and five of Family B were documented clinically and radiographically; 14 and 10 teeth, respectively, were available for histopathologic investigation and prepared for ground sections, which were assessed semiquantitatively for dysplastic manifestations in the dentin according to the scoring system, dysplastic dentin score (DDS). Venous blood samples were collected from six affected and ten unaffected members of Family A, and from eight affected and six unaffected members of Family B. Genomic DNA was extracted and used for sequence analyses. The two families presented with different missense mutations. An Arg68Trp missense mutation in the DSP part of the gene was revealed in all six analyzed affected individuals in Family A. This mutation was not present in any of the ten healthy members. In Family B, an Ala15Val missense mutation involving the last residue of the signal peptide was found in all eight affected but in none of the six healthy members. The clinical and radiographic disturbances and DDS were more severe in Family B. The data indicate the presence of a genotype-phenotype correlation in DI type II.

Decoronation: how, why, and when?

Decoronation is a surgical method for treating ankylosed incisors in children and adolescents. The crown and root filling are removed, leaving the root in situ to be resorbed and covered with a mucoperiosteal flap. Early loss of a permanent tooth leads to loss of alveolar bone, especially in buccopalatal width. Decoronation preserves not only the width of the ridge but also the vertical height.

The problem of dentoalveolar ankylosis and subsequent replacement resorption in the growing patient.

Dentoalveolar ankylosis is a serious complication following injuries of the periodontal membrane in severe dental trauma such as avulsion and intrusion. The condition is a fusion of the alveolar bone with the tooth. The consequences of this condition are progressive resorption of the root with replacement by bone (replacement resorption) and arrested growth of the alveolar process in the growing patient. This article will present an overview of dentoalveolar ankylosis and replacement resorption and its problems, treatment options and prognosis, especially focusing on the growing patient.

Rapid orthodontic extrusion of crown root and cervical root fractured teeth.

This study concerns the relapse tendency and extent of root resorption in 33 extruded non-vital crown root fractured or cervical root fractured teeth in 32 patients 10-20 years old. They constitute all orthodontically extruded teeth at the Orthodontic or Pedodontic Departments, Eastman Institutet, Stockholm (1982-1987). A simple extrusion mechanism exerted a force of 60-70 p along the root axis of the tooth. An extrusion of 2-3 mm was obtained in most patients; the most extreme effect was 6 mm. In 16 patients the extrusion was achieved within 3 weeks, in 12 it lasted for 4-6 weeks and in 5, 7-9 weeks. The treatment was more complicated in the lower jaw. After the extrusion, a fibrotomy was done and in most patients also a gingival recontouring to create an optimal relation between the gingiva and the margin of the restoration. Periodically identical radiographs were taken immediately before and after the extrusion, after 3 months and after 1 year. A minor relapse, about 0.5 mm, was observed in 3 patients. Limited root resorption was found in 6 teeth and severe in only 1. The resorptions did not progress in the following 2 years of observation.

Dentinogenesis imperfecta in a six-generation family. A clinical, radiographic and histologic comparison of two branches through three generations.

Dentinogenesis imperfecta type II through 2 branches of a 6-generation family was presented focusing on individual differences in clinical, radiographic and histological appearances. These differences lead to different treatment approaches emphasizing prevention of attrition in order to avoid loss of vertical height and development of periapical lesions.

The effect of regular professional plaque removal on dental caries in vivo. A polarized light and scanning electron microscope study.

This study aims to describe the histological and ultrastructural enamel reactions to regular disturbance/removal of dental plaque, using an in vivo caries model. Fourteen young volunteers undergoing orthodontic treatment participated in the study. To create local protected areas, orthodontic bands with a buccal space were placed in homologous pairs of premolars. One tooth in each pair served as control and had the band cemented for the entire test period of 5 weeks. The other band was removed weekly and the buccal surface cleaned, either by careful pumicing with a nonfluoride toothpaste, or by simple cleaning with a cotton pellet. Results indicated that 5 weeks with completely undisturbed plaque accumulation resulted in visible enamel demineralization in all 14 individuals, whilst a weekly performed professional plaque removal was able to prevent lesion progress independent of the cleaning procedure. It is therefore concluded that regular mechanical disturbance of dental plaque is able to suppress bacterial activity and hence caries development.

Clinical and radiographic appearance of proximal carious lesions at the time of operative treatment in young permanent teeth.

Clinical tissue changes were recorded during restorative treatment of proximal carious lesions of young premolars and molars. 60 proximal surfaces with radiolucencies in the inner half of the enamel or the outer half of the dentin were treated. The extent and character of the tissue changes were documented with photographs taken during drilling and evaluated after magnification. The maximum extent for each lesion was correlated to the extent of the radiographically observed lesion. The results showed that 70% of the restored surfaces were associated with a breakdown of the enamel surface. When the radiolucency did not extend deeper than into the inner half of the enamel, cavities were found in 61%; for lesions with a radiolucency extending into the outer half of the dentin the percentage was 78%. In the majority of cases the cavity was limited to the enamel. In all cases discoloration was observed in the enamel. The dentin was soft and discolored in 83%. Severe damage of tooth substance was found in 12% of the teeth.

Surgical treatment of ankylosed and infrapositioned reimplanted incisors in adolescents.

A method for preserving the alveolar ridge of ankylosed and infrapositioned incisors and improving conditions for a subsequent prosthetic therapy is described and evaluated clinically and radiographically. The method involves removal of the crown and root filling from the root, which is retained and covered with a mucoperiosteal flap. Clinically, there were no postoperative complications and after the follow-up a satisfactory prosthetic restoration was performed in all cases, regardless of the degree of infraposition before treatment. Radiographically, no pathologic changes were observed apart from a continuous resorption and replacement of lost root substance by bone. Alveolar bone level shifted only slightly between postoperative and 12-month follow-up radiographs, in a majority of cases in a coronal direction.

Species formation through punctuated gradualism in planktonic foraminifera.

Detailed analysis of evolutionary changes in a 10-million-year long Late Neogene lineage of planktonic foraminifera has revealed a pattern that is not consistent with either the gradualistic or the punctuational model of evolution. The lineage was in stasis over a considerable part of its total duration but underwent relatively rapid, but not geologically instantaneous, gradual morphologic change that did not lead to lineage splitting. The term punctuated gradualism is suggested for this evolutionary modality.

Desensitization of dentin by resin impregnation: a clinical and light-microscopic investigation.

Desensitization of dentin by resin impregnation and the pulpal effect of impregnation procedures were studied in fifty-one pairs of contralateral exposures located on cuspal tips of young premolars. One surface in each pair was impregnated. Pretreatment consisted of etching, antibacterial cleaning and desiccation. Concise Enamel Bond was used for impregnation. Excess was removed or reduced before polymerization. The sensitivity to probing and compressed air was tested after seven to eighteen days. The impregnated surface was less sensitive than the untreated one in forty-one pairs. No difference was reported by nine patients. Twenty-nine impregnated and three untreated surfaces were insensitive to testing. In most histologically examined teeth, impregnated or not, a local, slight inflammation was seen in the pulp horn. Microorganisms usually penetrated some dentinal tubules. Resin impregnation as applied in the present study could reduce or eliminate the sensitivity of exposed dentin, but did not prevent infectious irritation of the pulp.

Reaction of endotoxin and surfactants. I. Physical and biological properties of endotoxin treated with sodium deoxycholate.

Ribi, E. (Rocky Mountain Laboratory, Hamilton, Mont.), R. L. Anacker, R. Brown, W. T. Haskins, B. Malmgren, K. C. Milner, and J. A. Rudbach. Reaction of endotoxin and surfactants. I. Physical and biological properties of endotoxin treated with sodium desoxycholate. J. Bacteriol. 92:1493-1509. 1966.-Endotoxins from three species of gram-negative bacteria were shown to be dissociated by the bile salt sodium deoxycholate (NaD) into nontoxic subunits with molecular weights of about 20,000. When the bile salt was removed by dialysis, the subunits reaggregated in an orderly manner to form a relatively uniform population of biologically active endotoxin particles with average molecular weights of 500,000 to 1,000,000. If a small amount of human plasma was added to the dissociated endotoxin before removal of the NaD, reassociation apparently did not occur and the preparation remained nonpyrogenic. However, the plasma protein could subsequently be removed from the endotoxin subunits, and reaggregation to the toxic form would then occur. The studies on the physical nature of endotoxin performed with biophysical solution techniques were supplemented and confirmed by direct examination of the endotoxin polymers by electron microscopy. The results of these studies were consonant with the theory that the biologically active endotoxic elements are composed of micellar aggregates of linear lipopolysaccharide subunits.