Accuracy of inlay and onlay restorations based on 3D printing or milling technique - a pilot study.

PURPOSE: To evaluate and compare the accuracy of 3D printing versus CAD/CAM milling in the fabrication of inlay/onlay restorations based on pilot experiments. MATERIAL AND METHODS: Different shaped inlay/onlay cavities were prepared on six extracted and root canal treated human molar teeth. Digital impressions were taken with a CEREC AC Omnicam© intraoral scanner. Based on the same impression data, nano-ceramic restorations were performed using milling (M group) and composite restorations (from material not for clinical use) using Multijet 3D printing technology (3D group). The accuracy was evaluated by measuring the marginal and internal gaps based on x-ray microtomography 3D imaging scans. The internal fit was evaluated using a replica technique with A-silicone impressions and weighing. RESULTS: The 3D group restorations showed better marginal and internal fit values. The mean internal gap values of the 3D group restorations were 40-60% lower compared to the M group restorations, the difference being statistically significant at most measuring points (p⟨0.05, t-test). CONCLUSIONS: The accuracy of the Multijet 3D printing is at least at the same level as the milling technique in the fabrication of dental inlay/onlay restorations. Additional investigations are needed to develop the 3D printing process and suitable materials for dental applications.

Efficacy of stabilisation splint treatment on the oral health-related quality of life-A randomised controlled one-year follow-up trial.

The aim of this randomised controlled trial was to assess the efficacy of stabilisation splint treatment on the oral health-related quality of life OHRQoL during a 1-year follow-up. Originally, the sample consisted of 80 patients (18 men, 62 women) with temporomandibular disorders (TMD) who had been referred to the Oral and Maxillofacial Department, Oulu University Hospital, Finland, for treatment. Patients were randomly designated into splint (n = 39) and control group (n = 41). Patients in the splint group were treated with a stabilisation splint. Additionally, patients in both groups received counselling and instructions on masticatory muscle exercises. The patients filled in the Oral Health Impact Profile-14 (OHIP-14) questionnaire before treatment and at 3 months, 6 months and 1 year. At total, 67 patients (35 in the splint group vs. 32 in the control group) completed the questionnaire at baseline. The outcome variables were OHIP prevalence, OHIP severity and OHIP extent. Linear mixed-effect regression model was used to analyse factors associated with change in OHIP severity during the 1-year follow-up, taking into account treatment time, age, gender and group status. OHIP prevalence, severity and extent decreased in both groups during the follow-up. According to linear mixed-effect regression, decrease in OHIP severity did not associate significantly with group status. Compared to masticatory muscle exercises and counselling alone, stabilisation splint treatment was not more beneficial on self-perceived OHRQoL among TMD patients over a 1-year follow-up.

Diagnostic criteria for temporomandibular disorders (DC/TMD): interexaminer reliability of the Finnish version of Axis I clinical diagnoses.

Recently, updated diagnostic criteria for temporomandibular disorders (DC/TMD) were published to assess TMD in a standardised way in clinical and research settings. The DC/TMD protocol has been translated into Finnish using specific cultural equivalency procedures. To assess the interexaminer reliability using the Finnish translations of the DC/TMD-FIN Axis I clinical diagnostic assessment instruments. Reliability assessment data were collected during a 1-day DC/TMD Examiner Training Course at the University of Turku, Finland, in collaboration with the International DC/TMD Training and Calibration Center in Malmö University. Clinical TMD examinations according to the Finnish pre-final version of the DC/TMD Axis I assessment protocol were performed by four experienced TMD specialists on altogether 16 models. Kappa coefficient, overall percentage agreement (%A) as well as positive (PA) and negative (NA) agreements were used to define the reliability. Myofascial pain with referral, headache attributed to TMD and disc displacement (DD) without reduction without limited opening showed excellent kappa values (range 0·87-1·00). Fair-to-good reliability was observed for diagnoses of myalgia (k = 0·67), arthralgia (k = 0·71) and DD with reduction (k = 0·64). The PA was high for all pain-related diagnoses and DD without reduction without limited opening (medians ≥83%), and acceptable for DD with reduction (median 67%). The NA was high (medians ≥87%) for all DC/TMD diagnoses, except for myalgia which showed acceptable NA (median 75%). The %A was high for all assessed diagnoses (medians >85%). The findings of this study showed DC/TMD-FIN Axis I to demonstrate sufficiently high reliability for pain-related TMD diagnoses.

GWAS Identifies New Loci for Painful Temporomandibular Disorder: Hispanic Community Health Study/Study of Latinos.

Temporomandibular disorder (TMD) is a musculoskeletal condition characterized by pain and reduced function in the temporomandibular joint and/or associated masticatory musculature. Prevalence in the United States is 5% and twice as high among women as men. We conducted a discovery genome-wide association study (GWAS) of TMD in 10,153 participants (769 cases, 9,384 controls) of the US Hispanic Community Health Study/Study of Latinos (HCHS/SOL). The most promising single-nucleotide polymorphisms (SNPs) were tested in meta-analysis of 4 independent cohorts. One replication cohort was from the United States, and the others were from Germany, Finland, and Brazil, totaling 1,911 TMD cases and 6,903 controls. A locus near the sarcoglycan alpha ( SGCA), rs4794106, was suggestive in the discovery analysis ( P = 2.6 × 106) and replicated (i.e., 1-tailed P = 0.016) in the Brazilian cohort. In the discovery cohort, sex-stratified analysis identified 2 additional genome-wide significant loci in females. One lying upstream of the relaxin/insulin-like family peptide receptor 2 ( RXP2) (chromosome 13, rs60249166, odds ratio [OR] = 0.65, P = 3.6 × 10-8) was replicated among females in the meta-analysis (1-tailed P = 0.052). The other (chromosome 17, rs1531554, OR = 0.68, P = 2.9 × 10-8) was replicated among females (1-tailed P = 0.002), as well as replicated in meta-analysis of both sexes (1-tailed P = 0.021). A novel locus at genome-wide level of significance (rs73460075, OR = 0.56, P = 3.8 × 10-8) in the intron of the dystrophin gene DMD (X chromosome), and a suggestive locus on chromosome 7 (rs73271865, P = 2.9 × 10-7) upstream of the Sp4 Transcription Factor ( SP4) gene were identified in the discovery cohort, but neither of these was replicated. The SGCA gene encodes SGCA, which is involved in the cellular structure of muscle fibers and, along with DMD, forms part of the dystrophin-glycoprotein complex. Functional annotation suggested that several of these variants reside in loci that regulate processes relevant to TMD pathobiologic processes.

Association between oral health habits and dental caries among children in Pyongyang, Democratic People's Republic of Korea.

AIM: To evaluate the self-reported oral health habits and their association with the occurrence of dental caries among children in Pyongyang, Democratic People's Republic of Korea (DPRK), after 6 years of activities under the auspices of the Children's Oral Health Promotion Programme (COHPP). METHODS: The data were collected in September 2013 in two of the most central districts of Pyongyang City, DPRK. The sample consisted of 492 children aged 10 and 13 years who had participated in the COHPP for 6 years. The children filled in a self-completed, structured questionnaire on oral health habits and were examined clinically by a dentist. The differences in mean (SD) number of decayed primary (dt) and permanent teeth (DT) and their sum (dt + DT) subdivided according to genders, age groups, districts and self-reported oral health habits were evaluated using Mann-Whitney U-test. The associations between self-reported oral health habits and the occurrence of dental caries were evaluated with chi-square test and logistic regression analyses. RESULTS: The school-aged children commonly reported healthy oral hygiene habits but sweet snacks were commonly used. The occurrence of dental caries associated statistically significantly with the frequency of sweet snacking (p=0.011) but not with the frequency of tooth brushing (p=0.725) or the use of water for thirst instead of sugary beverages (p=0.189). CONCLUSION: A more effective promotion of healthy dietary habits with innovative approaches and close collaboration with different social actors will be needed in future.

Comparison of two preventive interventions on dental caries among children in Democratic People's Republic of Korea.

OBJECTIVES: The aim was to compare the change in dental caries status in two different intervention groups of the Children's Oral Health Promotion Programme (COHPP). METHODS: A longitudinal study among 500 children who had participated into the COHPP for 6 years was conducted in Pyongyang, Democratic People's Republic of Korea (DPRK). Children in Group I received intensified school-based intervention and were clinically examined at the age of 7 years in 2007 (n = 250), 10 years in 2010 (n = 250) and 13 years in 2013 (n = 242). Children in Group II (n = 250) joined the programme at the age of 4 years in kindergarten in 2007, were provided with early preschool-based intervention and were clinically examined at the age of 7 years in 2010 and 10 years in 2013. RESULTS: Both the prevalence and the mean number of dt + DT decreased significantly in both groups during the follow-up. This was due to decrease in the number of dt, whereas the number of DT remained relatively constant. Poisson regression showed that the association between the group status and the change in the number of dt + DT was statistically significant when adjusted for gender but disappeared when the school was included in the analysis. CONCLUSIONS: The decrease in dental caries may be partly due to the exfoliation of deciduous teeth and dental treatment received. However, the study gave some reference emphasizing the early starting of the prevention.

Efficacy of stabilisation splint treatment on facial pain - 1-year follow-up.

The aim of this randomised controlled trial was to assess the efficacy of stabilisation splint treatment on TMD-related facial pain during a 1-year follow-up. Eighty patients were randomly assigned to two groups: splint group (n = 39) and control group (n = 41). The patients in the splint group were treated with a stabilisation splint and received counselling and instructions for masticatory muscle exercises. The controls received only counselling and instructions for masticatory muscles exercises. The outcome variables were the change in the intensity of facial pain (as measured with visual analogue scale, VAS) as well as the patients' subjective estimate of treatment outcome. The differences in VAS changes between the groups were analysed using variance analysis and linear regression models. The VAS decreased in both groups, the difference between the groups being not statistically significant. The group status did not significantly associate with the decrease in VAS after adjustment for baseline VAS, gender, age, length of treatment and general health status. The only statistically significant predicting factor was the baseline VAS, which was also confirmed by the mixed-effect linear model. After 1-year follow-up, 27.6% of the patients in the splint group and 37.5% of the patients in the control group reported 'very good' treatment effects. The findings of this study did not show stabilisation splint treatment to be more effective in decreasing facial pain than masticatory muscle exercises and counselling alone in the treatment of TMD-related facial pain over a 1-year follow-up.

The role of dental loss and denture status on clinical signs of temporomandibular disorders.

Studies concerning the role of denture status on in temporomandibular disorders (TMD) are scarce. The aim of this study was to evaluate the association of tooth loss and denture status with clinical findings of TMD. The data were obtained from 6316 subjects aged ≥ 30 years from the Finnish Health 2000 Survey. The associations between clinically assessed TMD findings and number of teeth, wearing of removable dentures, need for denture repair and age of the dentures were analysed by means of chi-square test and logistic regression. Among women after adjusting for age, having fewer teeth or wearing complete dentures associated with restricted maximum interincisal distance and pain on palpation of the temporomandibular joints (TMJ) and masticatory muscles. After adding education level and depression in the model, the associations between TMJ pain and explanatory variables were weakened. Among men, having a higher number of teeth associated with occurence of TMJ crepitation. Subjective need for repair of dentures and having a denture aged ≥ 5 years associated with pain on palpation in masticatory muscles among women. Among men, both the objective and subjective need for denture repair and having at least one denture aged ≥ 5 years or been repaired during the past 5 years associated negatively with the presence of TMJ crepitation. It can be concluded that edentulousness, wearing of complete dentures and poor condition of dentures associate with pain-related TMD findings among women. Psychosocial factors have a modifying effect on these associations.

Pain-related symptoms of temporomandibular disorders in the offspring of antenatally depressed mothers and depressed parents: a 31-year follow-up of the Northern Finland Birth Cohort 1966.

BACKGROUND: Temporomandibular disorders (TMDs) are clinical problems involving the masticatory muscles and temporomandibular joints (TMJs). Aspects of the aetiology of TMD are controversial. Many studies have identified an association between depression and TMD. The aim of the study was to evaluate the association between both maternal antenatal depression and parental depression during the offspring's childhood with TMD symptoms of the offspring during adulthood and to evaluate the effect of the offspring's own depression on this association. METHODS: In the general population-based Northern Finland Birth Cohort 1966 (NFBC 1966), mothers of 12,058 children were asked at mid-gestation at the antenatal clinic if they felt depressed. Of these offspring who had data available on TMD symptoms in the computer-aided inquiry at the 31-year field study, a final study data of 5541 subjects was compiled. The Finnish Hospital Discharge Register was used to identify depression in the parents between the years 1972 and 1984 (when offspring were 6-18 years old). RESULTS: There were no statistically significant associations between TMD symptoms and maternal antenatal depressed mood. However, parental depression during the offspring's childhood associated significantly with facial pain [adjusted odds ratio (OR) = 1.64; 1.05-2.56] and with TMJ pain at jaw rest (OR = 1.81; 1.13-2.89), even after adjusting for gender, occupation of the father, family type at birth and the offspring's self-reported depression in adulthood. CONCLUSION: The risk for TMD symptoms is not elevated in the offspring of antenatally depressed mothers. Parental depression during an offspring's childhood increases the risk of pain-related TMD symptoms in their early adulthood.

Efficacy of stabilisation splint treatment on temporomandibular disorders.

The evidence supporting the use of stabilisation splints in the treatment of temporomandibular disorders (TMD) is scarce and a need for well-controlled studies exists. The aim of this randomised, controlled trial study was to assess the efficacy of stabilisation splint treatment on TMD. The sample consisted of 80 consecutive referred patients who were randomly assigned to the splint group (n = 39) and the control group (n = 41). Subjects in the splint group were treated with a stabilisation splint, whereas subjects in the control group did not receive any treatment except counselling and instructions for masticatory muscle exercises which were given also to the subjects in the splint group. Outcomes were visual analogue scale (VAS) on facial pain intensity and clinical findings for TMD which were measured at baseline and after 1-month follow-up. The differences in change between the groups were analysed using regression models. Facial pain decreased and most of the clinical TMD findings resolved in both of the groups. The differences in changes in VAS or clinical TMD findings between the groups were not statistically significant. The findings of this study did not show that stabilisation splint treatment in combination with counselling and masticatory muscle exercises has additional benefit in relieving facial pain and increasing the mobility of the mandible than counselling and masticatory muscle exercises alone in a short time-interval.

Residual ridge resorption, lower denture stability and subjective complaints among edentulous individuals.

Residual ridge resorption in the mandible after tooth loss may lead to worsening of complete denture stability and to various subjective complaints. The aim was to evaluate the association between radiologically assessed residual ridge resorption in the mandible, clinically assessed stability of lower complete denture and subjective complaints among elderly denture wearers. The study population consisted of 326 (115 men and 211 women) edentulous subjects aged 60-78years, all of whom were wearing complete dentures in the mandible. Data on subjective complaints were obtained from questionnaires and interviews. Denture stability was assessed clinically. Residual ridge resorption was analysed from panoramic radiographs. The results showed that women were significantly more often satisfied with their lower dentures and reported fewer problems with eating than men. They also had significantly more often residual ridge resorption than men. Among women, residual ridge resorption was significantly associated with poor chewing ability, low satisfaction with dentures and poor denture stability. Among men, residual ridge resorption did not associate with subjective complaints or denture stability. Poor satisfaction with dentures associated significantly with poor denture stability in both genders. In conclusion, these results highlight the importance of denture maintenance treatment. As the extent of residual ridge resorption in the mandible was the most important factor that increased dissatisfaction with lower complete dentures, it is also important to inhibit the progression of resorption by preventing tooth loss or by using implant-retained dentures.

Prevalence of single crowns and fixed partial dentures in elderly citizens in the southern and northern parts of Finland.

The epidemiology of oral rehabilitation using fixed prosthodontics has received little attention. The aim of this study was to evaluate the prevalence of single crowns, fixed partial dentures (FPDs), resin-bonded FPDs and implants in elderly Finnish patients and to identify factors that might be associated with the findings. The survey was carried out in the southern and northern parts of Finland. The target population consisted of all persons born in 1919, 1922, 1925, 1928, 1931, 1934 and 1937, who lived in Kirkkonummi and in Lakeus (n=1733) in 1996. The age range of the subjects was 60-78years. In addition to a clinical examination, panoramic radiograph was taken. Data on background factors were obtained using questionnaires and/or interviews. The presence of single crowns, FPDs, resin-bonded FPDs and implants were determined from the panoramic radiographs. Overall, 12·4% of men and 12·1% of women had single crowns, while 4·8% of men and 8·0% of women had FPDs. A logistic regression analysis showed that the presence of crowns and FPDs was significantly associated with a southern place of residence, high and middle levels of education and high frequency of dental visits.

Influence of edentulousness on gonial angle, ramus and condylar height.

It has been shown that the shape of the mandible correlates with occlusal condition and the function of the masticatory muscles. Edentulous subjects have a wider gonial angle than dentate subjects, and a gender difference has also been shown. However, some studies have reported differing results. Less is known about the effect of dental status and gender on the ramus and condylar height. The aim of this study was to evaluate the association of tooth loss on the shape of mandible (i.e., gonial angle, ramus height and condylar height) in subjects aged 60 years and older. A total of 1036 subjects (667 dentate, 389 edentulous; 554 women and 482 men) were included in the study. Interviews and clinical and panoramic radiographic examinations were carried out. The gonial angle of the mandible and the mandibular and condylar height were measured using panoramic radiographs. In edentulous subjects, the gonial angle was significantly larger, while the ramus and condylar height was significantly smaller on both sides compared with dentate subjects. Women had a significantly larger gonial angle and smaller ramus and condylar height on both sides compared with men. In conclusion, the morphology of the mandible changes as a consequence of tooth loss, which can be expressed as a widening of the gonial angle and shortening of the ramus and condylar height. These findings highlight the importance of rehabilitation of the masticatory system to maintain good functioning of the masticatory muscles for as long as possible.

Prevalence of edentulousness and related factors among elderly Finns.

Edentulousness is a multifactor phenomenon. While its overall prevalence is diminishing, it is increasing in older age groups. The aim of this study was to assess the prevalence of edentulousness among the elderly in two municipalities in Finland and to estimate different factors related to it. All persons born in the years 1919, 1922, 1925, 1928, 1931, 1934 and 1937 living in two municipalities (Kirkkonummi in the southern part of Finland and Lakeus in the northern part of Finland) were invited to participate in the study in 1997. The target population consisted of 1733 subjects of whom 1191 were disposed to participate in a clinical examination performed by two dentists. Of the subjects, 624 were from the southern district (Kirkkonummi) and 566 were from the northern district (Lakeus). The participation rates were 62% and 78%, respectively. The subjects answered a questionnaire comprising sociodemographical data, questions on dental and general health and health behaviour. Logistic regression analysis was used to assess the associations between edentulousness and potential associating factors. The overall prevalence of edentulousness was 37%; being 53% in the northern region and 22% in the southern region. Edentulousness was positively associated with high age [odds ratio (OR = 1.09), confidence interval (CI = 1.06-1.12)], female gender (OR = 2.06, CI = 1.43-2.94), northern place of residence (OR = 2.01, CI = 1.45-2.78), low level of education (OR = 7.09, CI = 3.18-15.81), cardiovascular diseases (OR = 1.51, CI = 1.03-2.21) and current smoking versus never smoking (OR = 1.73, CI = 1.17-2.55). Social factors were more prominently associated with edentulousness than factors related to general health.

Panoramic findings in 34-year-old subjects with facial pain and pain-free controls.

The aim of this study was to compare panoramic radiographic findings between subjects with reported facial pain and pain-free controls in a population-based sample of 34-year olds. The study was a part of a comprehensive medical survey including subjects born in the year 1966 in Northern Finland. A sub-sample of the cohort was formed based on the question concerning facial pain. A panoramic radiograph was taken of 48 subjects with facial pain and 47 pain-free controls. Pathological findings in the dentition, jaws, maxillary sinuses and temporomandibular joints (TMJs) were compared between the groups. The majority of the subjects in both groups did not have pathological findings. Compared with controls, the subjects with facial pain did not show significantly more pathological findings in the teeth, periodontium, maxillary sinuses, TMJs or in the other areas. Radiographic panoramic findings had no association with reported facial pain in the population-based sample of young adults, and have little impact on the diagnosis of facial pain.

Association of symptoms of TMD and orofacial pain with alexithymia: an epidemiological study of the Northern Finland 1966 Birth Cohort.

Alexithymia is a term denoting a deficit in the ability to differentiate emotional from physical states and to identify and describe one's feelings, as well as a preference for external oriented thinking. Alexithymia has been linked with various somatic and psychosomatic diseases, especially with chronic pain. The aim of this study was to evaluate the association between alexithymia and symptoms of temporomandibular disorders (TMD) as well as oro-lingual and dental pain, in a large representative population sample of young adults. The study was a part of the 31-year follow-up study of the Northern Finland Birth Cohort originally consisting of 12058 live births in the year 1966. In 1997, 4893 subjects living in northern Finland or in the capital area, who participated in a field study of the project and later returned a postal questionnaire, made up the sample of this study. Information concerning symptoms of TMD and oro-lingual and dental pain was collected from the subjects. To assess alexithymia, the Toronto Alexithymia Scale-20 (TAS-20) was used. In addition, information about depression, marital status and self-rated health was collected. The proportion of alexithymics (TAS score over 60) was higher in subjects with the most orofacial symptoms than in asymptomatic subjects. In men, alexithymia associated significantly with facial pain, difficulties in mouth opening, oro-lingual pain and dental pain, and in women with pain on jaw movement and dental pain. After adjusting for depression, marital status, and self-rated health, a significant association remained between alexithymia and the symptoms mentioned, except for facial pain in men. It can be concluded that alexithymia is connected with orofacial symptoms. Clinicians treating these symptoms should be familiar with the concept of alexithymia.

Association between symptoms of temporomandibular disorders and depression: an epidemiological study of the Northern Finland 1966 Birth Cohort.

Facial pain and other symptoms of temporomandibular disorders (TMD) are rather common in the adult population. According to clinical studies, psychological factors play an important role in the etiology and maintenance of these symptoms. On the other hand, chronic pain can cause depression. The aim of this study was to evaluate the association between symptoms of TMD and depression in a large population sample of young adults. The study was a part of the 31-year follow-up study of the Northern Finland Birth Cohort consisting of 12,058 live births from the year 1966. Questionnaire information concerning TMD symptoms was collected from a subsample of 5,696 subjects. Depression was measured with a question about reported depression (diagnosed by a doctor) and with the Symptom Checklist depression subscale (SCL-25 DS). Of the TMD symptoms, those related to pain had the most significant relations to indicators of depression. In both genders, the proportion of depression indicated with the SCL-25 DS was significantly higher in subjects with pain-related symptoms of TMD, i.e., facial pain and "pain at jaw rest", and in men with "pain on jaw movement", compared with non-pain subjects (p<0.05). Other symptoms of TMD also associated significantly with SCL-25 DS (p>0.05), except "difficulties in mouth opening" among women. Among women, the prevalence of recognized depression was also significantly higher in subjects with pain-related symptoms of TMD, compared with subjects with no pain (p< or =0.05). Almost all the associations remained significant after adjusting for marital status, education, and self-rated general health. In conclusion, the results show that depression has an association with TMD symptoms, especially those related to pain. When treating patients with facial pain, dentists should consider the possible presence of psychopathology and, if necessary, consult appropriate mental health professionals.

(1S,2R,2'S)- and (1S,2S, 2'S)-1-phenyl-2-phenylthio-2-(tetrahydropyran-2'-ylthio)ethanol diastereoisomers at 193 K.

In the synthesis of 1-phenyl-2-phenylthio-2-(tetrahydropyran-2-ylthio)ethanol, C(19)H(22)O(2)S(2), four diastereoisomers are formed. Two non-centrosymmetric enantiomeric forms which crystallize in space groups P2(1)2(1)2(1) and Pna2(1) are presented. The former has an intramolecular hydrogen bond between the hydroxyl group and the O atom of the tetrahydropyran ring. In the latter isomer, the hydroxyl group forms an intermolecular hydrogen bond to the O atom of the tetrahydropyranyl group of a neighbouring molecule, joining the molecules into chains in the c-axis direction; the O.O distances are 2.962 (4) and 2.764 (3) A, respectively. The tetrahydropyran rings are in chair conformations in both isomers and the S side chain has an equatorial orientation in the former, but an axial orientation in the latter molecule.