Table 3: Descriptive characteristics of the reviewed articles based on PICO structure.

Author, year	Population, problem, patient (P)	Intervention (I)	Comparison (C)	Outcomes (O)
Ribeiro, et al. [4]	N = 17 patients were with PD (mean age 69.4 ± 4.7 years).	OHRQoL and ME evaluations before and two months after wearing removable dentures.	The control group consisted of 17 elders (10 men and 7 women; mean age 70.7 ± 4.7 years).	1. Controls showed an improvement in ME after insertion of the removable prosthesis. 2. ME was also lower for elders with PD when compared with controls at baseline. 3. After the insertion of removable prostheses, those with PD showed a 76.1% decrease in total OHIP-49 scores (P < 0.05).
Ribeiro, et al. [5]	N = 17 patients, with PD, (mean age = 69.41 ± 4.65 years).	A kinesiographic device usage to measure the range of jaw motion and movements, while chewing a silicone test material (Optocal). Masticatory performances and maximum biting forces evaluation.	The control group consisted of 17 patients without PD, (mean age = 70.71 ± 4.65 years).	1. In PD group: Decreased range of jaw motions, longer duration and slower velocity of the masticatory cycle (P < 0.05), increased masticatory performance and lower maximum bite force (P < 0.05). 2. No group differences were observed in opening and closing angles (P > 0.05).
Kaka, et al. [6]	N = 1 patient was with PD, aged 63 years.	Intravenous midazolam sedation to reduce movements before assessing condition of the teeth and mouth.	None.	1. Midazolam reduced her involuntary movements after 2 mg of intravenous sedation. 2. A total of 4 mg of midazolam was needed for sedation during treatment. 3. Supplementary oxygen was needed (2l), due to saturation lower than 90%. 4. Sedation with midazolam was not enough, and general anesthesia was needed in order to complete the treatment.
DeMaagd, et al. [8]	Patients, affected with PD, have both symptomatic motor and non-motor features.	Assessing patients’ quality of life.	None.	1. Treatment of symptomatic motor and non-motor features of PD can improve patients’ quality of life
Liu, et al. [10]	N = 1, edentulous patient with PD, 6 years after deep brain stimulation (DBS) procedure.	All-on-4 implantation for rehabilitation of edentulous mandible, with a fixed detachable dental prosthesis.	None.	1. Implants integrated 4 months after the surgery. 2. 1 year after the procedure, soft tissues showed no signs of inflammation. 3. Patient stated that his quality of life has increased considerably.
DeMaagd, et al. [11]	Population of younger patients with PD (45-55 years-old).	Levodopa therapy.	None.	1. Dyskinesia and dystonia are associated with levodopa treatment. The longer the patient uses this drug, the higher the chance of dyskinesia.
Faggion, et al. [12]	Ensuring good hygiene and reducing inflammatory complications for patients, with neurodegenerative diseases, such as PD.	Restoring chewing function with prosthesis on dental implants, and using.	None.	1. It is very important, that the caregivers of the elderly patients also take part in taking care of the prosthesis. 2. Periimplantitis is a very serious disease, which is why, especially for patients, with PD, the number of implants used, should be kept to a minimum.
Sato, et al. [13]	What the optimal dental prosthetic designs to ensure good quality of life for the patients.	Restoring patients’ masticatory function with prosthetic systems that are easy to clean, easy to remove from the mouth, and does not require vigorous cleaning routines.	None.	1. Making designs, of prosthesis, that is easier to clean, over aesthetically good-looking ones. 2. Choosing removable prosthesis, instead of non-removable ones, because they are easier to clean. 3. Improve care givers skills of taking care of the elderly patient’s prosthesis hygiene.
Ribeiro, et al. [14]	N = 17; elders with PD (mean age 69.41 ± 4.65 years; 8 women and 9 men).	Prostheses were rinsed in running water for 5 s to remove food debris. Then, 1% neutral red was applied to eight regions of complete dentures. Biofilm presence on the artificial teeth and acrylic resin in each region of maxillary and mandibular prostheses was scored according to the area covered: 0 = no biofilm, 1 = light biofilm (1% to 25% of area), 2 = moderate biofilm (26% to 50%), 3 = heavy biofilm (51% to 75%), and 4 = very heavy biofilm (76% to 100%). After 7, 14, and 30 days, the presence of biofilm on the artificial teeth and acrylic resin of prostheses were re-evaluated and positive reinforcement was given to participants.	20 elders without PD (mean age 72.00 ± 5.69; 10 women and 10 men).	1. More biofilm was present on the maxillary prostheses of participants with PD than on those of controls at baseline and at 7 and 14 days. 2. Only at 7 days more biofilm was observed on the mandibular prostheses of participants with PD. 3. No difference was observed between groups for maxillary or mandibular prostheses at 30 days. 4. The presence of biofilm on maxillary and mandibular prostheses was reduced over time in both groups (p < 0.05). 5. For the maxillary prostheses, both groups showed hygiene improvement at 7 days, which was maintained throughout the 30-day study period. The mandibular prostheses in the control group showed similar results. 6. The mandibular prostheses of participants with PD showed significant improvement in hygiene only at 14 and 30 days.
Fukuoka, et al. [15]	N = 24; PD patients (12 men, 12 women; mean age ± SD: 70.4 ± 7.9 years; age range 54-89 years).	Tongue pressure when swallowing 5 mL of barium on video fluorography was measured using a sensor sheet with five sensors. The maximal magnitude (kPa), duration(s), time to peak pressure(s), and pressure gradient (kPa/s) of tongue pressure were analyzed.	Dysphagic PD group (n = 9) and non-dysphagic PD group (n = 15).	1. There was no significant difference in maximal tongue pressure between both groups. 2. The dysphagic PD group had prolonged duration of tongue pressure and time to peak pressure and a reduced pressure gradient compared with the non-dysphagic PD group.
Rodrigues Ribeiro, et al. [17]	N = 11. Partially (n = 7) or totally (n = 4) edentulous patients had received rehabilitation with new removable dental prostheses.	Masticatory function was evaluated by mandibular movements, maximum bite force (MBF), and masticatory performance (MP). Mandibular movements reflecting jaw range of motion (ROM) and jaw movements while chewing silicone test material (Optocal), were evaluated using a kinesiograph. MBF was assessed by strain sensors, and MP was determined using the median Optocal particle size (X50) after 40 masticatory cycles.	Evaluations were carried out 30 min before levodopa intake (off-period) and within a 3-day interval 1 hour after levodopa intake (on-period).	During the levodopa off-period, elders showed decreased ROM during protrusion and lateral movements, while no difference was found in maximum opening and mandibular movements during chewing. MBF was lower and X50 was higher during the off-period, indicating worse mastication.
Fereshtehnejad, et al. [18]	Patients with dementia and PD have less dental care visits, than people, who are not affected by these diseases.	The rate of dental visits changes, after the patients were diagnosed with PD.	None.	1. The rate of dental visits per year decreases to 0.8 3 years after the diagnosis of dementia. 2. Caregivers of elderly, affected with dementia and PD should be informed, about the assistance that is required.
Suttrup, et al. [19]	Patients who suffer from PD frequently develop dysphagia.	Impaired swallowing.	None.	1. Swallowing difficulties complicate medication intake, lead to malnutrition and aspiration pneumonia, therefore - reduce patients’ quality of life.
Ribeiro, et al. [20]	N = 17 (mean age 69.59 ± 5.09 years) patients with PD.	Objective assessment: Remaining teeth, DMFT, VPI, salivary flow rate, removable prosthesis conditions. Subjective assessment: Self-perception of oral health using GOHAI index.	N = 20 (mean age 72.00 ± 5.69 years) healthy volunteers.	1. There were no group differences in the number of remaining teeth, DMFT, VPI or salivary flow rate (p > 0.05). 2. GOHAI scores were low for the PD group and moderate for controls (p = 0.04). 3. Elders with PD have similar oral health to controls. 4. Although all elders had few remaining teeth, high DMFT and high VPI, PD elders had more negative self-perceptions of their oral health than did the controls.

DBS: Deep Brain Stimulation; DMFT: Decayed, Missing and Filled Teeth; GOHAI: General Oral Health Assessment Index; MBF: Maximum Bite Force; ME: Masticatory Efficiency; MP: Masticatory Performance; OHIP: Oral Health Impact Profile; OHRQoL: Oral Health Related Quality of Life; PD: Parkinson’s Disease; ROM: Range of Motion; VPI: Visible Plaque Index.