1.
Relationship between functional masticatory units and cognitive impairment in elderly persons.
Cardoso, MG, Diniz-Freitas, M, Vázquez, P, Cerqueiro, S, Diz, P, Limeres, J
Journal of oral rehabilitation. 2019;(5):417-423
Abstract
BACKGROUND Studies on the elderly have reported that the risk of cognitive impairment is affected by chewing difficulty. OBJECTIVE To determine whether there is a relationship between the number of pairs of antagonist teeth that come into contact when the mouth is closed (functional masticatory units [FMUs]) and the level of cognitive impairment. METHODS We conducted a cross-sectional observational study with 502 institutionalised White individuals older than 65 years, living in the northwest of Spain and Portugal. Through a direct visual inspection, we recorded the number of FMUs. Cognitive impairment was assessed by applying the Mini-Cognitive Examination (MCE), a test derived from the Mini-Mental State Examination. To describe the statistical relationship between the FMUs and the MCE values, a generalised linear model (GLM) was applied. We assessed the GLM predictive capacity for detecting cognitive impairment (MCE ≤23) in a new study group consisting of 156 elderly individuals. RESULTS A large number of FMUs was significantly associated with a lower probability of cognitive impairment, regardless of the nature of the contact and its location (explained deviance, 30.1%). The model's discriminatory capacity for cognitive impairment based on the FMUs was "good" (0.820). The model's predictive capacity for cognitive impairment was "acceptable" (sensitivity, 0.786; positive predictive value, 0.900; accuracy, 0.729). CONCLUSION In White, elderly institutionalised individuals, the absolute number of FMUs is significantly related to their MCE scores.
2.
Prospective evaluation of relationships between radiotherapy dose to masticatory apparatus and trismus.
Hague, C, Beasley, W, Garcez, K, Lee, LW, McPartlin, A, McWilliam, A, Ryder, D, Sykes, AJ, Thomson, D, van Herk, M, et al
Acta oncologica (Stockholm, Sweden). 2018;(8):1038-1042
Abstract
AIMS: This feasibility study aimed to identify relationships between radiation doses to the masticatory apparatus as a combined block or as individual subunits with changes in trismus following radiotherapy. MATERIAL AND METHODS Twenty patients from a single center were recruited prospectively as part of a randomized trial comparing proactive exercises in the management of trismus. Patients with stage III/IV oral cavity or oropharyngeal squamous cell cancers received intensity-modulated radiotherapy with concurrent systemic therapy. All patients had trismus prior to radiotherapy. Maximal inter-incisor distance (MID) was measured pre- and 6 months from the start of radiotherapy. Bilateral muscles of mastication: medial and lateral pterygoids (MP and LP), masseters (M), temporalis (T), temporomandibular joint (TMJ) were contoured on CT images. The block comprised all muscles excluding the TMJ below the orbital floor. Mean dose, equivalent uniform dose (EUD) and V35-V60 Gy were compared with change in MID. RESULTS In six patients, the MID deteriorated at 6 months from the start of radiotherapy compared with 14 whose MID improved. No significant association was observed between age, gender, smoking, alcohol status, exercise compliance, cisplatin, tumor site, stage, V35-V60 Gy or EUD with change in MID. A clinical outlier was excluded. Without the outlier (n = 19), a significant association was seen between mean dose and change in MID at 6 months for the ipsilateral block (p = .01), LP (p = .04) and M (p < .01). All patients where trismus deteriorated at 6 months received mean doses >40 Gy to the block. CONCLUSION Higher mean radiation doses to the ipsilateral block, LP and M were significantly associated with deterioration in trismus. Limiting dose to these structures to ≤40 Gy for tumors not invading the masticatory muscles may improve treatment-related sequelae. The ipsilateral block, LP and M should be studied further as possible alternative avoidance structures in radiotherapy treatment planning.
3.
Single mandibular implant study (SMIS) - masticatory performance - results from a randomized clinical trial using two different loading protocols.
Passia, N, Abou-Ayash, S, Reissmann, DR, Fritzer, E, Kappel, S, Konstantinidis, I, Königsmarck, VV, Mundt, T, Stiesch, M, Wolfart, S, et al
Journal of dentistry. 2017;:64-69
Abstract
OBJECTIVES This multi-centre randomized controlled trial was conducted to investigate, whether the masticatory performance of elderly edentulous patients is improved by placement of a single implant in the midline of the edentulous mandible, and whether improvements differ with respect to the loading protocol, i.e., implant is loaded either directly or three months later after second stage surgery. METHODS Edentulous seniors aged 60-89 years were screened according to inclusion and exclusion criteria and 163 underwent implant placement. Of those, 158 were randomly assigned either to the direct loading group A (n=81) or the conventional loading group B (n=77). Chewing efficacy was obtained before treatment, one month after implant placement during the submerged healing phase (only group B) and 1 and 4 months after implant loading. RESULTS The masticatory performance increased over time in both groups. Four months after loading, a significant increase was observed for both groups compared to the baseline data without implant (p≤0.05). However, between the two groups, chewing efficiency did not differ significantly at any point in time (p>0.05). CONCLUSIONS A single midline implant in the edentulous mandible increases masticatory performance significantly, independently from the loading protocol. CLINICAL SIGNIFICANCE A single midline implant in the edentulous mandible increases masticatory performance. The loading protocol has no influence.