Masticatory function and related factors after oral oncological treatment: A 5-year prospective study.

BACKGROUND: Chewing ability is often compromised in patients with oral cancer. The aim of this study was to identify which factors affect masticatory performance in these patients. METHODS: Patients with primary oral cancer were assessed for up to 5 years after primary treatment. Healthy controls were assessed once. A mixed-model analysis was performed, with masticatory performance as outcome measure. RESULTS: A total of 123 patients were included in the study. Factors positively associated with masticatory performance were number of occlusal units (OU), having functional dentures, and maximum mouth opening (MMO). The impact of tumor location and maximum bite force (MBF) differed per assessment moment. Masticatory performance declined for up to 1 year but recovered at 5 years after treatment. CONCLUSION: Masticatory performance in patients treated for oral cancer is affected by MBF, MMO, number of OU, and dental status. These should be the focus of posttreatment therapy.

Early and late complications in the reconstructed mandible with free fibula flaps.

BACKGROUND AND OBJECTIVES: Evaluation of mandibular reconstructions with free fibula flaps. Identification of factors associated with major recipient site complications, that is, necessitating surgical intervention under general anaesthesia. METHODS: Seventy-nine reconstructions were included. The following factors were analyzed: fixation type, number of osteotomies, site of defect (bilateral/unilateral), surgeon, sex, ASA classification, continuous smoking, pathological N-stage, age, defect size, flap ischemic time, and postoperative radiotherapy. Proportional hazards regression was used to test the effect on the time between reconstruction and intervention. RESULTS: Sixty-nine (87%) of the 79 fibula flaps were successful at the last follow-up. Forty-eight major recipient site complications occurred in 41 reconstructions. Nineteen complications required surgical intervention within six weeks and were mostly vascular problems, necessitating immediate intervention. These early complications were associated with defects crossing the midline, with an estimated relative risk of 5.3 (CI 1.1-20, P = 0.01). Twenty-nine complications required surgical intervention more than 6 weeks after the reconstruction. These late complications generally occurred after months or years, and were associated with smoking, with an estimated relative risk of 2.8 (CI 1.0-8.3, P = 0.05). CONCLUSIONS: Fibula flaps crossing the midline have a higher risk of early major recipient site complications than unilateral reconstructions. Smoking increases the risk of late complications.

Tooth loss prior to radiation in relation to tumor location in patients with head and neck cancer.

PURPOSE: This study aimed to investigate the impact of preradiation tooth loss in patients with head and neck cancer. MATERIALS AND METHODS: Records of 397 (partially) dentate patients who were referred for preradiation oral screening were included. Number and location of teeth lost and occluding pairs lost were determined for different tumor locations. RESULTS: The majority of patients (54%) were affected by tooth loss. Proportion of teeth lost, their location, and proportion of occluding pairs lost were not evenly distributed across tumor locations. The highest proportions of teeth were removed with oral tumors (maxilla: 25%; mandible: 47%). For preradiation preventive extractions only, ie, not taking into account teeth that were lost due to ablative surgery, tooth loss in the mandible was still not evenly distributed across tumor locations, but tooth loss in the maxilla and occluding pairs lost were. CONCLUSIONS: Tumor location affects preradiation tooth loss, though this is primarily a consequence of ablative surgery rather than a consequence of preradiation dental extraction decisions. Since patients with oral cavity tumors are affected most by preradiation tooth loss, treatment planning with regard to functional rehabilitation is desirable for this patient group in particular.

Effects of integrated dental care on oral treatment needs in residents of nursing homes older than 70 years.

AIM: To determine effects of integrated dental care in older nursing home residents. METHODS: In three nursing homes offering integrated dental care, we studied the oral treatment need of 355 residents older than 70 years. To determine effects of integrated care, we discriminated between short-stay residents (≤6 months) and long-term residents (>6 months). RESULTS: Treatment need, determined intraorally by two dentists, remains high among short-stay residents (78%) and long-term residents (67%). The association between treatment need and length of stay was not significantly affected by indication for stay (somatic vs. psychogeriatric). All dentate residents needed oral treatment, except one long-term resident. However, among edentulous residents, particularly with a psychogeriatric indication for stay, treatment need appeared to reduce significantly in time, from 74% to 57%. CONCLUSION: Despite integrated dental care, oral treatment need remains in virtually all dentate residents and more than half of edentulous residents.

Donor-site morbidity of the radial forearm free flap versus the ulnar forearm free flap.

BACKGROUND: Donor-site morbidity following harvest of the radial forearm free flap was compared with that following harvest of the ulnar forearm free flap. METHODS: Twenty-eight radial forearm and 27 ulnar forearm flaps were harvested in 55 patients with head and neck defects. Pressure perception was measured with Semmes-Weinstein monofilaments. Cold perception was tested with chloroethyl. Donor-site healing was evaluated. Patients were interviewed about grip and pinch strength and donor-site appearance. RESULTS: In the radial forearm free flap group, pressure perception and cold perception were reduced in the donor hand, whereas in the ulnar group, no differences were observed between the donor and unoperated hands. In the radial forearm group, 15 percent of patients experienced reduced strength in the donor hand, whereas in the ulnar forearm group, none of the patients reported reduced strength in the donor hand. In the radial forearm group, 14 percent had partial or complete loss of the skin graft, whereas in the ulnar forearm group, 4 percent had partial loss of the skin graft. In the radial forearm group, 18 percent of patients were dissatisfied with the appearance of the donor site, and no complaints were reported in the ulnar forearm group. CONCLUSIONS: The authors' study shows less donor site-morbidity following harvest of the ulnar forearm free flap than following harvest of the radial forearm free flap. These results emphasize that the ulnar forearm free flap should be considered as an alternative for the radial forearm free flap for reconstruction of soft-tissue defects. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

An epidemiological study of maxillofacial fractures requiring surgical treatment at a tertiary trauma centre between 2005 and 2010.

The epidemiology of maxillofacial fractures shows considerable regional variation as a result of local demographic and socioeconomic factors. We have assessed the epidemiological characteristics of such fractures at our centre in The Netherlands. The medical records of 394 patients who were treated surgically for maxillofacial fractures between 1 January 2005 and 31 December 2010 were analysed retrospectively. The male:female ratio was 3:1. There was a peak incidence in the second and third decades of life among men. The number of injured patients/year remained stable during the selected period. The incidence was highest in the spring and at weekends. Fractures of the mandible and zygoma were the most common. Road traffic crashes were the most common cause of injury (42%) and mainly involved bicycles. A total of 165 (15%) of the patients were intoxicated, and 142 patients (36%) had other serious injuries. Most patients (n=248, 63%) were treated within a day of presentation. Two hundred and thirty-two patients (59%) spent 4 days or fewer in hospital. The presence of other injuries was associated with a prolonged stay in hospital. Groups at particular risk of maxillofacial fractures are young men and cyclists. The use of helmets by cyclists could achieve a large reduction in injuries to the brain and upper face.

The influence of auditory and visual information on the neuromuscular control of chewing crispy food.

The influence of auditory and/or visual information on the neuromuscular control of chewing a crispy food was investigated. Participants chewed biscuits of three different levels of crispness under four experimental conditions: no masking, auditory masking, visual masking, and auditory plus visual masking. The order of the four masking condition blocks was randomized. The sound of chewing was masked by loud sounds on a headphone, and visual masking of the food was achieved by closing the eyes. Mechanical tests were performed on the biscuits to determine their characteristics, yield force, and sound production. Skull vibration, jaw-muscle activity, and jaw movement were measured while the subjects chewed and swallowed the food. Auditory and/or visual masking did not have a significant effect on skull vibration, muscle activity, and number of chewing cycles until swallowing. However, auditory and/or visual masking significantly increased the chewing cycle duration, but only for the participants who started the experiments with auditory and/or visual masking. The other participants were not influenced by masking. The memory of the unmodified stimuli helped these subjects to maintain their habitual chewing rate in later trials.

Mastication in patients treated for malignancies in tongue and/or floor of mouth: A 1-year prospective study.

BACKGROUND: People confronted with oral cancer run a high risk of deteriorated masticatory performance. Reduced masticatory function may affect quality of life and food choice. An altered food choice may result in lower intakes for key nutrients and weight loss. METHODS: Dental state, bite force, and masticatory performance were determined in a group of 45 patients with squamous cell carcinoma of the tongue and/or floor of mouth. Measurements were performed before surgery and at various moments after surgery and/or radiotherapy. RESULTS: Surgical intervention had a large negative impact on oral function. Radiotherapy further worsened oral function. Also, the recovery of oral function 1 year after surgery was less prominent for the surgery-radiotherapy group than for the surgery group. CONCLUSION: Objective determination of oral function 1 year after surgery showed that patients treated for malignancies in the tongue and/or floor of mouth had significantly deteriorated masticatory performance, bite force, and dental state.

Bite force and electromyograpy during maximum unilateral and bilateral clenching.

Maximum voluntary bite force has often been studied as an indicator of the functional state of the masticatory system. Bilateral, as well as unilateral, methods have been used to determine bite force. Only a few studies have compared the outcomes of both methods. The aim of this study was to measure bite force and jaw-muscle activity during bilateral as well as unilateral maximum clenching in a large number of healthy subjects, so that the results could be compared. In a group of 81 dentate subjects we observed an average bilateral bite force of 569 N. The average unilateral bite force was significantly lower, being 430 N (right) and 429 N (left). Masseter and anterior temporal muscle activities were also significantly lower during unilateral clenching as compared with bilateral clenching. The masseter muscles showed no difference in activity between the ipsilateral side and the contralateral side during unilateral clenching. In contrast, the activity of the anterior temporal muscle on the ipsilateral side was significantly higher than on the contralateral side. Thus, the change in the forces acting on the jaw during unilateral clenching compared with bilateral clenching leads to a different response in the temporal muscles than in the masseter muscles.

Effects of adding fluids to solid foods on muscle activity and number of chewing cycles.

The production of a sufficient amount of saliva is indispensable for good chewing. In the present study, we examined the hypothesis that adding fluid to a food will facilitate the chewing process, especially for dry foods. The effect might be larger for subjects with relatively low salivary flow rates. Furthermore, adding fluids that contain mucins or alpha-amylase may have a larger facilitating effect on mastication than the addition of water alone. Twenty subjects chewed on melba toast, breakfast cake, carrot, peanut, and Gouda cheese. In addition, they chewed on these foods after different volumes of water, artificial saliva containing mucins, or a solution of alpha-amylase had been added. Muscle activity and number of chewing strokes until swallowing were measured. The salivary flow rates of the subjects were also determined. Adding fluid to the food significantly reduced the number of chewing cycles and total muscular work (i.e. the integrated surface electromyograpy of masseter and temporalis muscles measured bilaterally, summed for all chewing cycles) until swallowing for all foods, except carrot. The largest effects were observed for melba and cake, which are dry products requiring sufficient saliva to form a coherent bolus safe for swallowing. More facilitation of the chewing process was observed after adding fluid to breakfast cake for subjects with relatively low salivary flow rates. The type of fluid had no significant effect on the chewing process.

Functional roles of oral reflexes in chewing and biting: phase-, task- and site-dependent reflex sensitivity.

Because loading during chewing is not totally predictable and jaw-closing muscles are strong and act over short distances, feedback from oral receptors is important in the control of mastication. Information on such feedback can be obtained by studying reflexes in jaw muscle EMGs. This review will deal with the contribution of reflex mechanisms to modifying motor neuron activity during chewing, and the dependency of reflex sensitivity on motor task, phase of movement, and site of stimulation.