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.

A 5-year follow-up study on one-stage implants inserted concomitantly with localized alveolar ridge augmentation.

The aim of this study was to evaluate the success of one-stage implants placed at the time of alveolar bone augmentation using simultaneous guided bone regeneration technique with a collagen barrier membrane in patients suffering from insufficient bone width. Seventeen patients were treated with 20 one-stage OSTEOFIX (Oulu, Finland) implants using simultaneous guided bone regeneration technique. Dehiscence defects were filled by bovine bone mineral Bio-Oss and covered with collagen membrane. Clinical and radiographic parameters of the peri-implant conditions were assessed at the moment of prosthesis placement and at 1- and 5-year follow-ups. Diagnostic dehiscence defect measurements after implant placement showed that the mean vertical defect varied from 3.8 mm to 10.0 mm. At the moment of prosthesis placement and at 1- and 5-year follow-ups all implants were stable, painless and without biological complications. Clinical and radiographic parameters of the peri-implant conditions remained stable during follow-up. The cumulative implant survival rate was 100% after the 5-year observation period and the success rate for all pooled implants was 90%. The present study showed predictable treatment outcomes recorded after 5 years of function for one-stage OSTEOFIX (Oulu, Finland) oral implants placed simultaneously with guided bone regeneration using collagen membrane and deproteinized bovine bone mineral.

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.

Longevity of fixed metal ceramic bridge prostheses: a clinical follow-up study.

The aim of this study was to evaluate the factors that influence the longevity of fixed metal ceramic bridge prostheses, including the length of the bridge as well as the basic circumstances of the mouth. A total of 132 patients attended the clinical examination. There were 84 women (64%) and 48 men (36%). Patients had altogether 195 bridges, which included 157 short bridges (3-5 units) and 47 long bridges (6 and more units). The overall clinical examination was performed including the intra-oral radiographs. The salivary findings of the patient at baseline [flow rate of stimulated saliva, scores of mutans streptococci (SM) and lactobacilli (LB)] were registered from the patient files. In addition, the patient files were examined to receive further information concerning the complications treated in our clinic. On the basis of severe and extensive complications, the overall survival after 10 years was 84%. Long bridges had lower survival than the shorter ones (P=0.04). A low secretion of saliva recorded before the prosthetic treatment decreased the survival of the bridges (P=0.12) and the survival of the bridges was likewise reduced by high scores of LB and SM (P=0.07). Age of the patient did not influence the survival. It was shown here that long bridges (5 and more units) have a lower survival than the short bridges. It can be concluded, however, that the low secretion of saliva and the high scores of lactobacilli and SM have a remarkable influence on complications and these facts should therefore be taken into careful consideration in choosing the patients for the prosthetic treatment with fixed prosthodontics.

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.

MRI findings concerning the lateral pterygoid muscle in patients with symptomatic TMJ hypermobility.

Clinical studies have shown a close association between temporomandibular joint hypermobility (TMJH) and temporomandibular disorders (TMD). While pathological change of the lateral pterygoid muscle (LPM) is one of the most emphasized in studies of TMD, there have been no detailed clinical reports of the LPM studies using magnetic resonance imaging (MRI) in TMJH. This study investigates structural and pathological alterations involving the LPM in patients with TMJH using MRI. A retrospective analysis was made of high-field MRI images from 98 patients with TMJH. LPMs of 143 joints were analyzed. In 110 joints (77%), hypertrophy, atrophy, and contracture were found in the superior belly and/or the inferior belly of the LPM. Pathological changes were more frequently found in the superior rather than the inferior belly of the LPM. In the cases with abnormalities in both bellies of the LPM, hypertrophy of the inferior belly was usually found combined with other changes of the SBLPM. The results of this study indicated that the pathological changes of the LPM or MRI are not infrequent in patients with symptomatic TMJH.

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.

Treatment need for fixed metal ceramic bridge prostheses in patients treated by dental students in 1984-1996.

Even if implant therapy is very common nowadays, treatment with conventional fixed bridge prosthesis still has indications and cannot be forgotten. Because of improved dental health more teeth can be preserved and more fixed prostheses are prepared also for the elderly. The aim of this study was to discuss the future of treatment need in fixed metal ceramic bridge prostheses based on the analysis of distribution of pontics in dentition in four different age groups during the years 1984-1996. Data were collected from the patient files. The numbers of upper lateral incisors, upper first premolars and lower first molars were analysed in years 1984-1987, 1988-1992 and 1993-1996 between and within age groups of under 34, 35-49, 50-64 years and over 65 years. As a conclusion, in the future the treatment need for fixed bridge prostheses will be highest among patients over 50 years and their most replaced teeth are, besides lower first molars, the upper first premolars.

Influence of previous restoration of the tooth on prognosis of crowns with dowels.

Due to extensive loss of tooth substance the restoration of endodontically treated tooth requires intracanal dowels to give an efficient strength for the crown. The aim of our study was to investigate whether the previous type of restoration of the tooth, i.e. composite restoration with screw post versus one-piece dowel crown, has an effect on the prognosis of crowns with dowels. The material consisted of 111 single crowns and as a previous restoration there were 83 composite restorations with screw posts and 28 one-piece dowel crowns. The mean follow-up time was 78 months (range 6--163 months). The cumulative survival was 87% for one-piece dowel crowns and 84% for composite resins with screw posts. There were six root fractures, four losses of cement retention and one tooth extraction due to caries in crowns with previous composite resin with screw posts. In one-piece dowel crowns as a previous restoration there were two root fractures and one tooth extraction for periodontal reasons. In conclusion, it seems that the previous restoration has no marked effect on the prognosis of crowns with dowels when studying a composite resin restoration with screw post and a one-piece dowel crown.

Facial pain and temporomandibular disorders: an epidemiological study of the Northern Finland 1966 Birth Cohort.

Recent clinical studies have shown an association between temporomandibular disorders (TMD) and facial pain. The aim of this epidemiological study was to investigate the prevalence of facial pain and TMD, their relation to each other, and also their relation to previous traumas, occlusal factors and pain in other areas of the body. The study is a part of the Well-Being and Health Research of the Northern Finland Birth Cohort 1966 using questionnaires where data on facial pain, TMD symptoms, occlusal divergencies, traumas in the face and other pain areas of the body were registered. Data were obtained from 5696 subjects born in the year 1966 in northern Finland. Twelve percent of the men and 18% of the women had suffered from facial pain during the last year. The most often reported symptom of TMD was clicking of the temporomandibular joints (TMJs) (21% in men, 28% in women), while prevalence of more severe symptoms was 13% or under. Facial pain was related to symptoms of TMD, as well as to traumas in the face or TMJs, distal occlusion and other pain areas (neck, shoulders, arms, lower back, jaws, tooth). The results suggest that facial pain is a usual symptom in adult population, and has an association with TMD, as well as with other musculoskeletal pain symptoms. Traumas to face and TMJs, certain occlusal factors and dental pathology may have a remarkable role in the etiology.

The effect of surgical treatment of the temporomandibular joint: a survey of 70 patients.

Most patients with temporomandibular disorders (TMD) can be successfully treated by conservative methods, but approximately 10-20 percent have persistent symptoms. The aim of this study was to evaluate the signs and symptoms of TMD in patients treated with open surgery of the TMJ. Seventy-two patients (13 men, 59 women, mean age 37 years, range 14-68 years) were evaluated during an eight-year period. Altogether 45 right TMJs and 39 left TMJs were treated, including both TMJs during the same operation in eight of the cases. The patients were evaluated at follow-up in 1997. The degree of TMD at follow-up was assessed using the anamnestic and clinical dysfunction Helkimo indices. Most of the patients reported at the follow-up that they were subjectively satisfied with the surgical treatment. The main clinical findings in the post surgical patients at follow-up were TMJ sounds and deviation of the mandible during opening. The tenderness in the masticatory muscles and TMJs on palpation was reduced significantly and the ranges of mandibular movement were improved for all the patients. The mean anamnestic and clinical indices decreased with a statistical significance from the shortest follow-up group (Group I) to the longest on group (Group IV) (p = 0.000). The conclusion of this study was that after open surgical treatment of the TMJ, the patients have significantly better functioning of the masticatory system and reduced signs and symptoms of TMD in the long term.

Role of temporomandibular disorders (TMD) in facial pain: occlusion, muscle and TMJ pain.

Temporomandibular disorders (TMD) which comprise myogenic and arthralgic components have been reported to predispose subjects to headache and facial pain. The aim of this study was to evaluate the role of these components in patients with facial pain and to investigate the influence of treatment of TMD on pain of these patients. The subject group consisted of 25 patients suffering from facial pain. The clinical stomatognathic examination was performed before conservative treatment of TMD, and one-two weeks, three months and one year after treatment. The severity of TMD was assessed using the anamnestic (AI) and clinical dysfunction (DI) indices of Helkimo. The intensity of pain was evaluated on a numerical rating scale (NRS). According to clinical findings the patients were classified to following diagnostic subgroups: TMD myo (mainly myogenic), TMD arthro (mainly arthrogenous) and TMD comb (both myogenic and arthrogenous components involved). Fifteen patients were classified in the TMD myo group, nine in the TMD comb group and one in the TMD arthro group. The DI index decreased significantly one-two weeks after treatment and remained at this level at three month and one year follow-up examinations. At the first examination the TMD myo group had the highest level of NRS index, which decreased significantly during the time of follow-up, while no significant changes were found in other groups. Bruxism reported by the patient had a positive correlation with the amount of painful muscles on the right side at first examination. The results show that facial pain combined with TMD may be mostly of myogenic origin, and myogenic pain seems to have most favorable response to conservative treatment of TMD.

Complications and primary failures related to fixed metal ceramic bridge prostheses made by dental students.

Porcelain fused to metal provides better aesthetics in fixed partial dentures than veneers with gold-resin that were used formerly. The aim of our study was to evaluate complications and primary failures of fixed metal ceramic bridge prostheses made by dental students. We studied 61 patients (32 women, 29 men, mean age 49 years, range 28-73 years) treated during years 1990-1993. Data were collected from the patient files. Altogether 82 bridges were made (mean 4.1 units, range 2-6), 221 abutments (mean 2.7, range 2-6) and 136 pontics (mean 1.6, range 1-4). Forty-seven cast cores were used in 29 bridges (mean 0.4 cores, range 1-3) and semiprecious attachments as an extra attachment in two bridges. Seven teeth were extracted due to complication and/or failure during endodontic treatment and root canal perforation during preparation. In two cases the abutment tooth was fractured by removing the old crown. Four unsuccessful bridges were remade and in seven cases the firing of porcelain was renewed. The study concludes that most common failures of fixed metal ceramic bridges made by dental students occur during root canal preparation of abutment teeth.

Occlusal and temporomandibular joint disorders in patients with unilateral condylar fracture. A prospective one-year study.

Adult dentate patients with unilateral condylar fractures were followed up for one year after injury. Patients were interviewed about subjective complaints, and mandibular excursions and function of occlusion and temporomandibular joints (TMJs) were recorded. Radiological characteristics were assessed from panoramic and Towne's views and compared between patients with occlusal disorders and patients without. During follow up, mandibular deviation on opening towards the fractured side was more pronounced in cases with marked reduction of ramus height and condylar dislocation. This restriction of translation movement of the fractured joint was also seen radiologically in one-third of cases while in two-thirds of the fractured condyles, malpositioning was observed when compared with the healthy side. In patients (39%) having subjective symptoms such as TMJ pain, altered occlusion or ability to bite only unilaterally, and objectively verified occlusal interferences, a marked reduction of the ramus height on the fractured side was observed. In such cases nonoperative treatment of condylar fractures may be compromised.

Effect of edentulousness on mandibular size and condyle-fossa position.

Modern imaging methods make possible the more precise examination of the complicated bony structure of the temporomandibular joint (TMJ) and the performance of cephalometric analysis. The aim of our study was to analyse the effect of edentulousness on the mandibular size and the condyle-fossa position using roentgencephalograms and axial computed tomography (CT) scans. The study group consisted of 20 edentulous patients (14 women, six men, mean age 60 years) whose mean period of edentulousness was 20 years (range 3-34 years). A CT examination of their TMJs was performed and roentgen-cephalograms in 16 of this group were taken after prosthetic treatment. Sixteen dental students were chosen according to sex as controls. Earlier CT scans of 49 dentate subjects of both sexes were used as controls for the analysis of bicondylar asymmetry. The position of the glenoid fossa was more anterior in edentulous subjects than in dentate ones and its anterior position correlated significantly (P < 0.02) with the period of edentulousness, a finding which has not been confirmed before. It can be concluded that the fossa is a remodelling unit as a part of the functional entity when the function is altered dramatically as in the case of edentulous patients.

Follow-up treatment after surgery of internal derangement of temporomandibular joint--a survey of 20 patients.

The effect of surgical treatment of internal derangement of temporomandibular joint (TMJ) combined with regular follow-ups was evaluated in 20 patients (16 women, 4 men, mean age 38 years, range 17-58 years). The function of the masticatory system was examined before surgery and at 3 months, 6 months and 1 year afterwards. The follow-up treatment immediately after operation included the use of analgesics for two to four weeks and mobilization exercises of the lower jaw, beginning the day after the operation. Twelve patients had complete or virtually complete dentition and six patients had prosthesis. The occlusal adjustment and occlusion of the prosthesis was corrected or new prosthesis was constructed approximately six months after surgery. Degree of temporomandibular disorders (TMD) was assessed using the clinical dysfunction index of Helkimo. A statistically significant decrease (p < 0.001) was seen in the scores of the dysfunction index in all recordings after surgery compared to preoperative values. All the ranges of the mandibular movements increased statistically significantly. It seems that regular follow-ups and adequate oral rehabilitation after surgery of internal derangement of TMJ have a great influence on the outcome of the surgical treatment of TMJ.

Densities and sizes of main masticatory muscles in patients with internal derangements of temporomandibular joint obtained by computed tomography.

Computed tomography (CT), due to its excellent resolution capacity, is a suitable method to examine the soft and bony structures of the masticatory system. The aim of this study was to compare densities and sizes of the masseter and medial and lateral pterygoid muscles obtained by CT between the symptomatic and asymptomatic side in patients with internal derangement of the temporomandibular joint (TMJ). The aim was also to correlate these variables to sex and age, duration of the symptoms, diagnosis and dentition. The material consisted of 33 patients (26 women, 7 men, mean age 37 years, range 14-74 years) whose TMJs were examined by CT and whose coronal CT scans were available. Diagnosis in the symptomatic TMJ was confirmed in operation. No statistically significant difference was seen in mean densities and sizes of the masticatory muscles between the symptomatic and asymptomatic side. The duration of the symptoms, however, correlated positively to the density of the lateral pterygoid muscles in patients with complete dentition. The age of the patients in this group correlated negatively to the size of the masseter muscles. It can be concluded that patients with internal derangements of TMJ with a long duration of symptoms have structural changes in their masticatory muscles which are detectable by CT.

A 10-year follow-up study of fixed metal ceramic prosthodontics.

The aim of this retrospective study was to record patients' satisfaction with fixed metal ceramic bridges and crowns made by dental students and to evaluate the functioning and condition of the bridges and crowns clinically and radiologically. Out of the 60 patients treated at the Institute of Dentistry during 1984-85, 30 patients attended the follow-up examination (16 women, mean age 39, range 23-62 years and 14 men, mean age 44, range 26-65 years). The anamnestic data and data regarding treatment procedures were collected from the patient files. The patients had been supplied with 41 crowns and 24 bridges (mean 3.9 units, range 3-6 units), which included 61 abutments and 33 pontics or cantilever extensions (abutment/pontic ratio 1.85: 1). Marginal fidelity was unsatisfactory in 13% of the crowns and bridges and gingival bleeding and pockets of 4-6 mm were noted in 27% and 12% of cases, respectively. None of the subjects had caries in the abutments.

Changes in electrical activity of masseter and temporal muscles after temporomandibular joint surgery. A one-year follow up.

The functioning of the masseter and anterior temporal muscles was recorded by electromyography (EMG) in 15 patients with disc interference of the temporomandibular joints, before surgery and three months, six months and one year afterwards. EMG recordings were made during maximal bite in intercuspal position and while chewing. The mean electrical activity in the masseter and anterior temporal muscles, both on the operated and nonoperated sides, decreased markedly three months after surgery, especially during maximal bite in intercuspal position, but increased to above the preoperative values at the one-year recording in both functions. Statistically, significantly lower activities were seen on the operated side in patients with anterior dislocation of the disc without reduction, as compared to patients with reduction of the disc. The EMG activities of the masseter muscles on the nonoperated side were significantly lower in women and in older patients, as well as in patients with a longer duration of symptoms than in men and younger patients.

Gonial angles and condylar and ramus height of the mandible in complete denture wearers--a panoramic radiograph study.

It has been accepted that the shape of the mandibular base, and especially the gonial angle of the mandible, correlates with the function of the jaw closing muscles. The gonial angles of the mandible and condylar and ramus heights of 30 complete denture wearers (18 women, 12 men, mean age 61 years, range 42-74 years) coming for renewal of their dentures were measured using panoramic radiographs. The mean period of edentulousness was 26 years (range 10-53 years). No statistically significant difference was observed between the sexes in the the sizes of gonial angles and condylar and ramus heights. The right gonial angle was statistically significantly smaller than the left one and correlated negatively with the ramus height in both sides but positively with the increased EMG activity in the right masseter muscle. The size of the gonial angle and the condylar and ramus heights did not correlate with the age of the patients, edentulous period or alveolar ridge resorption.