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.

A comparative study on four screw-plate locking systems in sheep: a clinical and radiological study.

Four mandibular screw-plate locking systems were studied in sheep. Three to four centimetres angular continuity resections of the mandible were performed and the defects bridged with pre-bent angular reconstruction plates fixed with four screws in the body part and three in the ramus. Each type was used four times. Clinical and radiological examinations were carried out 1 and 2 months later. All sheep were able to eat and ruminate normally throughout the postoperative period. Radiology revealed that 6/16 plates and 5/112 screws fractured during the follow-up period. In one type, no fracture occurred. Screw fracture was confined to just one reconstruction system. Six of 16 mandibles showed slight to moderate bone resorption under the plate. The results point to the internal shortcomings of the systems tested.

A 12 country field study of the EORTC QLQ-C30 (version 3.0) and the head and neck cancer specific module (EORTC QLQ-H&N35) in head and neck patients. EORTC Quality of Life Group.

This study tests the reliability and validity of the European Organization for Research and Treatment of Cancer (EORTC) head and neck cancer module (QLQ-H&N35) and version 3.0 of the EORTC Core Questionnaire (QLQ-C30) in 622 head and neck cancer patients from 12 countries. The patients completed the QLQ-C30, the QLQ-H&N35 and a debriefing questionnaire before antineoplastic treatment or at a follow-up. 232 patients receiving treatment completed a second questionnaire after treatment. Compliance was high and the questionnaire was well accepted by the patients. Multitrait scaling analysis confirmed the proposed scale structure of the QLQ-H&N35. The QLQ-H&N35 was responsive to differences between disease status, site and patients with different Karnofsky performance status, and to changes over time. The new physical functioning scale (with a four-point response format) of version 3.0 of the QLQ-C30 was shown to be more reliable than previous versions. Thus, the QLQ-H&N35, in conjunction with the QLQ-C30, appears to be reliable, valid and applicable to broad multicultural samples of head and neck cancer patients.

Fixation with reconstruction plates under critical conditions: the role of screw characteristics.

Mandibular angular ostectomy defects in 12 sheep were bridged with a titanium plate system (THORP), designed according to the screw-plate-locking principle. Two screw designs (hollow and solid) and two rough (plasma-coated, sand-blasted)-surface and one smooth (anodized)-surface structure were tested in a critical two-screw anchorage model. Fixation with two screws only per fragment was successful in only one-third of the cases. The fixation results were superior for screws with a rough surface, either sand-blasted or plasma-coated. The hollow-screw design did not seem to offer special advantages over the solid screws with identical surface structure. In the successful cases, the bone-screw contact was maintained continuously over a period of 8 weeks, and anchorage was even enhanced by reinforcement of the cancellous structures. In the unsuccessful cases, peri-implant bone resorption seemed to be related to jeopardized bone perfusion in the vicinity of the implants. It is presumed that a plating system with locked screws has the advantage that only two screws will hold a relatively short condylar process. This study proved the assumption to be questionable. However, in view of the problems related to prosthetic replacement of the temporomandibular joint, an attempt to salvage the articular portion may still be justified in selected cases, even if the chance of success is as low as 30%.

Lag-screw osteosynthesis of mandibular condyle fractures: a clinical and radiological study.

PURPOSE: This study evaluates the clinical and radiologic results after open reduction and lag-screw osteosynthesis of fractured mandibular condyles. MATERIALS AND METHODS: Eleven adult patients underwent surgery for displaced or dislocated mandibular condyle fractures via a submandibular approach. The repositioned fragments were fixed using lag screws designed by Krenkel or Eckelt. Maxillomandibular fixation was used postoperatively for 2.6 weeks on average (range, 1 to 4 weeks) in nine patients. RESULTS: Slight transient weakness of the mandibular branch of the facial nerve occurred in three cases. Occlusal adjustment was needed in another three cases. Radiologically, the fracture line disappeared at 22.5 weeks on average (range, 8 to 38 weeks). Three screws had to be removed because of loosening. There were signs that the screws had migrated caudally from their original position in seven cases. Twenty-one months on average after operation (range, 8 to 31 months), patients were satisfied with treatment. Clinically, all patients had a stable occlusion and symmetry of the face. All had greater than 5-mm symmetrical lateral jaw excursions. Ten patients had wide (> 40 mm) painless mouth opening. Healing in malposition occurred in four cases and there was considerable shortening of the mandibular ramus in four cases. CONCLUSIONS: Despite good clinical results, lag screws do not meet the needs for rigid internal fixation in the treatment of mandibular condyle fractures.

Neuromuscular dysfunction after surgical treatment of oral cancer.

Surgical treatment of oral cancer usually includes radical dissection of the neck, in which the sternocleidomastoid muscle is sacrificed. In modified neck dissection the accessory nerve is spared, but may be severed by e.g. manipulation. The facial nerve may also be severed by traction or distension. We have done an electromyographic study of 35 patients, 20 men and 15 women, aged from 21 to 92 yrs, 6 to 176 months after oral cancer operation. EMG findings of the upper trapezius muscle were normal in only six of 32 patients who had had a radical or upper neck dissection, although the accessory nerve had been identified and spared during surgery. The surgeons' evaluation of the risk to the facial nerve was in good correlation to EMG findings, both the orbicularis oris and the mentalis muscle were better preserved, if the risk was considered minor. The loss of motor units in voluntary contraction and the nerve latencies to the muscles were in good correlation to many factors from the spectral analysis of the EMG, e.g. to the root mean square (RMS), to the mean rectified value (MRV), to the mean amplitude and to the number of turns. The accessory nerve is easily damaged, and the injury is often not noted during neck dissection. Significant problems may also arise with lesions of the facial nerve. Quantitative EMG analysis may add to sensitivity of the postoperative EMG studies.

Cancers of the lip and oropharynx in different social and occupational groups in Finland.

Social status and occupation-specific risks of cancers of the lip, tongue, mouth and pharynx were studied in a nationwide series of 2369 men and 809 women diagnosed in Finland in 1971-1985 and recorded in the files of the Finnish Cancer Registry. Codes for social status (four classes) and occupation (336 categories) were drawn from the files of the 1970 Population Census. The standardised incidence rates (SIR) were defined as the ratios of observed and expected numbers of cases, the expected ones being based on the sex, age, site and calendar period-specific incidence rates in the Finnish population. The SIR of lip cancer in the lowest social class was five times that of the highest one, thus indicating the effects of social class differences in smoking habits. The effect of outdoor work on the development of lip cancer was also strongly supported by this study. The social class-adjusted SIR for fisherman was 2.7 (95% C.I. 1.3-5.0), for forestry managers 2.2 (1.2-3.6), for timber workers 1.9 (1.2-2.9) and for farmers 1.8 (1.2-2.6). For cancers of the oral cavity and pharynx there was no clear correlation with social class. However, the SIR for these cancers among farmers was significantly reduced. The occupation-specific SIRs pointed more to alcohol than smoking aetiology. In the case of cancer of the tongue, no aetiological clues whatsoever could be found. The role of direct occupational factors in the aetiology of any of these cancers seemed to be minimal.

Risk of new primary cancer in patients with oropharyngeal cancer.

The relative risk of subsequent cancers was evaluated for a total of 9,092 patients with lip and oropharyngeal cancer recorded between 1953 and 1989 in the nationwide Finnish Cancer Registry. The observed numbers of patients were compared with those expected on the basis of the incidence rates in the Finnish population. There were 1,130 patients (12%) with a new cancer. The standardised incidence ratio (SIR) of contracting a new primary cancer was 1.2 for lip cancer patients (95% CI 1.1-1.3) and 1.4 for patients with oropharyngeal cancer (95% CI 1.2-1.4). Among lip cancer patients, a statistically significant excess risk was found for subsequent cancers in the oropharyngeal area (SIR 1.9, 95% CI 1.1-3.1), larynx (SIR 2.0, 95% CI 1.2-2.9) and lung (SIR 1.4, 95% CI 1.3-1.6), i.e. for cancers with tobacco aetiology. Among patients with oropharyngeal cancer there was an excess of lip cancer (SIR, 3.5, 95% CI 1.5-6.9), lung cancer (SIR 1.8, 95% CI 1.3-2.3) and leukaemia (SIR 2.3, 95% CI 1.0-4.3). Radiotherapy for the first primary did not increase the risk of new cancer.

Long-term stability of two different mandibular bridging systems.

To evaluate the benefits of narrow-beam roentgenography and spiral tomography for examination and monitoring of screw and plate fixation to bone we studied 22 rigid plate bridgings of mandibular defects. The plate reconstructions were of long duration or considered permanent. In 13 patients, AO-THORP (AO: Arbeitsgemeinschaft für Osteosynthesefragen; THORP: Titanplasma-beschichteten Hohl- und Vollkern-Rekonstruktionsplatten-Systems) reconstructions were used and in nine classic AO stainless steel plate bridgings. With the AO-THORP system, good bone apposition to the screws was evident in 96% (73/76 screws) of the cases. Fixation using the classic AO screws, however, was inadequate in 30% (20/66 screws) of the cases. Plate loosening was noted in 56% (5/9 plates). Examination using narrow-beam roentgenography and spiral tomography provided detailed information about bone resorption around the screws and provided a reliable tool for deciding on a follow-up regimen. When complications occur, they can be detected and treated early, reducing patient morbidity. In our opinion, classic AO plate bridging should always be considered temporary.

Third molars confusing the diagnosis of carcinoma.

The purpose of this study was to describe cases of oral cancer in which the initial presenting symptoms were considered to be due to third molars and in which the underlying carcinoma therefore escaped early diagnosis. Between 1986 and 1990 a total of five cases with squamous cell carcinoma associated with a third molar (impacted, partially or totally erupted, or recently extracted) were treated at our unit. Because of acute or chronic symptoms related to disturbed eruption of third molars, the detection of a simultaneous malignant change and referral were delayed. In conclusion, all third molars, especially impacted, partially erupted, or overerupted ones, should be examined critically, especially if the patient has symptoms.

Rigid reconstruction plates for immediate reconstruction following mandibular resection for malignant tumors.

Thirty-four primary alloplastic reconstructions of segmental mandibular defects caused by surgery for oral malignancy were performed during a 6-year period. Eighty-eight percent of the tumors were classified as stage III or IV. One third of the patients died during follow-up, nine with their primary reconstruction plate in place. During the follow-up, 12 patients required plate removal because of complications; four of them were treated with another plate. Nineteen of 21 patients alive at the end of follow-up were free of disease. Ten had their primary plate in place, and four had had a secondary plate installed because of plate fracture or screw loosening. Three patients had their mandible permanently reconstructed with bone. The functional and esthetic results were considered excellent or fair in a majority of the cases. Because the 5-year survival rate for patients with advanced mandibular malignancies is 15% to 20%, extensive, definitive reconstructive procedures during primary surgery are usually not justified.

Erosion and heterotopic bone formation after alloplastic temporomandibular joint reconstruction.

Twenty-three temporomandibular joint arthroplasties using metallic condylar prostheses were performed because of severe ankylosis (8 patients), segmental mandibular resections in tumor surgery (9 patients), and after extensive trauma (2 patients). A clinical and radiological follow-up study showed heterotopic bone formation in 52% of cases and glenoid fossa resorption in 43%. In one patient with rheumatoid arthritis the condyle eroded through the skull base 10 months after surgery. Seven prostheses (30%) were removed and/or exchanged during the average 27.6-month follow-up.

Tumour markers and radiological examinations in the follow-up of patients with oral cancer.

In 1986, a new follow-up programme for patients with oral cancer was introduced in our department. The follow-up programme included liver function tests, tumour markers and radiological examination. 63 patients were monitored to the end of 1990. The results showed that serum Carcinoembryonic Antigen (CEA) assays were not sensitive enough to detect early cancer, recurrences or metastases. Neither was there any difference between the preoperative CEA levels of patients with and without recurrence during follow-up. The levels of salivary CEA, were similar to those of healthy individuals. Serum CA 19-9 values were consistently normal. In 1 patient, the first sign of liver metastases was a high 5-nucleotidase level. No recurrences were detected by radiological examination. In conclusion, the importance of frequent and careful clinical observation is emphasized; all 20 recurrences at the primary site and in local lymphnodes were detected by clinical examination. For detection of oral cancer recurrences, several laboratory and radiological examinations seem unnecessary. The cost-benefit of those examinations is significantly low.

Is nasotracheal intubation safe in surgery for mandibular cancer?

A retrospective study of problems of postoperative airway maintenance after surgery for mandibular cancers was conducted. Twenty-seven patients treated in an intensive care unit after mandibular resection and primary reconstruction were included. The mean duration of nasotracheal intubation in 22 patients was 33.7 hours. Reintubation because of breathing difficulties was required in four cases. In one of these cases, failed intubation led to an emergency cricothyroidostomy. Failure to perform reintubation resulted in the death of one patient. One patient was tracheostomized after 5 days of nasotracheal intubation. Prolonged nasotracheal intubation after major surgery for oral malignant neoplasms may be an alternative to tracheostomy, provided that adequate monitoring is available after extubation. The safe duration of endotracheal intubation is difficult to determine. Primary reconstruction does not eliminate the need for an artificial airway after tumor surgery.

Radiologic follow-up of bone transplants to bridge mandibular continuity defects.

Special radiologic imaging techniques were used to evaluate the results of nonvascularized bone grafts combined with rigid mandibular reconstruction plates. The radiologic findings divided 21 cases into three clearly distinct groups on the basis of resorption: slight (less than 15%), moderate (15% to 30%), and massive (more than 30%) (mean follow-up, 26 months). This division predicted the clinical results well. In contrast to earlier reports, it was shown that rigid plate bridging did not adversely influence the prognosis of the graft. Nor was early plate removal necessary to reach good ossification. Narrow-beam radiography and spiral tomography proved to be excellent tools for adequate evaluation of bone resorption and bony healing of mandibular grafts.

The histologic pattern of bone invasion by squamous cell carcinoma of the mandibular region.

Surgical specimens from 16 nonirradiated patients with carcinoma of the mandibular region who had undergone resection of the mandible were investigated histologically to evaluate the presence, pattern and extent of bone involvement. Thirteen of the 16 carcinomas had invaded the mandibular bone. Two main patterns of growth were identified: seven carcinomas had infiltrated nonuniformly into the bone and six tumours had advanced as a compact front. Direct invasion from the oral mucosal tumour could be verified in 12 cases. Extension of four of these 12 tumours in bone clearly exceeded their dimension in the overlying mucosa. Carcinoma tissue in the mandibular canal, at a distance from the major tumour extension, was seen in two cases, whereas the periodontal ligament spaces were invaded only when there was a direct contiguous invasion by the tumour. The grade of histologic differentiation of the carcinoma did not definitely correlate with the frequency, pattern or extension of bone involvement. The results indicate that large tumour size, location on the mandibular alveolar ridge and clinical fixation to the mandibular bone predispose to, but are not prerequisites for bone invasion. Taken together, this study has shown that prediction of the presence and extent of bone involvement of the carcinoma located in the mandibular region is difficult on clinical grounds.