Gingival Recession

A convenience sample of 108 dogs presented for dental care under general anesthesia including complete oral examination and radiographs was recruited from 3 veterinary clinics that consented to participate in the study. These included one referral specialty dental practice (n = 57), one general small animal practice with a focus on veterinary dentistry (n = 29), and the community practice of a veterinary teaching hospital (n = 22). Five veterinarians performed the anesthetic procedures and radiographic assessments.
Dogs likely to show aggression were excluded from enrollment in the study. Prior to sedation, an investigator with previous experience in general veterinary practice performed a VA of each dog’s mouth. The lips and cheeks were retracted to allow the labial and buccal surfaces of the teeth and gingival margins to be examined with a focus on the gingival margins. The mouth was opened slightly to allow examination of the mandibular teeth and gingiva. A full mouth grade of PD between 0 and IV based on the tooth with the greatest level of pathologic change was recorded for each dog. The scoring system was derived from that of the AVDC [19 ]. As illustrated in Table 1, the scale utilized by the investigator(s) did not include the radiographic definitions for each stage of PD. For a subset of the dogs, a second investigator independently evaluated the dog’s teeth at the same visit and recorded the grade of PD in order to determine IRR. After the dental procedure was performed under general anesthesia, the attending veterinarian’s grade for PD was recorded based upon the tooth/teeth with the greatest level of pathology as detected by examination (including periodontal probing for measurement of the degree of gingival recession and attachment loss) and radiography as illustrated in Table 2. Information was also collected on the sex, neuter status, breed, and age of each dog (S1 Appendix).
As listed in the S1 Appendix, a total of 108 dogs were initially enrolled in the study. Informed consent was obtained from the caretaker of each dog enrolled in the study. All experimental procedures were approved by the Clinical Review Panel of the Purdue University College of Veterinary Medicine and the Purdue University Animal Care and Use Committee.
Of the 108 dogs initially enrolled in the study, 11 (10.18%) did not undergo the planned anesthetic procedure, 2 (1.85%) had a diagnosis that was not PD (1 stomatitis, 1 neoplasia), and 6 (5.56%) did not have dental radiography performed. This resulted in a sample of 89 dogs for analysis of agreement with RS (Table 3). The sample included 66 purebred dogs representing 37 breeds along with 21 mixed breed dogs and 2 dogs without breed identified. Mean age was 7.85 years and ranged from 1 to 14 years. Forty-seven dogs were male (41 neutered, 6 intact), and 42 were female (39 spayed, 3 intact).
Fifty-nine dogs (including 7 dogs that did not complete the anesthetic dental procedure, 1 dog with a diagnosis of neoplasia, and 3 dogs that did not have radiographs taken and were thus not included in the RS portion of the study) were evaluated by both of the raters. The sample population consisted of 41 purebred dogs representing 31 different breeds along with 11 mixed breed dogs. Mean age was 7.56 years ranging from 1 to 14 years. Twenty-seven dogs were male (21 neutered, 6 intact) and 32 dogs were female (30 spayed, 2 intact).

A full-mouth periodontal examination was performed on NHANES participants aged ≥30 years between 2009 and 2014. All dental examiners were trained and calibrated by the reference examiner for the survey [70 (link)]. Gingival recession and periodontal pocket depths were measured using periodontal probes at six sites on the teeth, and clinical attachment loss was calculated [70 (link)]. NHANES researchers referred to the consensus recommendations of the CDC for epidemiological studies and the American Academy of Periodontology Prevention for the diagnosis of periodontitis in conducting this research [71 (link),72 (link)].
In the present study, we categorized those with moderate and severe periodontitis into the periodontitis category; those with mild or no periodontitis were grouped into a referent category, to mitigate the risk of bias due to a potentially excessive prevalence of mild periodontitis in the population [73 (link)]. Severe/moderate periodontitis was defined as follows:

≥2 Interproximal sites with a clinical attachment loss (CAL) of ≥4 mm;

≥2 Interproximal sites with a periodontal probing depth of ≥5 mm.

Participants who met one or more of the above two criteria were classified as patients with severe/moderate periodontitis. Referring to previous studies, we excluded edentulous patients and those without complete periodontal examinations [16 (link),74 (link),75 (link)].

Ninety-eight oral photos, including 588 targeted gingivae, were captured from 25 patients admitted at three orthodontic dental clinics in Cheongju city, South Korea, between September 2018 and November 2022. A power analysis was performed using the G*Power software, version 3.1.9.2 (Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany), using mean differences, with mean differences of 0.7% for gingivitis from a related study. An error probability of 0.05 and actual power of 0.95 were used. The number of subjects calculated through the G*Power software was 23. The number of subjects initially included in the study was 30, but in the process of evaluating the quality of the obtained photographs the final number of subjects was selected as 25 participants.
A dental hygienist captured all the photos. The patients were aged between 20 and 39 years. Gingivitis was considered the primary disease in this study. The inclusion criteria were those who had completed orthodontic treatment in their 20s and 30s, had undergone orthodontic treatment for at least six months, had received orthodontic treatment with fixed orthodontic devices, and had been diagnosed with gingivitis by a dentist during orthodontic treatment.
Patients were excluded from the study if they were aged 40 years or older, had systemic disease (such as diabetes and hypertension), had dental caries on the buccal smooth tooth surface, had undergone tooth extraction during orthodontic treatment, had noticeable discoloration of their teeth or had severe melanin pigmentation on the gingiva, or had gingiva that was dark red even though there was no inflammation. In addition, patients with abnormal anatomical structures due to periodontal disease were excluded. The details of exclusion criteria were as follows: subjects with a systemic disease within the past 6 months who are receiving continuous treatment, subjects with other diseases that cause inflammatory transformation of the gingiva, including oral cancer, or subjects taking antibiotics due to disease. Among patients aged ≥ 40 years, some patients with advanced periodontitis were included. Advanced periodontitis can cause alveolar bone loss and gingival recession. The size of the gingiva can be different depending on the participants’ oral condition due to the deformation of the gingiva; therefore, the size of the gingiva was not considered. None of the patients in this study had dental caries on smooth surfaces.
The IOPs used in the research analysis were received by one data organizer who attached a number to each photograph to prevent exposure to personal information and ensure the patients’ anonymity. Then the IOPs were prepared for analysis. The requirement for informed consent was waived because this was a retrospective study and all data were anonymized. We received an exemption for institutional review board review from the Bioethics Review Committee of Cheongju University (1041107-202212-HR-053-01).

After preliminary screening of personal medical history and oral examination at baseline, the participants were randomly assigned to one of the intervention groups: the toothbrush + oral irrigator group (test group) received an OI (WaterPik^® ION Professional Cordless Water Flosser, marketed as GT17 on this region, WaterPik, Inc., Fort Collins, CO, USA) with a uniform standard manual toothbrush (Crest^® Multicolored Crystal Soft Bristles, Procter and Gamble Co., Cincinnati, OH, USA) and a toothpaste (Crest^® Anti-Cavity and Enamel Repair Toothpaste, Procter and Gamble Co., Cincinnati, OH, USA); the toothbrush group (control group) received an identical toothbrush and toothpaste. The OIs allowed for 10 adjustable water pressure settings ranging from 10 to 100 psi, which corresponded to 10 different switches. At baseline, the participants in the test group were instructed to use the OIs in the clinic for the first time by an experienced dental assistant. Furthermore, they were instructed to use the standard jet tip to flush the gingival margin and interdental space twice a day for approximately 90 s before toothbrushing. According to the manufacturer’s recommendations, the participants were advised to adopt the most comfortable water pressure level with a minimum of four. In addition, all participants were instructed to perform manual toothbrushing twice a day with the modified Bass technique. Participants were distributed electronic diaries to record the frequency of toothbrushing and oral irrigation and any adverse reactions or discomfort symptoms. Compliance was evaluated based on the diaries, and it was defined as toothbrushing or oral irrigation ≥ 2 × daily in >80% of study days. Instruction leaflets with toothbrushing methods and oral irrigation instructions were distributed to participants, and they were advised not to use other oral hygiene adjuncts, such as dental floss, interdental brush, and gum.
Before every clinical examination, all participants were instructed to refrain from oral hygiene for 12 h and fast for solids and liquids for 2 h. A single trained examiner evaluated all gingival inflammation-related indices. The MGI [27 ] were examined at four sites (mesial buccal, buccal, distal buccal, and lingual) per tooth. The Bleeding Index (BI) [28 (link)] and percentage of sites with bleeding on probing (BOP%) were examined at six sites (mesial buccal, buccal, distal buccal, mesial lingual, lingual, and distal lingual) per tooth using community periodontal index (CPI) probes. Another trained examiner evaluated the Turesky-Modified Quigley-Hein Plaque Index (T-QH) [29 (link)] after applying the dental plaque disclosing agent. Furthermore, a series of safety observation indicators were evaluated. Gingival recession is defined as apical migration of the gingival margin, and clinically visible sites of gingival recession were examined and recorded. The VAS was adopted to assess the pain and dentin hypersensitivity symptoms during the trial [30 (link)]. The left end of the line segment is marked for no pain or sensitivity symptoms, while the right end represents the most severe pain or sensitivity symptoms. The participants were instructed to mark the line segment according to their existing symptoms during the last month. In addition, vital signs of allergic reactions or lesions in the soft tissue of the oral cavity, including the gingiva, buccal mucosa, lips, palate, vestibular sulcus, tongue, and floor of the mouth, were recorded.
Participants returned to the clinical research center for dental examination at 4 weeks ± 3 days, 8 weeks ± 3 days, and 12 weeks ± 3 days after baseline examinations. The T-QH and gingival inflammation-related indices, including MGI, BI, and BOP%, were reevaluated. Furthermore, the safety indicators were also recorded. The modified Bass technique and the method of OIs use were reinforced at each visit by the same dental assistant. The primary outcomes were gingivitis-related indices after 12 weeks of using OIs. The secondary outcomes were plaque-related indices and gingivitis-related indices at 4 weeks and the safety indicators.

Clinical parameters were assessed by a single experienced and calibrated examiner (MS). Calibration was carried out in five non-study stage III or IV periodontitis patients recording full-mouth PPD and CAL twice with an interval of 24 h and after achieving ≥90% of the recordings with an intra-examiner agreement within 1.0 mm in ≥90%.
The primary outcome measurement was the clinical attachment level gains (CAL-gain) measured from the cemento–enamel junction (CEJ) to the base of the pocket, or from the most apical extension of the restoration/crown. These changes were registered before surgery and 12 months postoperatively at six sites in each affected tooth with a periodontal probe rounded off to the nearest millimeter, being a positive change indicative of CAL-gain (UNC probe 15 mm, Hu-Friedy, Chicago, IL, USA). The site with the greatest presurgical CAL value was used for the statistical analysis.
As secondary clinical outcomes, we evaluated the changes in probing pocket depth (PPD-R) and the changes in gingival recession (GR). Like with the CAL-gains, the site with the greatest presurgical CAL value was used for the statistical analysis.
Full mouth plaque scores (FMPS) were the percentage of total surfaces with the presence of plaque [17 (link)] and full mouth bleeding scores (FMBS), assessed dichotomously, expressed as the percentage of pockets that bled after gentle probing [18 (link)].
Intra-surgical measurements included:

Defect depth as the distance between the bottom of the defect and the most coronal point of the bony walls surrounding the defect;

Defect width as the distance from the most coronal point of the bony walls surrounding the defect to the root surface;

Defects were classified as one-wall, two-wall, and three-wall defects depending on the number of remaining walls.