Effects of Professional Oral Health Care Programs for Elderly Residents of Nursing Facilities

Sample population

The target population was elderly persons aged ≥ 65 years residing in nursing homes in the Gyeonggi and Chungcheong Provinces in the Republic of Korea. Nursing homes were selected through convenience sampling, and informed consent was obtained. Each participant was assigned to either a one-week interval group, two-week interval group, or control group; participants were either bed-ridden patients with complete dependence in activities of daily living (ADL) or demonstrated partial dependence in ADL. Inclusion criteria were individuals who had not received any dental care within the past 6 months. Individuals who refused to open their mouth due to severe cognitive impairment, those with Sjögren’s syndrome, or those who were on salivation stimulation medication were excluded from the study.

A power analysis was performed to determine the minimum sample size required for the t-test and was calculated using G*Power 3.1 for Windows. For a significance level of 0.05, effect size of 0.5, and power of 0.85, at least 38 subjects per group were required, however, considering drop-out, 135 participants (45 per group) was set as the sample size. Shinhan University Institutional Review Board approved the study. Additionally, informed consent from all participants was obtained following the explanation of the study objective and method of participation. In cases of elderly patients with communication difficulties, consent from guardians was received.

To test for homogeneity of the group participants, data on general characteristics, long-term care insurance (LTCI) level, length of stay (LOS), cognitive function, ADL performance, and general health- and oral health-related characteristics were collected via a questionnaire. Initial information regarding gender, age, education level, and participant-partner living arrangement was received prior to starting the questionnaire. The Korean version of Mini-Mental State Examination (MMSE-K)¹⁷ was used to measure cognitive function. ADL performance was assessed using the modified Barthel index, which had been revised to reflect Korean culture and standardized by Jeong et al.¹⁸ Data were collected on the following categories: number of chronic illnesses, number of current medications, recent bouts of pneumonia, daily oral care, refusal of oral care, and xerostomia. General characteristics and cognitive function were asked directly to residents and answers were recorded accordingly. Activities of daily living performance and general health- and oral health-related characteristics were assessed by the nursing staff, social worker, or caregiver.

Intervention

The professional oral health care program was implemented for 12 weeks; at one-week intervals in the one-week interval group, and at two-week intervals in the two-week interval group. In the control group, no professional oral health care program was implemented. The intervention was designed based on the research method used previously by Lee et al.,¹⁵ and was further modified and supplemented through expert consultation with a dentist, two dental hygiene professors, and two clinical dental hygienists. Professional oral care was performed by four dental hygienists and lasted about six minutes per participant. To avoid any experimenter bias, the study participants were randomly assigned to the same dental hygienist each time. Dental hygienists were blinded to group selection.

The professional oral health care intervention was carried out according to the following procedures. The lip area was first cleaned with gauze soaked in a disinfectant mixture of saline and mouth rinse (Listerine, McNeil Consumer Healthcare; Fort Washington, PA, USA). Vaseline Petroleum jelly was then applied to the lips. For participants with dentures, each denture was removed and cleaned of debris via a suction device. The teeth and tongue were cleaned using a combination of rolling brushing, Watanabe brushing, and Bass brushing methods. Interdental brushes were used to clean the interproximal areas in the posterior region. The participant was then asked to rinse with water. If the participant had difficulty with rinsing, a suction device was used to remove the water. After removing debris in the oral cavity, the tongue was wiped using a sponge brush soaked in chlorhexidine and squeezed to remove excess. A moisturizer was then applied. The buccal mucosa was massaged using either the handle of a toothbrush or a finger, the upper/lower lips were stretched outwards for five seconds for each of three cycles, and the buccal and lingual gingivae were massaged using the thumb and index finger. Areas of the parotid, submandibular, and sublingual glands were massaged ten times each. Each participant was provided with an interdental brush and a sponge brush, which were replaced once every two months and at each visit, respectively. Patients wearing dentures were provided with denture cleansers.

Outcome measures

The oral health status pre- and post-intervention was examined to evaluate the effects of the professional oral healthcare program. The O’Leary index,¹⁹ Winkel Tongue Coating Index,²⁰ Löe & Silness gingival index,²¹ and salivary flow rate (SFR),²² were measured. Additionally, an oral examination was performed by a single dentist and post-intervention oral health status was assessed in all groups, three days after program termination.

The O’Leary index¹⁹ is a quantitative measurement of individual oral status. Disclosing agent was applied to all teeth. Each tooth was first divided into four surfaces (mesial, distal, buccal, lingual) and the coloring on each surface was recorded as a score of 0 for “No plaque” or 1 for “With plaque,” indicating poorer hygiene control. The occlusal and incisal surfaces and any missing teeth were excluded from measurement.

Tongue coating was evaluated using the Winkel Tongue Coating Index (WTCI).²⁰ With the patient’s mouth wide open, the tongue was divided into six sections, two vertical sections from tip to base and three horizontal sections. Tongue coating for each section was rated as 0 for “No coating,” 1 for “Light coating,” or 2 for “Heavy coating.” The sum of these scores (range: 0-12) indicated the total amount of coating.

The Löe & Silness gingival index²¹ is widely used for measuring the level of periodontal disease by examining four sections (mesial, distal, buccal, lingual) of the gingival margin. For each section, the level of inflammation was evaluated as 0 for “No inflammation,” 1 for “Mild inflammation with slight changes in color and edema, but no bleeding on probing,” 2 for “Moderate inflammation with redness, edema, and bleeding on probing,” and 3 for “Severe inflammation with redness, hyperplasia, and spontaneous bleeding.” The total sum of the scores was then divided by the total number of gingival margins examined, with 0 indicating healthy gingiva.

Salivary flow rate was measured using the swab method.²² Without having brushed their teeth for two hours following breakfast, participants were asked to swallow to void the mouth of saliva prior to measurement. Dental cotton rolls were placed in the mouth (1.3 × 3.2 cm, Richmond Dental Company; Charlotte, NC, USA): one under the ventral surface (sublingual salivary gland) and one each in the left and right maxillary buccal regions (submandibular salivary glands). After five minutes without any movement, the cotton rolls were removed and their weight was measured using a CB Series (CB-200) digital scale with a resolution of 0.01 g (A&D Co., Ltd., Jinchoen, Korea).

Data analysis

Data was analyzed using SPSS Statistics software (version 22.0, IBM Corporation, Armonk, NY, USA) and the significance level was set to 0.05. A chi-square test was conducted for categorical variables, For continuous variables, one-way analysis of variance (ANOVA) with Scheffe’s post-hoc test was performed. Analysis of covariance (ANCOVA) was conducted to compare post-intervention-measured values between groups. However, SFR was not identified as a significant interaction term for ANCOVA. Therefore, the homogeneity of pre-intervention measurement values was first verified. Then, inter-group comparison of post-intervention measurements was then performed using one-way ANOVA. To identify pre-to-post changes, a paired t-test was performed.