Ultrastructure of Dentin Matrix in Heritable Dentin Defects

Heritable dentin defects form a group of diseases which exclusively affect dentin among the various dental tissues. While one type is associated with the generalized connective tissue disorder, osteogenesis imperfecta, other types occur as single traits. The clinical manifestations of the dentin defects vary from insignificant to severe enough to cause aesthetical and functional failure of the teeth. Scanning and transmission electron microscopic studies, reviewed in this paper, have markedly clarified the ultrastructure of the aberrant dentin matrix. Both similar and different changes seem to occur in the various forms of heritable dentin defects. Abnormalities in the appearance and organization pattern of collagen fibers in the defective dentin partly resemble those observed in skin in generalized connective tissue diseases. The similarity of ultrastructural findings in dentin defects, which are currently classified as distinct entities, and even in diseases affecting other tissues, could be related to the complicated interactions between the extracellular matrix macromolecules. Thus, many of the changes observed may be secondary in nature. Ultra-structural studies can help us to understand the pathogenesis of the different types of heritable dentin defects as well as aid in diagnostics and classification of these diseases

The impact of orthodontic treatment on choosing a career in dentistry

Introduction Many studies, globally, have aimed at elucidating reasons to choose a career in dentistry. The most common motives found are reasonable working hours and aspiration to help. The aim of this study was to explore whether eventual past personal experience of orthodontic treatment and particularly the interpersonal skills of the treating orthodontist are of significance in this respect. Materials and methods An electronic questionnaire, consisting of multiple choice and descriptive questions about dental history and experiences in dental care, was sent to dental and, as controls, psychology students within the same Faculty of Medicine, University of Helsinki, Finland. The answers between the two groups were compared and differences tested statistically. Results The questionnaire was answered by 143 (46.0%) dental students and 94 (17.6%) psychology students. Dental students, compared to psychology students, had more positive views of their dentition and dental treatment in general (p = 0.000). Amongst participants, 47.9% of dental students and 57.4% of psychology students had received orthodontic treatment. Of those, dental students had perceived their orthodontic treatment as less painful (p = 0.001) and less uncomfortable (p = 0.000) than psychology students. Moreover, dental students reported more often experiences of orthodontist taking into account their situation in life during treatment (p = 0.011) and gave more positive descriptions of the orthodontist's interpersonal skills (p = 0.031). Conclusions Dental students, compared to psychology students, had statistically significantly more positive personal experiences related to dentistry and orthodontics, supporting our hypothesis that positive experiences with orthodontic treatment likely increase the probability of choosing dentistry as the future career.Peer reviewe

Fatigue and disturbances of sleep in patients with osteogenesis imperfecta - a cross-sectional questionnaire study

Background: Persisting fatigue has been reported to be a common complaint by individuals with connective tissue disorders, including Osteogenesis imperfecta (OI). This controlled study evaluated in an adult OI population the subjective experience of fatigue, affecting daily life. Sleep disturbances and chronic pain were examined as hypothesized underlying factors. Methods: This cross-sectional study analyzed the answers of 56 OI patients and 56 matched healthy controls to a questionnaire, designed to evaluate levels of experienced fatigue and bodily pain, as well as the presence or absence of symptoms related to sleep disturbances or sleep apnea. The relationships between fatigue, pain, and sleep disturbances were evaluated with correlation analysis and regression analysis. Results: Fatigue was reported by 96%, and daily pain by 87% of the individuals with OI. Notably, the level of fatigue was similarly experienced by patient respondents and controls. In total, 95% of the patients and 77% of the controls reported one to several sleep disturbance symptoms. These symptoms as well as previously diagnosed sleep apnea were statistically significantly more prevalent in the patient group than in the controls (p <0.05). Likewise, the experienced bodily pain was statistically highly significantly more severe among the respondents with OI (p <0.001), and correlated with the reported fatigue. Conclusions: In comparison with age-matched controls, adults with OI do not differ in experienced fatigue, unlike hypothesized. Therefore, sleep disturbances, which based on the frequency of reported related symptoms and previous sleep apnea diagnoses appear to be common in OI patients, may remain undiagnosed.Peer reviewe

A review of methods to determine viability, vitality and metabolic rates in microbiology

Viability and metabolic assays are commonly used as proxies to assess the overall metabolism of microorganisms. The variety of these assays combined with little information provided by some assay kits or online protocols often leads to mistakes or poor interpretation of the results. In addition, the use of some of these assays is restricted to simple systems (mostly pure cultures), and care must be taken in their application to environmental samples. In this review, the necessary data are compiled to understand the reactions or measurements performed in many of the assays commonly used in various aspects of microbiology. Also, their relationships to each other, as metabolism links many of these assays, resulting in correlations between measured values and parameters, are discussed. Finally, the limitations of these assays are discussed

The Association between Molar-Incisor Hypomineralization and Dental Caries with Socioeconomic Status as an Explanatory Variable in a Group of Finnish Children

The aim of this study was to investigate if a developmental enamel defect known as Molar-Incisor Hypomineralization (MIH) is associated with dental caries. Socioeconomic status (SES) was examined as a confounding factor between caries and MIH. In this cross-sectional study, 636 children, aged 8 to 13 years, from three towns (two rural areas and one urban area) in Finland were examined for MIH in line with the criteria of the European Academy of Paediatric Dentistry. Caries status for permanent teeth was recorded as decayed, missing and filled teeth (DMFT). Caries experience (DMFT > 0) in the first permanent molars (FPMs) was set as an outcome. SES was determined using a questionnaire completed by parents. The prevalence of MIH was 18.1%. The mean DMFT in FPMs for children with MIH was higher than for their peers, 1.03 +/- 1.25 vs. 0.32 +/- 0.80 (p = 0.000, Mann-Whitney U test). In a multivariate analysis using the generalized linear mixed model where locality, SES, age and MIH were taken into account as caries risk indicators, MIH was the strongest risk indicator of caries in FPMs (Odds Ratio: 6.60, 95% Confidence Interval: 3.83-11.39, p = 0.000). According to the study results, children with MIH have a higher risk for dental caries than children without MIH.Peer reviewe

Determinants of stimulated salivary flow among haematopoietic stem cell transplantation recipients

The aetiology of hyposalivation in haematopoietic stem cell transplantation (HSCT) recipients is not fully understood. This study examined the effects of treatment-related aetiological factors, particularly medications, on stimulated salivary flow in HSCT recipients. Adult HSCT recipients (N = 118, 66 males, 27 autologous and 91 allogeneic transplants) were examined. Stimulated whole salivary flow rates (SWSFR) were measured before HSCT and at 6 and 12 months post-HSCT. Linear regression models were used to analyse the associations of medications and transplant-related factors with salivary flow rates, which were compared to salivary flow rates of generally healthy controls (N = 247). The SWSFR of recipients were lower pre-HSCT (mean +/- standard deviation, 0.88 +/- 0.56 ml/min; P <0.001), 6 months post-HSCT (0.84 +/- 0.61; P <0.001) and 12 months post-HSCT (1.08 +/- 0.67; P = 0.005) than the SWSFR of controls (1.31 +/- 0.65). In addition, hyposalivation (<0.7 ml/min) was more frequent among HSCT recipients pre-HSCT (P <0.001), 6 months post-HSCT (P <0.001) and 12 months post-HSCT (P = 0.01) than among controls. The SWSFR was observed to improve over time being significantly higher 12 months post-HSCT compared to pre-HSCT (P <0.001). The observed decrease of salivary flow could not be explained by the examined transplant-related factors and medications. Decreased stimulated salivary flow rates could not be explained by the examined factors alone; these findings indicate that hyposalivation in HSCT recipients exhibits a multifactorial aetiology. All HSCT recipients should be considered to be at high risk of hyposalivation and consequent oral diseases, and they should be treated accordingly.Peer reviewe

Minimum size and positioning of imaging field for CBCT scans of impacted maxillary canines

Objectives In children and adolescents, cone-beam computed tomography (CBCT) is frequently used for localization of unerupted or impacted teeth in the anterior maxilla. CBCT causes a higher radiation dose than conventional intraoral and panoramic imaging. The objective was to analyze the location of impacted canines in a three-dimensional coordinate and thereby optimize the CBCT field-of-view (FOV), for radiation dose reduction. Materials and methods Location of 50 impacted maxillary canines of children under 17 years was retrospectively evaluated from CBCT scans. The minimum and maximum distances of any part of the right- and left-side canines to three anatomic reference planes were measured to assess the adequate size and position of a cylindrical image volume. Results A cylinder sized 39.0 (diameter)x33.2 (height) mm, with its top situated 13.8 mm above the hard palate, its medial edge 8.4 mm across the midline, and anterior edge 2.5 mm in front of the labial surface of maxillary central incisors fitted all the analyzed canines. Conclusions In this sample, the FOV required for imaging maxillary impacted canines was smaller than the smallest FOV offered by common CBCT devices. We encourage development of indication-specific CBCT imaging programs and aids to facilitate optimum patient positioning.Peer reviewe

Minimum size and positioning of imaging field for CBCT-scans of impacted lower third molars : a retrospective study

Background Cone-beam Computed Tomography (CBCT) is widely used for preoperative 3D imaging of lower third molars. Hence, for this imaging indication, the present study aimed to define the minimum field-of-view (FOV) size and its optimum placement, to decrease radiation exposure, and highlight the need of computer-assisted FOV centering technique for dental CBCT devices. To facilitate proper placement of image field, lower second molar was chosen as reference. Methods The retrospective study included 50 CBCT-scans of 46 patients with mean age of 34 years. Based on the lower second molar, a three-dimensional coordinate was formed and the location of mandibular canal (MC) and the dimensions and locations of the lower third molars, and possible associated pathological findings were assessed. Accordingly, the FOV size and position for third-molar imaging were optimized, while ensuring encompassment of all relevant structures. Results The minimum cylindrical volume, covering lower third molars and MC, was 32.1 (diameter) x 31.6 (height) mm, placed in relation to the second molar crown, top 2.2 mm above cusp tips, anterior edge 6.7 mm in the front of the most distal point of the crown, and lingual edge 7.9 mm on the medial side of the lingual wall. Conclusions The optimized FOV for lower third molars was smaller than common standard small FOVs. We recommend using FOV volume 3.5 null x 3.5 cm for third molars without associated pathology. Accurate FOV protocols are essential for development of new CBCT-devices with computer-assisted and indication-specific FOV placement.Peer reviewe

Dental age estimation in Somali children using the Willems et al. model

AimThe aim of the current study was to retrospectively collect dental panoramic radiographs from Somali children living in Finland, to use the radiographic data to develop a new age estimation model based on the model established by Willems et al. (J Forensic Sci 46(4):893-895, 2001), and to compare the age prediction performances of the Willems et al. model (WM) and the newly developed model.Material and methodsDental panoramic radiographs from 808 healthy Somalis born in Finland were selected. The development of the seven left mandibular permanent teeth, from the central incisor to the second molar, was staged according to Demirjian et al. (Hum Biol 45(2):211-227, 1973). Radiographs with all listed permanent teeth completely developed were excluded. The studied sample consisted of 635 subjects (311 females, 324 males) ranging in age from 4 to 18years. Kappa and weighted Kappa statistics were used to quantify intra- and inter-observer agreement in stage allocation. The collected dataset was used to validate the WM, constructed on a Belgian Caucasian reference sample, and to establish a Somali-specific age estimation model (SM) based on the WM. Both models were validated and their age prediction performances quantified using mean error (ME), mean absolute error (MAE) and root mean squared error (RMSE).ResultsThe SM resulted in a slight underestimation of age when the sex groups were analysed separately or combined, with ME varying between 0.04 (standard deviation (SD) 1.01) and 0.05 (SD 1.04) years, MAE between 0.77 and 0.80years and RMSE between 1.01 and 1.04years. The WM statistically significantly underestimated the age of females, with an ME of 0.20 (SD 1.01) years (p=0.0006). For males, and for females and males combined, no statistically significant ME was observed.ConclusionThe WM and SM were similar in their age prediction performances, and the use of the WM in dental age assessment in the Somali population is justified.Peer reviewe

Dissociations of oral foci of infections with infectious complications and survival after haematopoietic stem cell transplantation

Introduction Haematopoietic stem cell transplantation (HSCT) recipients are at increased risk for severe infections. This study examined the associations of common oral infections with survival and infectious complications in HSCT recipients. Materials and methods All autologous and allogeneic HSCT recipients transplanted in the University Hospital of Basel, Switzerland, between 2008 and 2016 and referred to oral infection control pre-HSCT were included in this retrospective case-control study. All patients had a clinical and a panoramic radiological dental examination taken immediately prior to HSCT. Presence of acute or chronic oral foci of infections, decayed, missing or filled tooth index (DMFT) and radiological attachment loss (RAL) were examined. Survival and infections of the subjects were followed up for 6 months post-HSCT. Results Altogether 341 allogeneic and 125 autologous HSCT recipients were included in the study. Within 6 months post-HSCT, 47 (14%) of the allogeneic and 4 (3%) of the autologous recipients died. Oral foci of infections (acute or chronic), DMFT or periodontitis pre-HSCT were not associated with survival 6 months post-HSCT. Oral foci of infections were also not associated with hospital treated infectious diseases or blood culture positive bacteremia during the 6 month follow-up period. Untreated oral foci of infections were not associated with survival or severe infectious complications within 6 months post-HSCT. Conclusion The results of this study suggest that radical dental interventions to chronic oral infections could be postponed until post-HSCT.Peer reviewe