Differences in Brain Volume by Tooth Loss and Cognitive Function in Older Japanese Adults.

BACKGROUND: We investigated the association between tooth loss and structural brain volume and its mediating effect on the association between tooth loss and cognitive function in older Japanese. METHODS: A cross-sectional study was conducted by using the data of 494 randomly sampled community-dwelling individuals aged 65-84 years living in Tokamachi City, Japan. Total brain volume (TBV), gray matter volume (GMV), white matter volume (WMV), and hippocampal volume (HV) were measured with magnetic resonance imaging. The association of self-reported number of teeth (≥20, 1-19, and 0) with cognitive function assessed with the Japanese version of the Quick Mild Cognitive Impairment screen and structural brain volume was examined. Causal mediation analysis was performed to evaluate the mediating effect of structural brain volume. Age, sex, socioeconomic status, health behavior, comorbid conditions, and total intracranial volume were adjusted. RESULTS: Respondents with no teeth showed lower cognitive function (coefficient = -4.01; 95% confidence interval [CI]: -7.19, -0.82), lower TBV (coefficient = -10.34; 95% CI: -22.84, 2.17), and lower GMV (coefficient = -6.92; 95% CI: -14.84, 0.99) than those with ≥20 teeth (P for trends were 0.003, 0.035, and 0.047, respectively). The number of teeth was not significantly associated with WMV or HV. GMV showed a significant mediating effect on the association between the number of teeth and cognitive function (coefficient = -0.38; 95% CI: -1.14, -0.002, corresponding to 9.0% of the total effect), whereas TBV did not. CONCLUSIONS: GMV was suggested to mediate the relationship between tooth loss and lower cognitive function.

[Use of integral indices in the assessment of bucсal cytology in health and in the oral cavity pathology.]

Cytological analysis of buccal epithelium (BE) - the buccal cytogram allows to select about 20 parameters reflecting cytogenetic, inflammatory, proliferative and other disorders in epithelial cells used for biomonitoring and laboratory diagnostics. In order to simplify and increase the information content of this study, we conducted a comparative analysis of various integral indices when interpreting the buccal cytogram. 40 practically healthy volunteers, 35 patients with chronic periodontitis, 22 patients with chronic gingivitis and 20 patients with partial loss of teeth were examined. The obtained data revealed an increase in the degree of disorders of proliferation and apoptosis, their ratio as the inflammation increased from gingival tissue lesions to inflammation periodontal tissue. In assessing the condition of the mucous membranes in chronic gingivitis, the apoptosis index turned out to be more informative.In chronic periodontitis the index of cytogenetic disorders is indicative. In this category of patients, the accumulation index of cytogenetic disorders did not have any advantages over the others, and the reparative index was less informative.

Alveolar bone resorption after primary tooth loss has a negative impact on straightforward implant installation in patients with agenesis of the lower second premolar.

OBJECTIVES: To compare the alveolar bone dimensions in patients with lower second premolar (P2) agenesis prior to and after primary molar loss on CT scans, and assess the possibility for straightforward implant placement. METHODS: Alveolar bone dimensions were evaluated on 150 mandibular CT scans in three groups: (i) agenesis of P2, with the primary tooth in situ, and regularly erupted first premolar (P1) and molar (M1) (AW); (ii) agenesis of P2, without the primary tooth in situ for ≥3 m, but regularly erupted P1 and M1 (AWO); and (iii) P1, P2, and M1 regularly erupted (CTR). The possibility of straightforward placement of an implant 3.5 or 4.3 mm in Ø × 10 mm long was digitally simulated and compared to the actually performed treatment. RESULTS: Buccolingual width (7.3 ± 2.0 mm) at the coronal aspect of the ridge in the AWO group was statistically significantly smaller comparing with both the AW (9.2 ± 1.4 mm) and the CTR (9.5 ± 1.1 mm) group; width reduction appeared to be mainly due to "collapse" of the buccal aspect of the ridge. Simulated straightforward placement of implants with a diameter of 3.5 or 4.3 mm was possible in 62% and 56% of the cases in the AWO vs. 86% and 84% in the AW group (p = .006 and .002, respectively). Straightforward implant placement was actually possible in all patients (22) in the AW group, while 28% (11 of 39) of the patients in the AWO group needed additional hard tissue augmentation. CONCLUSIONS: Significant dimensional differences exist in the alveolar ridge, especially in the coronal part, at lower P2 agenesis sites missing the primary tooth for ≥3 m, when compared to P2 agenesis sites with the primary tooth in situ. It seems thus reasonable to advise that the primary second molar should be kept as long as possible, in order to facilitate straightforward implant installation and reduce the probability of additional bone augmentation procedures.

Vertical subclassification predicts survival of molars with class II furcation involvement during supportive periodontal care.

BACKGROUND: Furcation involvement is a major predictor of tooth survival. Focus has so far been on the predictive value of the horizontal component of furcation involvement. Residual periodontal support on each of the roots is likely to play a major role on retention of the furcated molar. Aim of this clinical audit study was to preliminarily assess the impact of vertical subclassification on tooth retention. METHODS: Tooth retention of class II furcated molars in 200 consecutive patients compliant with periodontal supportive care for a minimum of 10 years was retrospectively evaluated in a single practice. Randomly selected furcated molars were retrospectively diagnosed in terms of vertical subclassification (residual periodontal support on the most compromised root), and time to tooth extraction/loss was determined in clinical records. Kaplan-Meier survival curves were constructed. RESULTS: Ten-year survival of molar with class II furcation involvement was 52.5%. Survival was 91% for subclass A, 67% for subclass B and 23% for subclass C. Mean years of survival were 9.5-10.1, 8.5-9.3 and 6-7.3 for subclasses A, B and C, respectively. Tests of equality of the survival distributions showed highly significant differences in all portions of the curve (p < .001). Stratified analyses by smoking showed significant differences for the two groups (p < .001). Hazard rates for tooth extraction/loss were 4.2 and 14.7 for subclasses B and C, respectively. CONCLUSIONS: Residual periodontal support assessed as vertical subclassification of furcation involvement seems to be a good predictor of survival of molar with class II horizontal furcation. This has implication for prognosis, treatment planning and development of effective molar retention strategies.

Tooth loss and general quality of life in dentate adults from Southern Brazil.

PURPOSE: This study aimed to estimate the association between the number of teeth and general quality of life in adults. METHODS: A population-based study was conducted with 1720 individuals aged 20-59 years residing in Florianópolis, Brazil, in 2009. Data were collected at participants' households using a structured questionnaire. In 2012, a second wave was undertaken with 1222 individuals. Oral examinations were performed for number of teeth, prevalence of functional dentition (≥21 natural teeth), and shortened dental arch (SDA), which were considered the main exposures. General quality of life was the outcome and was assessed with the WHO Abbreviated Instrument for Quality of Life (WHOQOL-BREF). Covariates included sociodemographic factors, health-related behaviors, and chronic diseases. Multivariable linear regression models were performed to test the associations between the main exposures and the outcome adjusted for covariates. RESULTS: In 2012, 1222 individuals participated in the study (response rate = 71.1%). Having more teeth was associated with greater scores on physical domain of the WHOQOL-BREF [ß = 0.24 (95% CI 0.01; 0.46)] after adjustment for covariates. Absence of functional dentition was associated with lower scores on the physical domain [ß = -3.94 (95% CI -7.40; -0.48)] in the adjusted analysis. There was no association between both SDA definitions and the domains of general quality of life. CONCLUSIONS: Oral health as measured by tooth loss was associated with negative impacts on general quality of life assessed by the WHOQOL-BREF. There was a lack of evidence that SDA is a condition that negatively affects general quality of life.

A test of a skeletal ageing method based on resorption of the alveolar crest following tooth loss using a skeletal population of documented age at death.

OBJECTIVES: Resorption of the alveolar process occurs following tooth loss, and appears to continue for a prolonged period. Previous study (Mays, ) with a known-age collection of human remains suggested the potential of this phenomenon for age estimation in remains of adults who have lost one or more molar teeth. This article tests this ageing technique on another known age group, and attempts to evaluate the impact of some extraneous factors on the method. MATERIALS AND METHODS: The study group comprises adult skeletons (N = 110) of documented age at death from 18th to 19th century London. It examines the relationship between a previously described standardized measure of posterior corpus height (SPCH) in mandibles showing loss of one or more molars. The potential influence of a general tendency to form or lose bone (identified by the presence of ossification into the anterior longitudinal ligament of the spine and cortical thickness at the metacarpal) and (for females) parity are also investigated. RESULTS: Negative age correlation was found for SPCH in females but not in males. In females, the age-association was weaker, and the rate of loss slower, than in a previously studied 19th century European population. None of the other factors investigated showed a relationship with SPCH. DISCUSSION: As with other bony age indicators, the relationship between SPCH and age varies in different populations. Further work is needed to evaluate the extraneous factors that affect the relationship with age.

Maxillary Sinus Dimensions Decrease as Age and Tooth Loss Increase.

OBJECTIVE: To investigate the correlation between patient-dependent variables and dimensional variations of the maxillary sinus. METHODS: In this cross-sectional study, a total of 394 individual cone-beam computed tomography scans were evaluated by one calibrated examiner to measure the total volume of the maxillary sinus, the distance between the medial and the lateral walls at 5, 10, and 15 mm vertically from the sinus floor, the height of septa (if present), and the height of the maxillary sinus cavity from both the alveolar crest and the sinus floor to the meatus. Recorded patient-dependent variables were age, gender, and edentulism status. RESULTS: Total maxillary sinus volume was significantly smaller in completely and partially edentulous patients than in dentate subjects. This finding was influenced by age, as older patients exhibited less volume, regardless of gender and edentulism status. Age showed an indirect correlation with the distance to the meatus, the sinus volume, and the mediolateral dimensions. Additionally, the prevalence of accessory meatus in this population was 29.19%. CONCLUSIONS: The dimensions of the maxillary sinus are influenced by age and edentulism status being reduced by aging and tooth loss.

Evaluation of Single Tooth Loss to Maxillary Sinus and Surrounding Bone Anatomy With Cone-Beam Computed Tomography: A Multicenter Study.

BACKGROUND: Posterior maxillary tooth loss may complicate the implant treatment due to the alterations in alveolar anatomy and maxillary sinus pneumatization. This study aimed to comprehensively examine the anatomical structure of this region from cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: The posterior maxilla regions with single tooth loss were analyzed by dividing the variables into 3 subgroups from images of 597 patients chosen from 1160 CBCTs. Variables associated with sinus membrane (SM), sinus dimensions, ostium, septa, sinus neighborhood, alveolar bone height (ABH) and width (RW), posterior superior alveolar artery (PSAA), and adjacent roots were evaluated. RESULTS: The majority of the patients demonstrated 0 to 5 mm membrane thickness. Irregular SM thickening was lower for female patients. While females showed higher number of narrow sinus, males had higher RW than females. Sinus augmentation classification showed negative correlation with ABH, root-tip sinus floor and edentulous site classification. Posterior septa height was correlated with number of septa and ABH. PSAA diameter and location were also correlated between each other. CONCLUSION: The present results define formation of a sinus space with 11 mm coronal and 16 mm apical width after single tooth loss. A flat or semispherical thickening around 4 mm is usual in most cases with 51% possibility of anterior septum existence. A ridge anatomy, around 7.5 mm ABH and 7.2 to 9.3 RW from coronal to apical, complements this anatomy. Further studies are needed to clarify the reasons behind the SM and crestal anatomy variations between genders.

Oral health and risk of colorectal cancer: results from three cohort studies and a meta-analysis.

BACKGROUND: While studies have shown that poor oral health status may increase the risk of cancer, evidence of a specific association with the risk of colorectal cancer (CRC) is inconclusive. We evaluated the association between oral health and CRC risk using data from three large cohorts: the Shanghai Men's Health Study (SMHS), the Shanghai Women's Health Study (SWHS), and the Southern Community Cohort Study (SCCS), and carried out a meta-analysis of results from other relevant published studies. PATIENTS AND METHODS: This study applied a nested case-control study design and included 825 cases/3298 controls from the SMHS/SWHS and 238 cases/2258 controls from the SCCS. The association between oral health status (i.e. tooth loss/tooth decay) and CRC risk was assessed using conditional logistic regression models. A meta-analysis was carried out based on results from the present study and three published studies. RESULTS: We found that tooth loss was not associated with increased risk of CRC. ORs and respective 95% CIs associated with loss of 1-5, 6-10, and >10 teeth compared with those with full teeth are 0.87 (0.69-1.10), 0.93 (0.70-1.24), and 0.85 (0.66-1.11) among SMHS/SWHS participants; and 1.13 (0.72-1.79), 0.87 (0.52-1.43), and 1.00 (0.63-1.58) for those with loss of 1-4, 5-10, and >10 teeth among SCCS participants. Data regarding tooth decay were available in the SCCS, but were not associated with CRC risk. Meta-analysis confirmed the null association between tooth loss/periodontal disease and CRC risk (OR 1.05, 95% CI 0.86-1.29). CONCLUSION: In this analysis of three cohorts and a meta-analysis, we found no evidence supporting an association between oral health and CRC risk.

Molar loss and powder diet leads to memory deficit and modifies the mRNA expression of brain-derived neurotrophic factor in the hippocampus of adult mice.

BACKGROUND: It is known that tooth loss is known to be a risk factor for Alzheimer's disease and soft diet feeding induces memory impairment. Recent studies have shown that brain-derived neurotrophic factor (BDNF) is associated with tooth loss or soft diet in young animal model, and that BDNF expression is decreased in patients with Alzheimer's disease. However, single or combined effect of tooth loss and/or soft diet on brain function has not fully understood. Here we examined the effect of molar loss and powder diet on memory ability and the expression of BDNF mRNA in the hippocampus of adult C57BL/6J mice. Twenty eight-weeks-old C57BL/6J mice were divided into intact molar group and extracted molar group. They were randomly divided into the I/S group (Intact upper molar teeth/Solid diet feeding), the E/S group (Extracted upper molar teeth/Solid diet feeding), the I/P group (Intact upper molar teeth/Powder diet feeding), and the E/P group (Extracted upper molar teeth/Powder diet feeding). The observation periods were 4 and 16-week. To analyze the memory ability, the step-through passive avoidance test was conducted. BDNF-related mRNA in the hippocampus was analyzed by real-time polymerase chain reaction (RT-PCR). RESULTS: At 4 weeks later, we performed memory test and isolated brains to analyze. There were no differences in memory function and BDNF mRNA level between these four groups. However, at 16 weeks later, E/S and E/P group showed memory impairment, and decreased level of BDNF mRNA. Whereas, the powder diet had no effect on memory function and BDNF mRNA level even at 16 weeks later. CONCLUSIONS: These results suggest that the effect of molar loss and powder diet on memory function and BDNF mRNA levels were different, molar loss may have a greater long-term effect on memory ability than powder diet does.

A bioarchaeological analysis of oral and physiological health on the south coast of New Guinea.

OBJECTIVES: The south coast of New Guinea has a complex prehistory known for its exchange systems that linked distinct cultural groups living along the coast, inland, and on offshore islands. Here we compare the palaeohealth of two relatively contemporaneous skeletal samples from the south coast of New Guinea (850-200 BP) that were from two ecologically different sites (one inland and one offshore island) and likely represent distinct cultural groups. We aim to elucidate health patterns that may provide information about the specific lifeways and quality of life of each community. MATERIALS AND METHODS: Oral conditions (caries, calculus, alveolar lesions, and antemortem tooth loss [AMTL]) were analyzed macroscopically to assess possible intra- and inter-population variation in oral and physiological health. The frequency of linear enamel hypoplasia (LEH) was also used as a nonspecific indicator of stress to assess childhood health at each site. RESULTS: The inhabitants from the small offshore island of Motupore, thought to be associated with Austronesian-speaking Motu tribes, displayed different patterns of oral pathological conditions (more carious lesions on the tooth crown and calculus) and LEH (lower frequencies) compared with inland people residing at the site of Nebira. DISCUSSION: It is suggested that the causes for the variation in oral and physiological health were likely multifactorial and potentially associated with variables such as the ecological and geographical settings of the sites, cultural differences, infectious disease, differential fertility and, potentially, diet. This research provides previously unknown information about possible culturally-moderated practices that affected health in the past. Am J Phys Anthropol 160:414-426, 2016. © 2016 Wiley Periodicals, Inc.

Maxillary Sinus Dimensions With Respect to the Posterior Superior Alveolar Artery Decrease With Tooth Loss.

BACKGROUND: The posterior superior alveolar (PSA) artery is frequently encountered in the area where the lateral osteotomy is performed during direct sinus augmentation procedures. OBJECTIVE: To investigate the correlation between patient-dependent variables and measurements related to PSA using cone beam computed tomography (CBCT) data. METHODS: Three hundred ninety-four CBCT scans were evaluated to assess the PSA artery diameter and distances to the sinus floor and to alveolar crest. Patient's age, gender, and edentulism status were recorded. RESULTS: The PSA artery tends to be wider in older patients. Distances to the sinus floor or the alveolar crest tend to be shorter in women and in partially and completely edentulous patients. Also, as those distances decrease, the mediolateral width of the sinus increases. CONCLUSION: Tooth loss leads to maxillary sinus vertical collapse with respect to the PSA artery. The position of the artery is stable; so, the mediolateral dimensions at different heights from the floor increase. PRACTICAL IMPLICATIONS: The reduced distances from the PSA to the sinus floor and the alveolar crest in edentulous patients potentially increase the risk of injury during maxillary sinus lift. Additionally, when the distance to the sinus floor decreases, the mediolateral dimensions of the sinus at different heights increase, which may complicate the technique and challenge the outcomes.

Tooth loss might not alter molecular pathogenesis in an aged transgenic Alzheimer's disease model mouse.

BACKGROUND AND OBJECTIVE: Previous studies have reported that tooth loss is a risk factor of Alzheimer's disease (AD). However, the association between tooth loss and cognition and the impact of tooth loss on the molecular pathogenesis of AD remain elusive. In this study, we tested the effect of tooth loss on learning and memory and on the molecular pathogenesis of AD in an aged AD model mice. MATERIALS AND METHODS: We divided 14-month-old amyloid precursor protein (APP) transgenic mice, an AD model mouse line, into upper molar extracted group (experimental) and molar intact group (control). At 18 months old, we analysed not only the changes of amyloid-beta (Aß), pyramidal cells in the brain but also the learning and memory ability with step-through passive avoidance test. RESULTS: The amount of Aß and the number of pyramidal cells in the hippocampus were not significantly different between the experimental and control group. Similarly, the difference of learning and memory ability could not be distinguished between the groups. CONCLUSION: Neither molecular pathogenesis of AD nor associated learning and memory were aggravated by tooth loss in these mice. The limited results of this study which used the aged mice may help the dental profession to plan and explain treatments to patients with AD, which must be designed while taking into account the severity of the AD symptoms.

[ANATOMICAL CORRELATIONS OF THE PALATO-ALVEOLAR COMPLEXES AND MAXILLARY SINUSES IN ADULT PERSONS].

To detect the anatomical correlations between the form of the palato-alveolar complex and the shape and degree of pneumatization of the maxillary sinuses, skull frontal saw cuts obtained from 60 adult persons were studied at the level of the second molars. The form of the palato-alveolar complex was found to change significantly with the loss of teeth. Thus the palato-alveolar complex with well expressed alveolar process of the upper jaw and high palatal vault more often corresponded to the maxillarysinus of a trihedral or uncertain form with the varying degrees of pneumatization. The palato-alveolar complex with a considerable atrophy of an alveolar process of the upper jaw and the flat palate was accompanied by the hyperpneumatitized sinuses of a tetrahedral form, while the transitional form of the complex which was observed in cases of partial loss of the teeth, was combined with the asymmetry of the form and degree of a pneumatization of the sinuses. These correlations are important for oral and maxillofacial surgery and dentistry.

[The paper summarizes data on laboratory and clinical assessment of Corega dent Laboratory and clinical analysis of Corega denture adhesive cream mechanical properties]. / Analiz fiziko-mekhanicheskikh svoistv krema dlya fiksatsii s''emnykh zubnykh protezov korega v laboratorii i klinicheskoi praktike.

The paper summarizes data on laboratory and clinical assessment of Corega denture adhesive cream adhesive properties: adhesion strength and time of adhesive material fixing. Clinical assessment was based on Ulitovsky-Leontyev denture fixation index evaluated in 18 edentulous patients with full removable dentures 1 and 12 months after denture manufacturing. After one year of evaluation denture fixation in patients using Corega denture adhesive cream was 8-15% better (depending on alveolar bed anatomy) than in controls proving that Corega improves full denture adaptation to physiological atrophy of alveolar bone.

Sound analysis of a musical performance to evaluate prosthodontic treatment for a clarinet player.

Some dental patients use the orofacial region to play wind instruments; however, musical performance has not been objectively evaluated following prosthodontic treatment in such patients. The purpose of this report was to describe prosthodontic treatment for a clarinet player using sound analysis. The patient required a removable partial denture for his maxillary anterior teeth. Sound analysis was performed before and after denture adjustment, and the patient completed a questionnaire regarding his perceptions while playing his clarinet. After adjustment, the denture showed better performance, and patient satisfaction increased compared with that before adjustment.

Resorption of mandibular alveolar bone following loss of molar teeth and its relationship to age at death in a human skeletal population.

Estimating adult age at death in skeletal remains is problematic, particularly in older adults. Molar wear is arguably the most reliable ageing technique for palaeopopulations, but many older adult skeletons have lost their molar teeth ante mortem, precluding its application. Resorption of the alveolar process occurs following tooth loss, and this appears to continue for a prolonged period. The current work investigates the relationship of this process to individual age in a nineteenth century AD European archaeological skeletal series of known age at death (N = 92 individuals), and discusses its potential as an age indicator. Mandibular corpus height was measured at the different molar positions. In females, reduction of corpus height with age was found at molar positions showing ante mortem loss. In both sexes, a relationship was found between age and a simple composite measure of corpus height in the molar region in those showing ante mortem loss of one or more mandibular molars. The correlation was stronger in females (r = -0.74) than in males (r = -0.49), appeared approximately linear, and continued into the ninth decade, the oldest age group in the study material. The results suggest that investigation of height of the posterior part of the mandibular corpus as a skeletal age indicator for individuals that have lost one or more molar teeth is merited in other palaeopopulations.

Influences of multiple tooth-loss on signal travel in the insular cortex of rats.

The insular cortex (IC) processes various kinds of sensory and emotional information. Multiple tooth-loss induces impairment of oral sensory and motor functions, which might result in the up- or down-regulation of signal processing in the IC. In the present study, we investigated how multiple tooth-loss affects neural activities in the IC. Slices of the IC were prepared from control (untreated) rats and rats raised following the loss of their upper molar teeth, and optical recordings with voltage-sensitive dye were made. Electrical stimulation was delivered to the agranular IC (AIC). The velocity of optical signal from the AIC to the granular IC (GIC) decreased in multiple tooth-loss rats compared with control rats. Field potentials from the GIC were recorded. Onset times of evoked response at the GIC recorded from multiple tooth-loss rats were prolonged compared with those recorded from control rats, suggesting that signal velocity in multiple tooth-loss rats had decreased. A reduced signal velocity was accompanied by neuronal loss in the GIC, which was confirmed by counting the cell numbers on Nissl-stained sections. Thus, multiple tooth-loss may have influences on the GIC where signal processing speed decreases.

Treatment of an asymmetric malocclusion: a case report.

AIM: This case report describes an adult female patient who presented with dental asymmetry associated with bilaterally missing lower first molars, accompanied by extruded and mesially-tipped lower second and third molars. Masticatory dysfunction and temporomandibular joint (TMJ) pain were present during mouth opening and likely related to a posteriorly positioned condyle and anterior disc displacement with reduction. METHODS: Orthodontic treatment consisted of occlusal plane levelling and mandibular repositioning, achieved using a Multiloop Edgewise Archwire (MEAW) technique. Differential MEAW activation on each side and temporary occlusal composite bite blocks on the lower left third molar were necessary to increase the vertical dimension of the Class II side, which allowed extrusion of the left premolars to a Class I relationship. RESULTS: The bilateral uprighting of the second and third molars was achieved by tip-back wire activation to level the occlusal plane and intrude these teeth. Elastics worn vertically on the right side and Class II elastics on the left side facilitated occlusal correction. Dental implants for fixed prosthetic rehabilitation of the missing lower left first molar were placed to stabilise the posterior occlusion. Articular disc recovery removed TMJ symptoms and the case was finished with stable sagittal and vertical occlusal relationships. CONCLUSION: Successful management of a canted occlusal plane and the stabilisation of the posterior occlusion, resulted in a recovery of a displaced articular disc and improvement of facial symmetry.