Tongue function and its influence on masticatory performance in patients treated for oral cancer: a five-year prospective study.

PURPOSE: The purpose of this study was to observe the impact of oral oncological treatment, including the recovery of several tongue functions (force, mobility, and sensory functions), and to determine the influence of these functions on masticatory performance. MATERIALS AND METHODS: Masticatory performance and tongue force, mobility, and sensory functions were determined in 123 patients with oral cavity cancer. The assessments were performed 4 weeks before treatment and 4 to 6 weeks, 6 months, 1 year, and 5 years after treatment. Generalized estimation equations and mixed model analyses were performed, correcting for previously identified factors in the same population. RESULTS: A significant deterioration in tongue mobility and sensory function was observed in patients with mandible and tongue and/or floor-of-mouth tumors. Better tongue force and sensory function (thermal and tactile) positively influenced masticatory performance, and this effect was stronger where fewer occlusal units were present. The effect of both the tongue force and maximum bite force was weaker in dentate patients in comparison with patients with full dentures. A web-based application was developed to enable readers to explore our results and provide insight into the coherence between the found factors in the mixed model. CONCLUSIONS: Tongue function deteriorates after oral oncological treatment, without statistically significant recovery. Adequate bite and tongue forces are especially important for patients with a poor prosthetic state. Patients with sensory tongue function deficits especially benefit from the presence of more occluding pairs.

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.

Functional benefits of implants placed during ablative surgery: A 5-year prospective study on the prosthodontic rehabilitation of 56 edentulous oral cancer patients.

BACKGROUND: The timing of placement as well as the functional benefit of interforaminal implants in edentulous patients treated for oral cancer is unclear. METHODS: Fifty-six patients were recruited at 2 institutions. In 1 institution, interforaminal implants were placed during ablative surgery, the other institution used conventional prosthodontics with optional placement of implants postsurgery (postponed-placement). Masticatory performance, bite force, and subjective masticatory function were assessed before and 6 months, 1 year, and 5 years after surgery. RESULTS: Implant-retained overdentures (IODs) demonstrated the highest bite force and the least problems with solid food and food choice. Masticatory performance was equal for IODs and conventional dentures. After 5 years, IODs from patients in the during-ablative-surgery cohort tend to have higher bite force and masticatory performance than those from patients in the postponed-placement cohort. CONCLUSION: IODs produce the highest overall masticatory function. Implant placement during ablative surgery seems to be functionally beneficial. © 2016 Wiley Periodicals, Inc. Head Neck 38: E2103-E2111, 2016.

An Accuracy Study of Computer-Planned Implant Placement in the Augmented Maxilla Using Mucosa-Supported Surgical Templates.

PURPOSE: The purpose of this study was to determine the clinically relevant accuracy of implant placement in the augmented maxilla using computer planning and a mucosa-supported surgical template. MATERIALS AND METHODS: Twenty-five consecutive edentulous patients with an extreme maxillar alveolar ridge resorption were treated with a bone augmentation procedure. In a second stage, six Brånemark MkIII Groovy (Nobel Biocare®, Zürich, Switzerland) implants were installed. Preoperatively, a cone beam computer tomography (CBCT) scan was acquired, followed by virtual implant planning and flapless implant placement using a surgical template. A postoperative CBCT scan was acquired and registered to the preoperative scan. The Implant Position Orthogonal Projection validation method was applied to measure implant deviations in both the buccolingual and mesio-distal plane. The influence of fixation pins and the position on the dental arch were investigated with regard to implant deviations, and rotations and translations of the surgical template. RESULTS: One hundred fifty implants were installed. In mesio-distal direction, a mean implant deviation of 1.50 mm was scored at the implant tip, 1.27 mm at the shoulder, -0.60 mm in depth, as well as a mean deviation of angulation of 2.50°. In buccolingual direction, a mean implant deviation of 0.99 mm was found at the implant tip, 0.76 mm at the implant shoulder, -0.57 mm in depth, and a deviation of angulation of 2.48°. Of all implants, 53% was placed too superficial compared with the planning. The use of fixation pins and implant deviations in both buccal and mesial directions as also for rotations and translation of the surgical template showed statistically significant differences. CONCLUSIONS: Computer-aided implant planning showed to be a clinically relevant tool. However, this study emphasizes that the surgeon should take into account that deviations are larger compared with implant placement without augmentation procedure. Deviations are mainly caused by angulations and translations of the surgical template.

A clinically relevant accuracy study of computer-planned implant placement in the edentulous maxilla using mucosa-supported surgical templates.

PURPOSE: The purpose of the study is to determine the clinically relevant accuracy of implant placement in the edentulous maxilla using computer planning and a mucosa-supported surgical template. MATERIALS AND METHODS: In each of in total 30 consecutive edentulous patients suffering from retention problems of their upper denture, two or four Brånemark MkIII Groovy (Nobel Biocare®, Zürich, Switzerland) implants in the maxilla were installed. Preoperatively, first, a cone-beam computer tomography (cone beam computer tomography) scan was acquired, followed by virtual implant planning. Hereafter, a surgical template was designed to allow flapless implant placement using the template as a guide. To inventory the accuracy of implant placement, a postoperative CBCT scan was obtained and matched to the preoperative scan. The accuracy of implant placement was validated three-dimensionally. The Implant Position Orthogonal Projection validation method was applied to measure the clinically relevant implant deviations (i.e., in both the bucco-lingual and mesio-distal plane). Also, the influence of type of surgery, use of fixation pins, and position on the dental arch were investigated with regard to implant deviations. RESULTS: In total, 104 implants were installed. In bucco-lingual direction, a mean implant deviation of 0.67 mm was scored at the implant tip, of 0.51 mm at the shoulder, of -0.83 mm in depth, as also a mean deviation of angulation of 1.74°. In mesio-distal direction, a mean implant deviation of 0.75 mm was found at the implant tip, of 0.60 mm at the implant shoulder, of -0.75 mm in depth, and a deviation of angulation of 1.94°. Of all implants, 74% was placed not deep enough compared with the planning. Implant position on the dental arch, the use of fixation pins, and type of surgery showed no significant effect on implant deviations. However, a significant difference for implant deviations in both buccal and mesial direction was observed, explained by a nonoptimal positioning of the surgical template. CONCLUSIONS: Computer-aided implant planning showed to be a clinically relevant tool for the placement of two or four implants in the maxilla of fully edentulous patients. Exact positioning of the surgical template in anterior/posterior direction is crucial in reducing implant deviations both in buccal and mesial direction.

Maximum mouth opening and trismus in 143 patients treated for oral cancer: a 1-year prospective study.

BACKGROUND: Patients with oral cancer can develop restricted mouth opening (trismus) because of the oncologic treatment. METHODS: Maximum mouth opening (MMO) was measured in 143 patients shortly before treatment and 0, 6, and 12 months posttreatment, and the results were analyzed using a linear mixed-effects model. RESULTS: In every patient, MMO decreased after treatment. The patients who underwent surgery, recovered partially by 6 and 12 months after treatment, whereas the patients who received both surgery and radiotherapy or primary radiotherapy did not recover. Tumor location, tumor size, and alcohol consumption had independent effects on MMO. Having trismus (MMO <35 mm) 1 year after treatment was associated most strongly with pretreatment MMO, receiving both surgery and radiotherapy, and maxillary or mandibular tumor involvement. CONCLUSION: Postoperative radiotherapy and maxillary or mandibular tumor involvement are the highest contributing risk factors to decreasing MMO and the subsequent development of trismus after oral cancer treatment.