This study was approved by the Institutional Review Board of Bauru School of Dentistry (CAAE: 59800016.3.0000.5417). This study confirm that all experiments in accordance with relevant guidelines and regulations and was have been performed in accordance with the Declaration of Helsinki.
The sample calculation considered a significance level of 5% and sample power of 80% for the Spearman correlation, obtaining n=29 of adult individuals, both males and females, after surgical treatment, radiotherapy and/or chemotherapy for head and neck cancer. The study participants received dental treatment at the Clinical Research Center (CPC) of Bauru School of Dentistry, where the 29 individuals who met the inclusion criteria were invited, yet 9 participants were lost, either due to refusal to participate in the study, cancer relapse, lack of phone answer or death.
Thus, the study sample consisted of 20 adult and elderly individuals, aged 30 to 63 years, with mean age 53.2 years. The characteristics regarding gender, age, medical diagnosis and information about the treatments performed are presented in Table 1. All participants were clearly informed about the research procedures and signed an Informed Consent Form.
The following inclusion criteria were adopted: accomplishment of treatment for oral, oropharyngeal, pharyngeal or laryngeal cancer at least three months earlier, including radiotherapy, chemotherapy and/or surgery, combined or not, as well as exclusive oral diet.
Patients with a history of neurological disease or syndromes, undergoing treatment for cancer in any site, using tracheostomy and/or wheelchair were excluded, the latter because the calculations to measure weight and height applied to wheelchair users are different from those proposed for this study.
Table 1 – Individual data of the sample concerning gender, mean age, cancer site, period after treatment, site of treatment and type of RT
Patient
|
Gender
|
Age (years)
|
Cancer site
|
Patient
|
Treatment
|
Period after treatment
|
Site of treatment
|
Type of RT
|
modality
|
1
|
F
|
46
|
Upper lip
|
1
|
CR + RT
|
13 months
|
Upper lip
|
IMRT
|
2
|
M
|
44
|
Nasopharynx
|
2
|
RT
|
8 months
|
Cervical region
|
IMRT
|
3
|
M
|
56
|
Larynx
|
3
|
CT + RT
|
64 months
|
Head and Cervical region
|
IMRT
|
4
|
M
|
51
|
Tongue base
|
4
|
CR
|
22 months
|
-
|
-
|
5
|
M
|
54
|
Tongue base and border
|
5
|
CR + CT + RT
|
53 months
|
Tongue
|
IMRT
|
6
|
M
|
48
|
Left tonsil
|
6
|
CT + RT
|
44 months
|
Cervical region
|
IMRT
|
7
|
M
|
41
|
Oropharyngeal
|
7
|
CT + RT
|
5 months
|
Cervical region
|
IMRT
|
8
|
M
|
49
|
Mouth floor
|
8
|
CR
|
31 months
|
-
|
-
|
9
|
M
|
58
|
Epiglottis
|
9
|
CR + CT + RT
|
12 months
|
Cervical region
|
IMRT
|
10
|
M
|
58
|
Oropharyngeal
|
10
|
CT + RT
|
6 months
|
Cervical region
|
IMRT
|
11
|
F
|
48
|
Left oral mucosa
|
11
|
CR + RT
|
4 months
|
Cervical region
|
IMRT
|
12
|
M
|
30
|
Soft palate
|
12
|
CR + CT + RT
|
3 months
|
Cervical region
|
IMRT
|
13
|
M
|
60
|
Tongue base and tonsil pillar
|
13
|
CR + CT + RT
|
32 months
|
Head and Cervical region
|
IMRT
|
14
|
M
|
62
|
Soft palate
|
14
|
CT + RT
|
14 months
|
Cervical region
|
IMRT
|
15
|
M
|
61
|
Tongue base
|
15
|
CT + RT
|
10 months
|
Cervical region
|
IMRT
|
16
|
M
|
61
|
Larynx
|
16
|
CT + RT
|
6 months
|
Cervical region
|
IMRT
|
17
|
M
|
59
|
Tongue (right border)
|
17
|
CR
|
17 months
|
-
|
-
|
18
|
M
|
63
|
Tongue base
|
18
|
CT+RT+CR
|
13 months
|
Cervical region
|
IMRT
|
19
|
F
|
62
|
Oropharyngeal
|
19
|
CT+RT+CR
|
36 months
|
Cervical region
|
IMRT
|
20
|
F
|
53
|
Nasopharynx
|
20
|
CR+RT+CT
|
42 months
|
Cervical facial
|
Cobalt therapy
|
n=20
|
F - 4
|
Mean=53.2
|
|
|
|
|
|
|
M - 16
|
|
|
|
|
Descriptive analysis
Legend: M=male; F=female; E=left; n=number; RT=radiotherapy; CT=chemotherapy; CR=Surgery; IMRT: Intensity-Modulated Radiotherapy
Electromyographic evaluation of masticatory function
The electromyographic activity was recorded on an eight-channel electromyography equipment BTS FREEMG 300 (BTS Bioengineering Ltda). In preparation for the assessment, the individuals were seated on a fixed chair, with their feet touching the floor. Then, the skin was cleaned with 70% alcohol and gauze to reduce the impedance and bipolar silver chloride surface double electrodes (10-mm diameter, inter-electrode distance 21±1 mm) were positioned parallel to the fibers of masseter and anterior temporalis muscles on both sides.
The exams selected to record the electromyographic activity were Maximum Voluntary Contraction (MVC), performed at two moments as described by Felício et al20 and Tartaglia et al21.
The analysis also considered the mean of potentials evaluated in the 3 most constant seconds of MVC with cotton rolls as 100%, and the potentials obtained during chewing were expressed as a percentage of these values.22
Then, a bivariate and simultaneous analysis of the differential activity of masseter and temporalis muscles was performed, with representation on the Cartesian axes by the Lissajousplot, in which the x coordinate represented the differential activity of the right-left masseter, and the y coordinate referred to the differential activity of the right-left temporalis. Thus, the following electromyographic indices were obtained:18,21,22 Total Impact (%s); Impact per cycle (%s); Confidence Ellipse (%2); Mean Module (%); Phase (°); Chewing symmetry (%); Work and Balance (%); Chewing frequency (Hz).
Evaluation of oral health
The oral status was assessed by analysis of the DMFT index, community periodontal index (CPI) and evaluation of the use and need of dentures. The patients were examined by a trained and calibrated dental professional.
Caries activity (DMFT): The DMFT index quantifies the caries activity by the mean of the total number of permanent decayed (D), missing (M) and filled (F) teeth. This examination was performed under artificial light, using a spatula for tissue retraction, dental mirror and a blunt-tip probe.
The tooth was considered as "decayed" if there was cavity, opacity along the surfaces or stain; "missing", if extracted or indicated for extraction; "filling", for teeth with amalgam or composite restorations or similar; and "absent", unerupted tooth or hypodontia.
Patients presenting caries or active white spot lesions were recorded as need for treatment. The codes and criteria for the dental status were performed according to the WHO guidelines.23
The DMFT was calculated by adding the codes, thus it was calculated by dividing the sum of individual DMFTs by the number of patients, thus obtaining the classification of caries activity, namely 0-1.1 (Very low); 1.2-2.6 (Low); 2.7-4.4 (Average); 4.5-6.5 (High) and ≥ 6.6 (Very High).23
Community Periodontal Index (CPI): The periodontal health was assessed using a blunt-tip periodontal probe, dental mirror and disposable tongue depressor, under artificial light. The probe was introduced in the gingival sulcus or periodontal pocket, inclined in relation to the tooth long axis, following the anatomical configuration of the root surface, with probing force lighter than 20g. Probing was initiated on the distobuccal area, moving to the central area and then to the mesiobuccal area. Thereafter, the lingual, distal and mesial areas were examined.24 The codes and criteria for the CPI followed the WHO guidelines.23
Use and need of dentures/edentulism: The evaluation of edentulism followed the WHO guidelines for epidemiological surveys. The type and location of dentures were considered, either lower or upper, according to the prosthetic spaces corresponding to the missing teeth observed on the physical examination, thus being classified according to the WHO codes and criteria.23
Oral health-related quality of life
The study applied the Oral Health Impact Profile (OHIP-14), a short version of OHIP-49, containing 14 questions divided into 7 dimensions (functional limitation, physical pain, psychological discomfort, physical limitation, psychological limitation, social limitation and disability), and its application individually demonstrated the perception of individuals about the impact of their oral conditions on the quality of life.25
The instrument was applied as an interview, and the participants were asked to respond according to their perception about their oral problems in the last twelve months.26 A card with printed questionnaire responses was presented, aiming to ensure the understanding of possibilities of responses by the patient.
The final analysis was performed as described by Slade.25
Anthropometric evaluation of nutritional status
Arm Circumference: The arm circumference (AC) represents the sum of the areas composed of bone, muscle and fat tissues of the arm.11
Skinfold thickness: The skinfold thickness was expressed by the amount of body fat tissue, which may indicate the body energy reserves and the current nutritional status.11 This included: tricipital skinfold thickness (TST); bicipital skinfold thickness (BST); subscapular skinfold thickness (SSST); supra-iliac skinfold thickness (SIST). From the measurement of skinfold thickness, the individuals were scored according to their fat reserves.
Muscle circumference of the arm (MCA): This parameter assesses the muscle tissue reserve (without correction of bone area). It is obtained from the values of AC and TST. The MCA adequacy was calculated based on the MCA value.27
Percentage of body fat: After measurements of skinfold thicknesses TST, BST, SIST and SSST, the sum was obtained (∑ 4PC) and the body density was calculated as suggested by Durnin and Womersley.28 The body density was converted into percentage of body fat by the equation of Siri29 following the classification from very low to very high.30
Body mass index (BMI): The weight and height measurements were used to calculate the BMI by dividing the body weight (Kg) by the height (m2). The values found were compared with the standards suggested by the World Health Organization (WHO) for adults, and for individuals older than 60 years as suggested by Lipschitz31.
Statistical analysis
The results of masticatory function, nutritional assessment, oral health and oral health-related quality of life were described by absolute and relative frequencies (n), and also by means and standard deviations.
The correlations of quantitative variables were calculated by the Pearson Correlation Coefficient, while the Spearman Correlation Coefficient was used for qualitative variables. All statistical tests were performed at a significance level of 5% (p<0.05).
For correlations, the classifications were determined according to the r value, namely weak from 0.10 to 0.30, moderate from 0.40 to 0.60, and strong from 0.70 to 1.0.32