Effect of soft denture liners on complete denture treatments: A systematic review

PURPOSE

This systematic review examined the effectiveness of soft denture relining (SDR) materials.

STUDY SELECTION

A comprehensive search of MEDLINE, Cochrane Library, and ICHUSHI was conducted up to July 26, 2020. Target outcomes were patient satisfaction, oral health-related quality of life (OHRQOL), masticatory ability (MA), denture functional duration, residual ridge resorption (RRR), and microbial contamination. An organization specializing in literature searches performed the reference searches, and two reviewers independently selected the literature sources, extracted the data, and assessed the risk of bias. The reviewers resolved any disagreements concerning the assortment of literature sources through discussion. SDR included acrylic- and silicone-based materials, which were evaluated separately.

RESULTS

Reviewers selected 7, 5, 11, 1, 4, and 6 studies to assess patient satisfaction, OHRQOL, MA, functional duration, RRR, and microbial contamination, respectively. The results confirmed that SDR improved patient satisfaction, OHRQOL, MA, and RRR. However, the functional duration of SDR material is shorter than that of hard denture relining (HDR) or acrylic resin material. Furthermore, SDR material is more susceptible to microbial contamination in the long term. The risk of bias for the included studies tended to be high because of specific issues (difficulty in blinding SDR versus HDR).

CONCLUSIONS

For patients who wear complete dentures, SDR often provides beneficial outcomes such as pain reduction and recovery from MA. However, caution should be exercised regarding their use owing to insufficient functional duration and the possibility of microbial contamination during long-term use.

Job shadowing for early undergraduate dental students: Evaluation and validation of educational effectiveness using structural equation modelling

INTRODUCTION

This study aimed to evaluate and validate the educational effectiveness of a job shadowing class as a dental teaching programme for preclinical dental students through a questionnaire that assessed related student perceptions.

MATERIALS AND METHODS

A total of 124 preclinical (second year) dental students at Tokushima University participated in job shadowing placements from 2017 to 2019. Each student observed dental practice or surgery for 1 day in the university hospital. After shadowing, the students were requested to fill out a nine-item questionnaire based on a five-point scale. The first analysis was performed to calculate the correlation for each item. Furthermore, regression analysis for the categorical data was performed to show the relationship between eight questions (Items 1-8) and one question (Item 9: comprehensive evaluation). Next, factor analysis was performed to determine students' perceptions regarding the shadowing class.

RESULTS

Ninety-eight students (response rate: 79%) completed the questionnaire. There was a strong relationship amongst Items 1, 8 and 9 ("interested in dentistry as a job," "learning motivation" and "comprehensive evaluation" respectively) based on the results of the correlation and regression analysis. The factor analysis led to three student perceptions as latent factors, namely, "Interesting," "Self-awareness" and "Future Goal," which had a relatively close inter-factor correlation (0.465-0.772).

CONCLUSION

The finding suggests that job shadowing may increase a students' interest in a dentistry career at an early stage of their education and learning motivation, along with generating self-awareness. This programme may present possible educational effectiveness in dental education.

Mechanism and clinical use of botulinum neurotoxin in head and facial region

PURPOSE

Botulinum neurotoxin (BoNT) is a biological toxin produced by Clostridium botulinum. BoNT is a potent toxin extensively used in therapeutic interventions. This review provides an updated overview of the mechanisms of action and clinical applications of BoNT in head and facial region.

STUDY SELECTION

MEDLINE/PubMed searches were conducted using the terms "botulinum neurotoxin" and "dentistry" along with a combination of other related terms. In addition, studies were manually selected from reference lists of the selected articles.

RESULTS

The Food and Drug Administration in the United States initially approved BoNT to treat strabismus, blepharospasm, and hemifacial spasms. The use of BoNT in dermatology and cosmetics has been widely established and has created a revolution in these fields. Over the years, its applications in various medical specialties have expanded widely. Owing to its safety, efficacy, and long duration of action, it is well-accepted by patients. BoNT/A and BoNT/B are widely used in clinical practice. Several off-label uses of BoNT in the dental fraternity have yielded promising results. We have elaborated on the speculated mechanism of action, dosage, effective sites of injection, and adverse effects of each therapeutic application. The various clinical indications for BoNT include bruxism, myofascial pain, temporomandibular joint dislocation, hemifacial pain, orofacial dystonia, facial paralysis, chronic migraine, and trigeminal neuralgia.

CONCLUSIONS

BoNT is a safe treatment that can be used effectively, provided that the clinician has adequate knowledge regarding the mechanism, injection techniques, and local and systemic side effects and that it is administered cautiously and purposefully.

Targeted Therapy for Orofacial Pain: A Novel Perspective for Precision Medicine

Orofacial pain (OFP) is a dental specialty that includes the diagnosis, management and treatment of disorders of the jaw, mouth, face, head and neck. Evidence-based understanding is critical in effectively treating OFPs as the pathophysiology of these conditions is multifactorial. Since OFP impacts the quality of life of the affected individuals, treating patients successfully is of the utmost significance. Despite the therapeutic choices available, treating OFP is still quite challenging, owing to inter-patient variations. The emerging trends in precision medicine could probably lead us to a paradigm shift in effectively managing the untreatable long-standing pain conditions. Precision medicine is designed based on the patient's genetic profile to meet their needs. Several significant relationships have been discovered based on the genetics and genomics of pain in the past, and some of the notable targets are discussed in this review. The scope of this review is to discuss preclinical and clinical trials that include approaches used in targeted therapy for orofacial pain. Future developments in pain medicine should benefit from current trends in research into novel therapeutic approaches.

Identification of microRNA Signatures in Peripheral Blood of Young Women as Potential Biomarkers for Metal Allergy

MicroRNA (miRNA) is a short (19-24 nucleotide) endogenous non-protein RNA that exists in the body and controls the translation process from genes to proteins. It has become useful as a diagnostic tool and a potential treatment target in cancer research. To explore the function of miRNA in contact dermatitis, female participants with a positive metal allergy diagnosis (n = 3) were enrolled along with additional female participants with no medical history of metal allergy (n = 3). A patch test was performed on each participant. Peripheral blood was collected from all the participants before the patch test and at days 3 and 7 after starting the patch test. After total RNA was obtained from peripheral blood leukocytes and cDNA was generated, microarray analysis was performed to analyze the large-scale circulating miRNA profile. Real-time polymerase chain reaction (RT-PCR) was then used to clarify the overall target miRNA expression. Downregulation of hsa-let-7d-5p, hsa-miR-24-3p, hsa-miR-23b-3p, hsa-miR-26b-5p, and hsa-miR-150-5p was found on day 7. Certain miRNAs were confirmed using RT-PCR. These peripheral blood miRNAs could be diagnostic biomarkers for metal allergies.

Physical Load While Using a Tablet at Different Tilt Angles during Sitting and Standing

Few standards and guidelines to prevent health problems have been associated with tablet use. We estimated the effects of posture and tablet tilt angle on muscle activity and posture in healthy young adults. Seventeen healthy young adults (age: 20.5 ± 3 years) performed a cognitive task using a tablet in two posture (sitting and standing) and tablet tilt angle (0 degrees and 45 deg) conditions. Segment and joint kinematics were evaluated using 16 inertial measurement unit sensors. Neck, trunk, and upper limb electromyography (EMG) activities were monitored using 12 EMG sensors. Perceived discomfort, kinematics, and EMG activities were compared between conditions using the Friedman test. The perceived discomfort in the standing-0 deg condition was significantly higher than in the remaining three conditions. Standing posture and tablet inclination significantly reduced the sagittal segment and joint angles of the spine, compared with sitting and flat tablet conditions. Similarly, standing posture and tablet inclination significantly reduced EMG activities of the dorsal neck, upper, and lower trunk muscles, while increasing EMG activity of shoulder flexors. Standing posture and tablet inclination reduced the sagittal flexion angle, and dorsal neck, upper, and lower trunk muscle activities, while potentially increasing the muscle activity of arm flexors.

Therapy outcome measures in temporomandibular disorder: a scoping review

OBJECTIVES

Therapy outcome measures (TOMs) in temporomandibular disorders (TMDs) have not been systematically evaluated. We systematically explored the main TOM assessment methods for TMD TOMs used in previous studies.

DESIGN

Scoping review.

DATA SOURCES

According to Preferred Reporting Items for Systematic reviews and Meta-Analysis extension for Scoping Review reporting guidelines, we systematically searched five key databases (MEDLINE/PubMed, Web of Science, Embase, Epistemonikos and ClinicalTrials) and thoroughly scanned relevant grey literature using Medical Subject Headings, Emtree and index terms.

ELIGIBILITY CRITERIA

We considered primary research papers published from January 2010 to December 2020 that included patients with TMD aged ≥18 years, diagnosed according to the Diagnostic Criteria for Temporomandibular Disorders.

DATA EXTRACTION AND SYNTHESIS

Four reviewers extracted general information and information on study design and setting, target, interventions, and outcome type.

RESULTS

One hundred and seventy-two of the 3726 screened articles (3704 by search engines and 22 manually) were included. The TOMs analysed included pain (n=161 articles), maximal mouth opening (MMO) (91), jaw function (32), jaw movement (26), joint sound (16), quality of life (QOL) (15), depression/anxiety (14), oral QOL (10) or others (30). Evaluation periods were <4 weeks (111), <8 weeks (62), <12 weeks (59), >12 weeks (75) or 'not mentioned' (12). Pain outcomes (229) included general pain (115), tenderness (45), pain during functioning (44), resting pain (16) and others (8). Pain outcome evaluation methods included Visual Analogue Scale (VAS; 121), Numerical Rating Scale (21) and other methods (21). Pain outcome indicators were binary (10) or continuous (158); only five studies reported the least significant difference in treatment efficacy. MMO evaluation using painless methods (19) and jaw function evaluation using methods assessing mandibular movement range (23) were the most frequent.

CONCLUSIONS

TMD TOMs are diverse; the major outcomes were pain, MMO, jaw function and jaw movement. Most pain outcomes are evaluated by VAS Score changes.

Dual orexin receptor antagonist drug suvorexant can help in amelioration of predictable chronic mild stress-induced hyperalgesia

AIMS

This study aimed to evaluate the involvement of the orexin system in predictable chronic mild stress (PCMS) and the effects of suvorexant, a dual orexin receptor antagonist, on nociceptive behavior in PCMS.

MATERIALS AND METHODS

Male C57BL/6 J mice were separated into various PCMS groups: a control group with sawdust on the floor of the rearing cage (C), a group with mesh wire on the floor (M), and a group with water just below the mesh wire (W). Activation of lateral hypothalamic orexin neurons was assessed using immunofluorescence. In another experiment, half of the mice in each group were administered an intraperitoneal injection of suvorexant (10 mg/kg), and the remaining mice were injected with the same amount of vehicle (normal saline). Thermal hyperalgesia was examined using tail immersion and hot plate tests, while mechanical hyperalgesia was investigated using the tail pinch test after 21 days of PCMS.

KEY FINDINGS

Animals subjected to PCMS showed an increased percentage of activated orexin neurons in the lateral hypothalamic region after 21 days. Mice raised in the PCMS environment showed increased pain sensitivity in several pain tests; however, the symptoms were significantly reduced by suvorexant administration.

SIGNIFICANCE

The findings revealed that PCMS activates hypothalamic orexin neuronal activity, and the use of suvorexant can help attenuate PCMS-induced thermal and mechanical hyperalgesia.

Analgesic Effect of Tranilast in an Animal Model of Neuropathic Pain and Its Role in the Regulation of Tetrahydrobiopterin Synthesis

Trigeminal neuralgia is unilateral, lancinating, episodic pain that can be provoked by routine activities. Anticonvulsants, such as carbamazepine, are the drugs of choice; however, these possess side-effects. Microvascular decompression is the most effective surgical technique with a higher success rate, although occasionally causes adverse effects. The potential treatment for this type of pain remains unmet. Increased tetrahydrobiopterin (BH4) levels have been reported in association with axonal injury. This study aimed to evaluate the effect of tranilast on relieving neuropathic pain in animal models and analyze the changes in BH4 synthesis. Neuropathic pain was induced via infraorbital nerve constriction. Tranilast, carbamazepine, or saline was injected intraperitoneally to assess the rat's post-intervention pain response. In the von Frey's test, the tranilast and carbamazepine groups showed significant changes in the head withdrawal threshold in the ipsilateral whisker pad area. The motor coordination test showed no changes in the tranilast group, whereas the carbamazepine group showed decreased performance, indicating impaired motor coordination. Trigeminal ganglion tissues were used for the PCR array analysis of genes that regulate the BH4 pathway. Downregulation of the sepiapterin reductase (Spr) and aldoketo reductase (Akr) genes after tranilast injection was observed compared to the pain model. These findings suggest that tranilast effectively treats neuropathic pain.

Orofacial Pain: Molecular Mechanisms, Diagnosis, and Treatment 2021

The Special Issue “Orofacial Pain: Molecular Mechanisms, Diagnosis, and Treatment 2021” contains 6 articles published by 41 authors from different countries focusing on nucleus accumbens core GABAergic neurons, receptor-interacting serine/threonine-protein kinase 1, pannexin 1-mediated ATP signaling, ultra-low-frequency transcutaneous electrical nerve stimulation, and triamcinolone acetonide. The content covers several pain models, including neuropathic pain caused by peripheral nerve constriction or malpositioned dental implants, tongue cancer, myogenous temporomandibular dysfunction, and oral ulcerative mucositis. In addition, a review paper on trigeminal neuralgia is included.

Conditioned Medium From the Stem Cells of Human Exfoliated Deciduous Teeth Ameliorates Neuropathic Pain in a Partial Sciatic Nerve Ligation Model

In neuropathic pain (NP), injury or diseases of the somatosensory system often result in highly debilitating chronic pain. Currently, there is no effective drug for the complete and definitive treatment of NP. We investigated the therapeutic potential of conditioned medium (CM) derived from stem cells from human exfoliated deciduous teeth (SHED-CM) against NP using a mouse partial sciatic nerve ligation (PSL) model. Abnormal pain sensation, such as tactile allodynia and hyperalgesia, can be caused by PSL. In the behavioral test, intravenous administration of SHED-CM greatly improved the PSL-induced hypersensitivity. We found that treatment with SHED-CM resulted in the recruitment of M2 macrophages in the injured sciatic nerve and ipsilateral L4/L5 dorsal root ganglion and suppressed microglial activation in the spinal cord. Notably, specific depletion of the anti-inflammatory M2 macrophages by mannosylated-Clodrosome markedly reduced the antinociceptive effect of SHED-CM. Intravenous administration of CM from M2 induced by SHED-CM (M2-CM) ameliorated the PSL-induced hypersensitivity. We found that M2-CM directly suppressed the expression of nociceptive receptors as well as proinflammatory mediators in Schwann cells. Taken together, our data suggest that SHED-CM ameliorates NP through the induction of the analgesic anti-inflammatory M2 macrophages. Thus, SHED-CM may be a novel therapeutic candidate for NP.

Dentin-Pulp Complex Tissue Regeneration via Three-Dimensional Cell Sheet Layering

The dentin-pulp complex is a unique structure in teeth that contains both hard and soft tissues. Generally, deep caries and trauma cause damage to the dentin-pulp complex, and if left untreated, this damage will progress to irreversible pulpitis. The aim of this study was to fabricate a layered cell sheet composed of rat dental pulp (DP) cells and odontogenic differentiation of pulp (OD) cells and to investigate the ability to regenerate the dentin-pulp complex in a scaffold tooth. We fabricated two single cell sheets composed of DP cells (DP cell sheet) or OD cells (OD cell sheet) and a layered cell sheet made by layering both cells. The characteristics of the fabricated cell sheets were analyzed using light microscopy, scanning electron microscope (SEM), hematoxylin-eosin (HE) staining, and immunohistochemistry (IHC). Furthermore, the cell sheets were transplanted into the subrenal capsule of immunocompromised mice for 8 weeks. After this, the regenerative capacity to form dentin-like tissue was evaluated using micro-computed tomography (micro-CT), HE staining, and IHC. The findings of SEM and IHC confirmed that layered cell sheets fabricated by stacking OD cells and DP cells maintained their cytological characteristics. Micro-CT of layered cell sheet transplants revealed a mineralized capping of the access cavity in the crown area, similar to that of natural dentin. In contrast, the OD cell sheet group demonstrated the formation of irregular fragments of mineralized tissue in the pulp cavity, and the DP cell sheet did not develop any hard tissue. Moreover, bone volume/tissue volume (BV/TV) showed a significant increase in hard tissue formation in the layered cell sheet group compared with that in the single cell sheet group (p < 0.05). HE staining also showed a combination of soft and hard tissue formation in the layered cell sheet group. Furthermore, IHC confirmed that the dentin-like tissue generated from the layered cell sheet expressed characteristic markers of dentin but not bone equivalent to that of a natural tooth. In conclusion, this study demonstrates the feasibility of regenerating dentin-pulp complex using a bioengineered tissue designed to simulate the anatomical structure. Impact statement The dentin-pulp complex can be destroyed by deep caries and trauma, which may cause pulpitis and progress to irreversible pulpitis, apical periodontitis, and even tooth loss. Current treatments cannot maintain pulp health, and teeth can become brittle. We developed a three-dimensional (3D) layered cell sheet using dental pulp cells and odontogenic differentiation of pulp cells for dentin-pulp complex regeneration. Our layered cell sheet enables the regeneration of an organized 3D dentin-pulp-like structure comparable with that of natural teeth. This layered cell sheet technology may contribute to dentin-pulp complex regeneration and provide a novel method for complex tissue engineering.

Risk Factors for Tooth Loss in Patients with ≥25 Remaining Teeth Undergoing Mid-Long-Term Maintenance: A Retrospective Study

Tooth loss represents a diffused pathologic condition affecting the worldwide population. Risk factors have been identified in both general features (smoking, diabetes, economic status) and local tooth-related factors (caries, periodontitis). In this retrospective study, we examined the data of 366 patients with a large number of remaining teeth (≥25) undergoing maintenance therapy in order to identify specific risk factors for tooth loss. The number of remaining teeth, number of non-vital teeth, and number of occlusal units were investigated for their correlation with tooth loss. The mean follow-up of patients was 9.2 years (range 5 to 14). Statistically significant risk factors for tooth loss were identified as number of remaining teeth at baseline (p = 0.05), number of occlusal units (p = 0.03), and number of non-vital teeth in posterior regions (p < 0.001). Multiple logistic regression showed that the number of occlusal units and number of non-vital teeth in the posterior regions were significantly associated with a greater risk of tooth loss (odds ratio 1.88 and 3.17, respectively). These results confirm that not only the number of remaining teeth, but also their vital or non-vital status and the distribution between the anterior and posterior regions influence the long-term survival.

Decreased Global Interest in Oral Cancer During the COVID-19 Pandemic

Objective:

Oral cancer is one of the most common malignancies in developing countries, but studies using global data are scarce. The aim of this study is to analyze the search interests for oral cancer using mouth cancer, tongue cancer, gum cancer, and lip cancer as common keywords.

Methods:

Internet searches relating to oral cancer from 2010 to 2020, from 250 countries and dependent areas, were retrieved from Google Trends. Color densities in a heat map were used to show geographic differences. Kruskal-Wallis test with post hoc Dunn’s analysis was used to perform yearly comparisons of searches for mouth cancer, tongue cancer, gum cancer, and lip cancer. Search results within 2020 were also compared to determine differences. Forecasting searches from 2021 to 2022 were done by fitting time series models.

Results:

From 29 of 250 (11.6%) countries, the highest search values were observed for mouth cancer in Sri Lanka, Qatar, Bangladesh, Finland, Netherlands, Spain, and France. Compared to 2020, greater searches were seen in 2018 (Mdn = 91%, P = 0.023) and 2019 (Mdn = 94%, P = 0.012) for mouth cancer, and 2019 (Mdn = 17%, P = 0.035) for lip cancer. The relative search volumes for gum cancer and lip cancer were substantially lower than mouth cancer during the COVID-19 pandemic.

Conclusion:

Higher-income countries tend to be more interested in seeking information about oral cancer. Noteworthy decline in the interest in seeking information online for oral cancer may have crucial implications during the COVID-19 pandemic. Google Trends offer an invaluable and inexpensive means for oral cancer surveillance and health-seeking behavior.

Effects of sitting posture and jaw clenching on neck and trunk muscle activities during typing

Neck pain is one of the most common musculoskeletal complaints. Evidence suggests that increased activities of neck and trunk muscles are one of the mechanisms related to neck pain. Jaw clenching and sitting posture may modulate the muscle activity in neck and trunk muscles during typing. The present study aimed to assess the effects of different postural positions and clenching conditions on neck and trunk muscle activities. Thirteen healthy adults (39.8 ± 5.0 years) performed computer typing tasks in four conditions (two postural positions [upright vs slouched] and two jaw clenching conditions [clenching vs non-clenching]). Integrated surface electromyography (iEMG) was measured in sternocleidomastoid (SCM), upper trapezius (uTP) and middle trapezius (mTP) muscles and compared between conditions. The Friedman and Wilcoxon signed-rank tests with Bonferroni's corrections were used to estimate the condition-specific differences in the iEMG data. The statistical significance level was set at 5%. In both postural positions, iEMG_SCM was significantly greater under the jaw clenching than under the non-clenching condition (χ²  = 21.700, P < .01). Under both jaw clenching conditions, iEMG_uTP was significantly greater in the slouched than in the upright postural position (χ²  = 23.182, P < .01). No significant differences in iEMG_mTP were seen across conditions (χ²  = 5.018, P = .10). Sitting posture and jaw clenching appear to influence activities of different muscles.

Immediate Effect of Masticatory Muscle Activity with Transcutaneous Electrical Nerve Stimulation in Muscle Pain of Temporomandibular Disorders Patients

Transcutaneous electrical nerve stimulation (TENS) is a non-invasive treatment modality for acute and chronic pain. However, little information for muscle activity is available on the immediate effects of TENS in masticatory muscle pain related to temporomandibular disorders (TMDs). The present study aimed to evaluate the immediate effects of TENS treatment on TMD-related muscle pain. Thirty-six patients with TMD-related muscle pain and 39 healthy subjects served as TMD and control groups, respectively. For objective evaluations, maximum mouth opening, and maximum bite force were measured before and after TENS. The pain intensity was assessed according to a 100-mm visual analog scale (VAS). TENS was applied to painful muscles for 20 min with frequencies of 100–200 Hz. The treatment outcome was evaluated using Global Rating of Change (GRC) scales. In the TMD group, VAS values significantly decreased after TENS. Although there was significant increase in the maximum mouth opening after TENS for only TMD group, the maximum bite force of both groups was significantly greater after TENS. According to GRC scales, one patient with TMD-related muscle pain expressed negative feelings after TENS. Conclusively, TENS treatment might quickly relieve pain in masticatory muscles and improve masticatory functions in patients with TMD-related muscle pain.

Evaluation of the measurement precision and accuracy in the dental CAD/CAM system

The purpose of this study is to investigate the precision and trueness of the occlusal contact record obtained with a dental CAD/CAM device (ARCTICA). Sandblasted spherical steel balls with diameters of 10-20 mm were measured using ARCTICA and a three-dimensional measurement device (FN503). The radius of each steel ball was calculated from the measured value and the difference between the measured and nominal values was obtained. Upper/lower dental arch casts were measured and processed for occlusal contact image creation using both devices. The graphical images of the occlusal contacts at the intercuspal position obtained from both systems and an occlusal analysis device (BE-1) were compared with the occlusal contact area. Excellent correlation was observed between the measurement results of ARCTICA and FN503 (p<0.001, R²: 0.99). The occlusal contact areas were 186.0 mm² (ARCTICA), 192.8 mm² (FN503), and 196.1 mm² (BE-1). This study showed that ARCTICA is capable of conducting highly accurate measurements and generating a graphical image of occlusal contacts with good reliability.

Comparative analysis of education, awareness, and knowledge of dentists and physical therapists in the treatment of temporomandibular disorders

OBJECTIVE

To compare the education, awareness, and knowledge of Filipino dentists and physical therapists (PTs) in terms of temporomandibular disorders (TMDs).

METHODS

A 30-item structured online questionnaire was given to recruited PTs and dentists from January 2019 to December 2019. Welch's t-test was used to compare the education, awareness, and knowledge of health professionals. Brown-Forsythe and Welch ANOVA with Games-Howell post hoc were used to compare test scores across the knowledge components.

RESULTS

Of the 620 professionals, 46.67% dentists and 6.38% PTs had training in TMD. Professionals with more years of experience and who had previous TMD training were more aware of TMD management. Both dentists and PTs showed the lowest knowledge in TMD pathophysiology.

DISCUSSION

This study showed high awareness but low education and knowledge of Filipino dentists and PTs in TMD management. Improving the educational curriculum and refining the training given by accredited professional organizations is suggested.

Analysis of the Filipinos' Interest in Searching Online for Oral Cancer

Objective:

This study analyzed the health-seeking behavior of Filipinos through relative search volume in Google Trends using oral cancer, mouth cancer, tongue cancer, gum cancer, and lip cancer as predetermined search terms.

Methods:

Comma-separated values files containing relative search volumes of search trends pertaining to oral cancer from 2009 to 2019 were assessed. Brown-Forsythe one-way ANOVA was used to measure differences of oral cancer between years and among months. Repeated measures two-way ANOVA measured differences among the searches for mouth cancer, tongue cancer, gum cancer, and lip cancer through the years. Time series models were fitted and used to forecast search interests.

Results:

The results revealed that interests in oral cancer were significantly higher in 2019 (43.75±5.5, p<0.05) compared to 2009 (29.0 ± 6.7). In terms of months, searches were higher in February (45.0 ± 6.6) compared to May (24.8 ± 3.4, p=0.015), June (25.3 ± 4.4, p=0.020), and December (26.5 ± 4.0, p=0.038). Search interests for gum cancer and lip cancer remained significantly lower from 2011 to 2019, and tongue cancer from 2016 to 2018 but approximated mouth cancer in 2019. The forecast shows mouth cancer (31.67%), tongue cancer (23.75%), and lip cancer (3.83%) fluctuating through the year, while gum cancer (8%) will remain steady in 2020.

Conclusion:

Health-seeking behavior through search trends show an increased interest in oral cancer in 2019 and during February. Search interests will fluctuate in 2020, but at the end of the year will decrease for mouth cancer and tongue cancer, will increase for lip cancer, and will remain steady for gum cancer.

Three-dimensional periodontal tissue regeneration using a bone-ligament complex cell sheet

Periodontal tissue is a distinctive tissue structure composed three-dimensionally of cementum, periodontal ligament (PDL) and alveolar bone. Severe periodontal diseases cause fundamental problems for oral function and general health, and conventional dental treatments are insufficient for healing to healthy periodontal tissue. Cell sheet technology has been used in many tissue regenerations, including periodontal tissue, to transplant appropriate stem/progenitor cells for tissue regeneration of a target site as a uniform tissue. However, it is still difficult to construct a three-dimensional structure of complex tissue composed of multiple types of cells, and the transplantation of a single cell sheet cannot sufficiently regenerate a large-scale tissue injury. Here, we fabricated a three-dimensional complex cell sheet composed of a bone-ligament structure by layering PDL cells and osteoblast-like cells on a temperature responsive culture dish. Following ectopic and orthotopic transplantation, only the complex cell sheet group was demonstrated to anatomically regenerate the bone-ligament structure along with the functional connection of PDL-like fibers to the tooth root and alveolar bone. This study represents successful three-dimensional tissue regeneration of a large-scale tissue injury using a bioengineered tissue designed to simulate the anatomical structure.