Evaluation of dental caries, tooth crack, and age-related changes in tooth structure using optical coherence tomography

Optical coherence tomography (OCT) is an imaging technique that can visualize the internal biological structure without X-ray exposure. Swept-source OCT (SS-OCT) is one of the latest version of OCT, wherein the light source is a tunable laser that sweeps near-infrared wavelength light to achieve real-time imaging. The imaging depth of OCT is highly influenced by the translucency of the medium. The medium that does not transmit light and the deeper structure beyond the range of light penetration depth are not relevant for OCT imaging. In OCT, sound enamel is almost transparent at the OCT wavelength range, and enamel and dentin can be distinguished from each other as the dentin-enamel junction (DEJ) appears as a dark border. Demineralized enamel and dentin are imaged as bright zones because of the formation of numerous micro-porosities where the backscatter of OCT signal is increased. In cavitated caries at interproximal or occlusal hidden zone, the upper margin of the cavity reflects the signal showing a distinct bright border in the SS-OCT image. SS-OCT is capable of determining crack penetration depth even when the cracks extended beyond the DEJ. SS-OCT has a high degree of sensitivity and specificity for the detection of dental caries and tooth cracks. SS-OCT is also capable of detecting non-carious cervical lesions and occlusal tooth wear in cross-sectional views to estimate the amount of tooth structure loss

Diagnosis of Occlusal Tooth Wear Using 3D Imaging of Optical Coherence Tomography Ex Vivo

The aim of this study was to assess the utility of 3D imaging of optical coherence tomography (OCT) for the diagnosis of occlusal tooth wear ex vivo. Sixty-three extracted human molars with or without visible tooth wear were collected to take digital intraoral radiography and 3D OCT images. The degree of tooth wear was evaluated by 12 examiners and scored using 4-rank scale: 1-slight enamel wear; 2-distinct enamel wear; 3-tooth wear with slight dentin exposure; 4-tooth wear with distinct involvement of dentin. The degree of tooth wear was validated by the histological view of confocal laser scanning microscopy (CLSM). The sensitivity, specificity, and area under the curve (AUC) of receiver operating characteristic analysis were calculated. Diagnostic accuracy was compared with the agreement with CLSM observation using weighted kappa. The results were statistically analyzed at a significance level of alpha = 0.05. Three-dimensional OCT showed significantly higher sensitivity (p 0.05). Three-dimensional OCT could visualize and estimate the degree of tooth wear and detect the dentin exposure at the tooth wear surface accurately and reproducibly. Consequently, a new guideline for tooth wear assessment can be proposed using OCT

The Change of Oral Bacterial Count after Professional Oral Hygiene Care with a Newly Developed Gel and Suctioning

目的：非経口摂取高齢入院患者を対象に「水を使わない口腔ケアシステム」を実施し，口腔細菌数の変化を検証することを目的とした。 方法：非経口摂取高齢入院患者100名を，「水を使わない口腔ケアシステム」（以下，新法）と従来の口腔衛生管理（以下，従来法）の2群に無作為に分け，1日1回連続5日間，歯科衛生士が口腔衛生管理を実施した。1日目の管理直前（以下，ベースライン），管理直後，1時間後と5日目の管理1時間後の計4回，口腔細菌数を測定した。測定値を対数変換して，二元配置分散分析を行った。有意水準は5％とした。 さらにベースラインで細菌数レベル4以上を口腔不潔者とし，5日目に細菌数レベル3以下になった者を「改善あり」，4以上の者を「改善なし」として，χ2検定を行った。 なお本研究は，特定医療法人北九州病院倫理委員会の承認を得て実施した（第15-3号）。 結果：ベースラインと管理直後においては，新法群と従来法群の口腔細菌数に有意差はなく，管理1時間後と5日目においては新法群の細菌数は従来法群よりも有意に低値であった。新法群は，ベースラインと比べて管理直後，1時間後および5日目の細菌数は有意に低下し，管理直後よりも5日目は有意に低下した。従来法群は，ベースラインと比べて管理直後および管理1時間後の細菌数は有意に低下した。また，口腔不潔者のうち，新法群では29名に改善がみられ，従来法群の7名よりも有意に多かった。 結論：本研究における口腔細菌数の変化の結果から，「水を使わない口腔ケアシステム」は従来の方法よりも効果的である可能性が示された。Aim：This study aimed to clarify the change of oral hygiene status after performing a new method of professional oral hygiene care using a newly-developed gel and suctioning with a probe in elderly patients without oral intake based on oral bacterial count. Methods：One hundred elderly patients without oral intake were randomly divided into two groups：the new oral hygiene method using a newly-developed gel and sustained-suctioning with a probe was performed in one group, and the conventional method was performed in the other group. One dental hygienist performed the oral hygiene care for all subjects once a day for five consecutive days. The number of oral bacteria was counted using a bacterial counter four times：at the baseline, immediately after, and 1 hour after the oral hygiene care on the first day, and 1 hour after on the fifth day. The data was statistically analyzed using two-way ANOVA. Additionally, the number of subjects with poor hygiene（level 4 and over）was compared among the two groups at the baseline and at the fifth day and statistically analyzed using the chi-squared test. Results：The oral bacteria count in the new method group was significantly less than that in the conventional method group at immediately after, 1 hour after, and the fifth day. In the new method group, the count at the fifth day was significantly less than at the baseline and immediately after the care. In addition, the number of subjects whose oral hygiene status improved was significantly more in the new method group（29 of 49）than in the conventional group（7 of 47）. Conclusions：The change of oral bacterial count found in this RCT suggested that the new professional oral hygiene method could be more effective than the conventional method

Leiomyosarcoma of the vulva: a case report

Sarcomas represent only 1% to 3% of vulvar malignancies. Leiomyosarcoma is a rare malignant tumor of the vulva; it can be mistaken for a benign tumor, which can lead to misdiagnosis and incorrect or delayed treatment. We report the case of a 51-year-old woman with leiomyosarcoma of the vulva. The patient presented to her primary gynecologist with a vulvar mass that she had first noticed 20 years prior. The tumor was suspected to be aggressive angiomyxoma, and biopsy of the mass and treatment with gonadotrophin-releasing hormone agonist (GnRHa) therapy were recommended. The patient declined treatment and opted instead for observation; however, the tumor grew rapidly in the following year and the patient was referred to our hospital. She underwent tumor resection, and pathology revealed leiomyosarcoma. The patient declined adjuvant chemo- and radiotherapy but has had no recurrence for 32 months

Assessment of Demineralization Inhibition Effects of Dentin Desensitizers Using Swept-Source Optical Coherence Tomography

The purpose of this study was to evaluate the mechanism of action and the inhibiting effects of two types of desensitizers against dentin demineralization using pre-demineralized hypersensitivity tooth model in vitro. In this study, we confirmed that a hypersensitivity tooth model from our preliminary experiment could be prepared by immersing dentin discs in an acetic acid-based solution with pH 5.0 for three days. Dentin discs with three days of demineralization were prepared and applied by one of the desensitizers containing calcium fluoro-alumino-silicate glass (Nanoseal, NS) or fluoro-zinc-silicate glass (Caredyne Shield, CS), followed by an additional three days of demineralization. Dentin discs for three days of demineralization (de3) and six days of demineralization (de6) without the desensitizers were also prepared. The dentin discs after the experimental protocol were scanned using swept-source optical coherence tomography (SS-OCT) to image the cross-sectional (2D) view of the samples and evaluate the SS-OCT signal. The signal intensity profiles of SS-OCT from the region of interest of 300, 500, and 700 mu m in depth were obtained to calculate the integrated signal intensity and signal attenuation coefficient. The morphological differences and remaining chemical elements of the dentin discs were also analyzed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. SS-OCT images of CS and NS groups showed no obvious differences between the groups. However, SS-OCT signal profiles for both the CS and NS groups showed smaller attenuation coefficients and larger integrated signal intensities than those of the de6 group. Reactional deposits of the desensitizers even after the additional three days of demineralization were observed on the dentin surface in NS group, whereas remnants containing Zn were detected within the dentinal tubules in CS group. Consequently, both CS and NS groups showed inhibition effects against the additional three days of demineralization in this study. Our findings demonstrate that SS-OCT signal analysis can be used to monitor the dentin demineralization and inhibition effects of desensitizers against dentin demineralization in vitro

3D imaging of proximal caries in posterior teeth using optical coherence tomography

Optical coherence tomography (OCT) can create cross-sectional images of tooth without X-ray exposure. This study aimed to investigate the diagnostic accuracy of 3D imaging of OCT for proximal caries in posterior teeth. Thirty-six human molar teeth with 51 proximal surfaces visibly 6 intact, 16 slightly demineralized, and 29 distinct carious changes were mounted to take digital radiographs and 3D OCT images. The sensitivity, specificity and area under the receiver operating characteristic curve (AUC) for the diagnosis of enamel caries and dentin caries were calculated to quantify the diagnostic ability of 3D OCT in comparison with digital radiography. Diagnostic accuracy was evaluated by the agreement with histology using weighted Kappa. OCT showed significantly higher sensitivity, AUC and Kappa values than radiography. OCT can be a safer option for the diagnosis of proximal caries in posterior teeth that can be applied to the patients without X-ray exposure

A pilot study to assess the morphology and progression of non-carious cervical lesions

Objective: This longitudinal pilot study aimed to morphologically and quantitatively investigate the progress of non-carious cervical lesions (NCCLs) by using swept-source optical coherence tomography (SS-OCT). Methods: The samples examined comprised sets of NCCL epoxy resin replicas obtained from 10 lesions in 6 patients who attended annual dental visits over 4 or 5 years. SS-OCT images of the replicas were analyzed in terms of the maximum depth (Dmax) and corresponding vertical width (VW) ? using an image analyzer to estimate progression of the NCCLs over time. Results: It was found that differences between wedge- and saucer-shaped lesions were morphologically distinguished well by the OCT images. There were significant differences in dimensions among Dmax, VW and horizontal width (HW). HW was the largest and Dmax was the smallest. Although no significant differences in absolute values of annual progression rates were found among Dmax, VW and HW, the percentage increase in Dmax was significantly greater compared to VW and HW. The ratios of Dmax to corresponding VW ranged from 0.49 to 1.01 for the wedge-shaped lesions and from 0.13 to 0.44 for saucer-shaped lesions, respectively. Conclusions: The dimensional analysis demonstrated notable progression with large variations. The wedge-shaped lesions appeared to show greater Dmax values compared to the saucer-shaped lesions. Clinical significance: With respect to the depth, the wedge-shaped lesions may progress at a greater rate compared to the saucer-shaped lesions

Longitudinal MRI follow-up of rheumatoid arthritis in the temporomandibular joint: importance of synovial proliferation as an early-stage sign

This article describes longitudinal magnetic resonance imaging (MRI) observations in a patient with rheumatoid arthritis of the temporomandibular joint. The characteristic findings included marked synovial proliferation, which was observed before the onset of severe bone destruction. MRI is considered to provide valuable information for the early detection of rheumatoid arthritis of the temporomandibular joint

Colonization of the Tongue Surface in Japanese Independent Elders: A Preliminary Study

Oral care is important to decrease oral bacteria, especially in the dependent elders. There have been some reports on oral microflora in the dependent elders. However, investigations involving healthy independent elders are limited. The purpose of this study was to obtain more information on the microflora in Japanese independent elders. One hundred Japanese independent elders aged 65 years or older participated in this study. Eighty-one independent elders (male: 44, female: 37, mean age: 72.7 ± 5.8) participated in this study. Their mean Barthel Index was 99.1 ± 3.1, and mean score of MMSE was 28.0 ± 2.3. The tongue bacterial flora was examinved to identify microorganisms by the culture method. The predominant aerobic organisms were Streptococcus spp. (detection rate: 100%), Neisseria spp. (96%), and Corynebacterium spp. (56%). Candida spp. was also isolated (32%). In this study, the oral microflora of the tongue in Japanese independent elders was clarified. The results of this investigation may contribute to research on oral bacteria in elder persons in the future