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Methionine challenge test: methyl mercaptan (CH3SH) response in periodontitis

Mon, 01 Jun 2026 00:00:00 GMT

Title: Methionine challenge test: methyl mercaptan (CH3SH) response in periodontitis Authors: Choi, Yiseul; Song, Yoolbin; Kim, Sooyeon; Park, Wonse Abstract: Halitosis, frequently associated with volatile sulfur compounds (VSCs) produced by oral microbiota, affects a large proportion of adults. Among VSCs, methyl mercaptan (CH3SH) is a critical biomarker for periodontitis-related halitosis due to its strong correlation with periodontal pocket depth and attachment loss. This study investigated the utility of a methionine challenge protocol to selectively stimulate CH3SH production and enhance the standardization of oral air-based screening for periodontal disease. Thirty adults were enrolled and divided equally into control and periodontitis groups. Mouth air samples were collected from oral cavity air using a straw-based sampling method connected to a portable gas-sensing device, which continuously monitored VSCs, including CH3SH and hydrogen sulfide (H2S), across eight time points. Participants underwent an 8 h fast prior to baseline oral air collection, followed by standardized toothbrushing. After a 60 min rest period, they swilled with a methionine solution, with oral air samples collected immediately after and at 10 min intervals for 40 min. Both groups showed increased CH3SH levels following methionine stimulation, with the periodontitis group exhibiting a significantly greater increase from pre- to post-stimulation (p < 0.001) and higher cumulative exposure (p < 0.001). In contrast, H2S levels remained consistently elevated in the periodontitis group but did not fluctuate significantly over time. Furthermore, correlations between CH3SH and H2S decreased immediately post-stimulation and gradually recovered in the periodontitis group. These findings indicate that the methionine challenge effectively induces CH3SH production linked to periodontal dysbiosis, supporting its potential as a non-invasive screening and indicator tool for the presence of periodontitis, rather than for staging disease severity. The protocol offers a promising approach to improve diagnostic accuracy while minimizing variability related to oral hygiene. (The study is registered with the Clinical Research Information Service under number KCT0010328.).

Long-Term Survival Rates of Dental Implants in Patients With Disabilities: A Retrospective Clinical Study With up to 10 Years Follow-Up

Fri, 01 May 2026 00:00:00 GMT

Title: Long-Term Survival Rates of Dental Implants in Patients With Disabilities: A Retrospective Clinical Study With up to 10 Years Follow-Up Authors: Kim, Yoon-Jung; Doh, Re-Mee; You, Tae Min; Jung, Bock-Young; 도레미 Abstract: Background Dental implant therapy is increasingly offered to patients with physical, cognitive or multiple disabilities; however, their long-term survival and complication patterns remain poorly defined.Objectives To determine the 10-year cumulative survival rate of dental implants and characterize biological and mechanical complications in patients with disabilities treated at a single university oral care centre.Methods We retrospectively reviewed clinical and radiographic records of patients who underwent implant surgery between 2013 and 2023. Implant outcomes were classified based on established clinical and radiographic criteria for survival and failure. Kaplan-Meier analysis estimated cumulative survival, and subgroup analyses compared outcomes by disability type. Prosthetic complications were evaluated only in implants with definitive restorations.Results A total of 137 patients (465 implants) were analysed; 35 patients (117 implants) did not receive definitive prostheses. The mean age of the patients at surgery was 46.3 years. The 10-year cumulative implant survival rate was 98.3%. Subgroup survival rates were 99.1% (mental impairment), 98.1% (physical impairment) and 95.7% (multiple disabilities). Seven implants failed (five early biologic failures before prosthesis delivery; two mechanical failures, including one traumatic fixture fracture and one abutment screw fracture). Biological complications occurred in 11 restored implants, whereas mechanical complications were more frequent, predominantly crown decementation (n = 32), followed by veneer chipping (n = 12), screw loosening (n = 12) and screw fracture (n = 3).Conclusions Within the limitations of this retrospective single-centre cohort, careful surgical planning, simplified prosthetic design and structured caregiver-inclusive maintenance were associated with high long-term implant survival in patients with disabilities.

Voice Recognition for Periodontal Probing Medical Records under Korean-English Bilingual Conditions: A Feasibility Study

Wed, 01 Apr 2026 00:00:00 GMT

Title: Voice Recognition for Periodontal Probing Medical Records under Korean-English Bilingual Conditions: A Feasibility Study Authors: Kim, Young Woo; Kook, Jin Hyeok; Choi, Yiseul; Park, Wonse Abstract: Objectives: This study evaluated the feasibility of voice recognition-based electronic medical record (EMR) documentation for periodontal probing in dentistry, particularly emphasizing Korean-English bilingual speech patterns and real-world clinical conditions. Methods: Experiments were conducted in a dental chair setting during routine clinical hours. Environmental noise levels were measured, and two microphone types (stationary and pin-type) were evaluated. Periodontal probing phrases composed of three-digit numbers and positional terms were used for speech recognition. Consistent with common clinical practice in Korea, numerical values were spoken in Korean, whereas positional terms were spoken in English. Two speech-to-text application programming interfaces, Google Cloud Speech-to-Text and Naver Clova Speech Recognition, were assessed. Recognition accuracy was evaluated for both numerical components and complete bilingual phrases. Results: The mean environmental noise level was 60.65 dB and was minimally influenced by activity at adjacent dental chairs. The stationary microphone failed to capture speech effectively, whereas the pin-type microphone demonstrated stable recognition performance. For three-digit number recognition, accuracy was 88.3% with Google and 96.8% with Naver. For full-phrase recognition, complete matching was achieved in 36.7% of cases for Google and 52.5% for Naver. Partial recognition occurred more frequently for numerical components than for English positional terms. Conclusions: Voice recognition-based EMR documentation for periodontal probing demonstrated preliminary feasibility in a dental clinical environment; however, performance was influenced by Korean-English bilingual speech patterns. These findings suggest that bilingual speech characteristics should be considered when implementing voice recognition systems in dental EMR workflows. Further optimization is required before routine clinical application.

Shotgun metagenomic analysis of the tongue-coating microbiome reveals oral microbes and their functions in older adults with dementia

Sun, 01 Mar 2026 00:00:00 GMT

Title: Shotgun metagenomic analysis of the tongue-coating microbiome reveals oral microbes and their functions in older adults with dementia Authors: Cha, Jun Hyung; Jeong, Sol-Ah; Ye, Byoung-Seok; Lee, Insuk; Jung, Bock-Young Abstract: IntroductionDementia poses a growing burden in the aging population, prompting the search for noninvasive biomarkers for early detection.Materials and methodsWe performed shotgun metagenomic sequencing of tongue-coating samples from older adults with dementia (n = 30) and cognitively healthy controls (n = 28) to identify oral microbiome signatures.ResultsThe analysis revealed distinct microbial compositions associated with dementia, including an enrichment of Veillonella parvula in dementia patients, whereas Lautropia dentalis was more abundant in healthy controls. We also identified functional alterations in the microbiome in the dementia group, including increased abundance of the histidine degradation and biotin biosynthesis pathways, whereas ubiquinol biosynthesis was more abundant in the healthy control group. The abundance of several microbial taxa and metabolic pathways were correlated with scores on the Korean Mini-Mental State Examination 2nd edition (K-MMSE), a clinical assessment of dementia severity. Prevotella pleuritidis, Actinomyces sp., Leptotrichia buccalis, and Leptotrichia sp. were positively correlated, whereas Oribacterium parvum was negatively associated with K-MMSE scores. Among the metabolic pathways, glutamine/glutamate biosynthesis was positively correlated with cognitive performance.ConclusionsThese results suggest that specific oral taxa and their metabolic functions are associated with cognitive status and may reflect underlying neurodegenerative processes.