Correlation between periodontal status and biting ability in Chinese adult population

Evaluation of the thickness of masticatory muscles in patients with chronic periodontitis by ultrasonography

OBJECTIVES

Periodontitis is one of the most common chronic inflammatory diseases. It causes changes in the biting abilities of individuals. However, periodontal treatment has positive effects on masticatory function. The aim of this study is to determine the effect of periodontitis and periodontal treatment on masticatory abilities by measuring masseter and temporal muscle thicknesses with ultrasonography before and after periodontal treatment in chronic periodontitis patients.

METHODS

The patients included in the study were determined by clinical and radiological examination. The thickness of the masseter and temporal muscles of the patients were measured by ultrasonography. Periodontal measurements and treatments of the patients were completed by a single physician. IBM SPSS 20.0 (IBM Corp., Armonk, NY) statistical program was used for statistical analysis.

RESULTS

A statistically significant difference was found between the values of periodontal measurements before and after treatment (p<0.05). In the ultrasonography measurements of the thickness of masseter and anterior temporal muscles, a statistically significant increase was observed in both rest and contraction values at all time intervals (p<0.05). Muscle thicknesses of male patients were higher than female patients.

CONCLUSIONS

Periodontitis negatively affects the masticatory performance of individuals. Chronic periodontitis patients should be referred for periodontal treatment without wasting time.

Periodontal Clinical Parameters as a Predictor of Bite Force: A Cross-Sectional Study

OBJECTIVE

To investigate the correlation of periodontal parameters and bite force in different stages of periodontitis after phase I periodontal therapy.

METHODS

Periodontal clinical parameters such as mobility, attachment loss, gingival recession, and percentage of bone remaining were recorded at the mandibular first molar region after phase I therapy in subjects categorized according to the stage of periodontitis. Corresponding bite force was recorded at the first mandibular molar region using a bite force device after phase I therapy. ANOVA test was used to assess the significant difference among different groups. Pearson correlation coefficient was used to assess the correlation between measured variables.

RESULTS

The ANOVA test represents that there is no statistical significant difference between the bite force in stage I, stage II, and stage III type of periodontitis. A strong positive correlation was found (r = 0.537) between bite force and percentage of remaining alveolar bone support whereas negative correlation was observed in measured parameters such as mobility (r = -0.0181), attachment loss (r = -0.608), and gingival recession (r = -0.435).

CONCLUSION

Among all periodontal clinical parameters, the percentage of remaining alveolar bone is the strong predictor of bite force and mobility; attachment loss and gingival recession cannot predict the bite force in the first molar region. Bite force is variable in different stages of periodontitis.

Development of a bite force transducer for measuring maximum voluntary bite forces between individual opposing tooth surfaces

Bite forces are studied in order to understand a wide range of factors pertaining to the mastication system. Various strain gauge transducers have been employed to measure bite forces, with several descriptions of these available in the literature; unfortunately, many reports provide insufficient detail to enable accurate reproduction. The aim of this project was to develop a bite force transducer with the capability of measuring maximum voluntary bite forces between individual opposing tooth surfaces. Furthermore, in an attempt to address the issue of vague device descriptions in the available literature, a detailed account of the transducer development has been included. A novel strain gauge transducer was designed and built. Bite forces of forty individuals were measured to verify the capabilities and clinical application of the device.

Masseter muscle thickness and elasticity in periodontitis

This study aimed to compare the thickness and elasticity of the masseter muscle between patients with gingivitis and patients with periodontitis. A total of 124 patients (63 gingivitis, 61 chronic periodontitis) were recruited at the start of the study, but only 84 patients were declared as final participants. Patients were divided into two groups: (1) patients suffering from gingivitis and (2) those with generalized chronic periodontitis. Clinical (PI, plaque index; GI, gingival index; PD, probing depth; CAL, clinical attachment loss; and BOP, bleeding on probing scores) and ultrasonographic (thickness and elasticity of the masseter muscle) measurements of periodontitis were performed. There were no significant differences in gender, age, body mass index, education status, income level, or marital status between the two groups (P > 0.05). The mean age ± SD for the gingivitis and periodontitis groups was 39.5 ± 10.8 years and 44.8 ± 8.8 years, respectively. There were significant differences between the two groups in the number of PI, GI, PD, CAL, and BOP scores. There were significant differences between the two groups when thickness of masseter during contraction and at rest was taken into account. The gingivitis group had significantly thicker masseter during both contraction and rest. On the other hand, when the elasticity of the masseter was evaluated, there were no significant differences found between the two groups and two sides for each group. Masseter muscle thickness in the periodontitis group was found to be decreased compared with that in the gingivitis group. Furthermore, loss of periodontal tissues due to periodontitis reduces the masticatory ability.

Masticatory satisfaction, ability, and performance in partially dentate patients after periodontal therapy

Abstract Introduction Understanding the effects of periodontal therapy is essential in performance and satisfaction of partially dentate patients. Objective To assess the effect of subgingival periodontal treatment in performance and masticatory satisfaction and ability as reported by partially dentate patients with untreated chronic periodontitis. Materials and method Patients were given nonsurgical periodontal treatment and masticatory satisfaction, ability, and performance were evaluated before and after treatment. Performance was assessed based on sieving chewed standardized chewable material, while satisfaction and ability were analyzed using a questionnaire based on OHIP-EDENT. Result Mean numbers of functional tooth units were 10.36 ± 1.43 anterior and 6.73 ± 0.79 posterior teeth. Masticatory performance did not vary significantly (p = 0.075), and mean particle sizes before and after treatment were 4.23 ± 1.84 mm and 3.90 ± 0.75 mm, respectively. Overall satisfaction and ability scores after treatment were higher (p > 0.05) compared with scores prior to the periodontal intervention. Conclusion Periodontal treatment improves masticatory satisfaction and ability with no effect on performance.

Unilateral Mastication Evaluated Using Asymmetric Functional Tooth Units as a Risk Indicator for Hearing Loss

BACKGROUND

Some previous studies reported hearing ability can be reduced by impaired masticatory ability, but there has been little evidence reported of an association between hearing loss and unilateral mastication. Therefore, this study aimed to investigate the relationship between unilateral mastication (UM), estimated from individual functional tooth units (FTUs), and hearing loss in a representative sample of Korean adults.

METHODS

The analyzed data were obtained from 1,773 adults aged 40-89 years who participated in Korean national survey. Hearing loss was defined as a pure-tone average of >25 dB at frequencies of 0.5, 1, 2, and 4 kHz in either ear. In each subject, UM was calculated as the difference in the sums of the FTU scores, which is an index of posterior tooth occlusion, on the two sides of the oral cavity. The scores were used to classify the UM into low, moderate, and high. The adjusted odds ratios (aORs) and their 95% confidence intervals (CIs) were calculated in multivariable logistic regression analyses.

RESULTS

When controlling for sociodemographic factors, the aOR for hearing loss was 3.12 (95% CI, 1.21-8.03) for high UM relative to low UM. This association remained in a fully-adjusted model containing factors related to noise exposure (aOR 2.88; 95% CI, 1.12-7.46).

CONCLUSION

Adults with high UM as measured using FTUs showed a higher occurrence of hearing loss than those with low UM.

Periodontal Ligament Stem Cells in the Periodontitis Microenvironment Are Sensitive to Static Mechanical Strain

During orthodontic treatment, periodontium remodeling of periodontitis patients under mechanical force was abnormal. We have previously confirmed the function impairment of periodontal ligament stem cells (PDLSCs) in the periodontitis microenvironment which might be involved in this pathological process. However, the response of PDLSCs in periodontitis microenvironment to mechanical force remains unclear. Therefore, in the present study, we introduced a Flexcell tension apparatus and investigated the response of PDLSCs obtained from periodontal tissues of periodontitis patients (PPDLSCs) and of those obtained from healthy periodontal tissues (HPDLSCs) to different magnitudes of static mechanical strain (SMS). PPDLSCs showed increased proliferation, decreased osteogenic activity, activated osteoclastogenesis, and greater secretion of inflammatory cytokines. Different magnitudes of SMS exerted distinct effects on HPDLSCs and PPDLSCs. An SMS of 12% induced optimal effects in HPDLSCs, including the highest proliferation, the best osteogenic ability, the lowest osteoclastogenesis, and the lowest secretion of inflammatory cytokines, while the optimal SMS for PPDLSCs was 8%. Excessive SMS damaged PPDLSCs function, including decreased proliferation, an imbalance between osteogenesis and osteoclastogenesis, and an activated inflammatory response. Our data suggest that PPDLSCs are more sensitive and less tolerant to SMS, and this may explain why mechanical force results in undesirable effects in periodontitis patients.

The impact of masticatory ability as evaluated by salivary flow rates on obesity in Japanese: The Toon health study

OBJECTIVE

This study examined the associations of masticatory ability evaluated by chewing-gum-stimulated salivary flow rate with anthropometric indices among a general Japanese population.

METHODS

In total, 921 Japanese men and women aged 30-79 years participated in this cross-sectional study. Saliva production was stimulated by 5 min of gum chewing, then collected; salivary flow rate was calculated as g/min. Overweight, abdominal obesity in terms of waist circumference (WC), and waist-hip ratio (WHR), and elevated skinfold thickness statuses were determined.

RESULTS

The multivariable odds ratio and 95% confidence intervals of overweight, abdominal obesity (WC, WHR), and elevated skinfold thickness status for highest vs. lowest quartile of salivary flow rate were 0.59 (0.37-0.95, P for trend = 0.02), 0.65 (0.43-0.98, P = 0.03), 0.54 (0.35-0.83, P < 0.01), and 0.61 (0.39-0.96, P < 0.01), respectively. The linear trends of multivariable-adjusted means of BMI, WC, WHR, and skinfold thickness according to quartiles of salivary flow rate did not vary after stratification by overweight status.

CONCLUSIONS

Higher stimulated salivary flow rate, a surrogate marker for mastication ability, was associated with lower prevalence of overweight, abdominal obesity (whether WC- or WHR-defined), and elevated skinfold thickness among the general Japanese population.

Mechanical stress enhances production of cytokines in human periodontal ligament cells induced by Porphyromonas gingivalis

OBJECTIVE

We have previously reported that human periodontal ligament (hPDL) cells produced many kinds of cytokines as a result of bacterial stimulation, including stimulation with Porphyromonas gingivalis (P. gingivalis). However, the effects of mechanical stress on cytokine production in hPDL cells stimulated by periodontopathogenic bacteria are not clearly understood. In this study, we investigated the effects of mechanical stress on the production of inflammatory cytokines in hPDL cells induced by stimulation with P. gingivalis.

METHODS

The hPDL cells were exposed to various levels of mechanical stress (1, 6, 10 and 50MPa) and costimulated with mechanical stress and P. gingivalis for 24h. Cytokine mRNA expressions were determined by RT-PCR. Cytokines in the culture supernatant were assessed by ELISA, and morphologic changes in hPDL cells were observed.

RESULTS

The expressions of interleukin (IL)-6, IL-8 and tumor necrosis factor-α mRNA were observed in hPDL cells after exposure to mechanical stress. Moreover, the production of IL-6 and IL-8 increased significantly after exposure to mechanical stress ranging from 1 to 10MPa. The amount of IL-8 in the culture supernatants of hPDL cells costimulated with P. gingivalis and mechanical stress was significantly higher than the expected additive amount. The morphology of hPDL cells did not change after exposure to 6MPa, but these cells were partly detached from the Petri dish after exposure to 50MPa.

CONCLUSIONS

These results suggest that local inflammation of the periodontal ligament may be induced mainly by periodontal bacteria, and mechanical stress may promote local inflammation.

Correlation between periodontal status and biting force in patients with chronic periodontitis during the maintenance phase of therapy

AIM

The association between periodontal status and biting force is unclear. The aim of this study was to investigate the relation between periodontal status and biting force in patients with chronic periodontitis during the maintenance phase of periodontal treatment.

MATERIAL AND METHODS

A total of 198 patients, who had entered a periodontal maintenance programme, were examined for the presence of restorations on the occlusal surface, probing pocket depth, clinical attachment loss (CAL), bleeding on probing, and mobility of teeth. Quantitative analysis of total biting force, occlusal contact area and biting pressure (defined by biting force per 1 mm(2) of occlusal contact area) was performed using microcapsular pressure-sensitive sheets.

RESULTS

A multiple stepwise regression analysis showed that total biting force and occlusal contact area were positively associated with the number of present teeth and negatively associated with female gender, mean CAL and mean probing pocket depth. Biting pressure was positively associated with CAL.

CONCLUSIONS

Reduced periodontal support was found to be associated with decreased total biting force and with increased biting pressure (defined as force per 1 mm(2) of occlusal contact area).

Influence of alveolar support on stress in periodontal structures

The influence of alveolar bone support on the functional capability of a tooth remains unclear. It was hypothesized that a reduction in alveolar support causes an increase of maximum stress in the periodontal structures. Mathematical models of the maxillary incisor to simulate in vivo tooth movement were constructed with periodontium of normal or reduced bone height, and normal or widened periodontal ligament (PDL) space. Under simulated bite force, the maximum tensile stress at the lingual cervical region in the PDL increased with bone height reduction, but decreased with PDL widening. The compressive stress at the cervical region in the cortical bone was no more than 22% of the yield strength of bone, and did not increase by the height reduction with widened PDL. The result suggests that the height reduction potentially causes mechanical damage to the PDL, but, of itself, is not likely to have a negative effect on the bone.

The effect of periodontitis on biting abilities

BACKGROUND

The aim of this study was to compare the biting abilities (bite force [BF] and occlusal contact area [OCA]) of chronic periodontitis patients with those of control patients with healthy periodontia by using pressure-sensitive sheets.

METHODS

The study population consisted of 20 patients with chronic periodontitis whose initial periodontal therapy was completed and 20 control subjects with healthy periodontia. Periodontitis was diagnosed by radiographs and measurements of probing depth and clinical attachment level. Pressure-sensitive sheets were used for the quantitative analysis of BF and OCA.

RESULTS

Both mean BF and OCA values were greater in the healthy control group compared to those of the study group. The differences between the groups were statistically significant at the 95% confidence level.

CONCLUSION

Reduced periodontal support in the absence of inflammation negatively affected biting abilities.

Impaired Masticatory Behavior in Subjects With Reduced Periodontal Tissue Support

BACKGROUND

Mechanoreceptors situated in the periodontal ligament provide detailed information about intensive and spatial aspects of tooth loads, which support the neural control of masticatory forces. We asked whether a reduced periodontal ligament due to periodontitis, and, thus, an altered mechanoreceptive innervation of the teeth, would affect masticatory behavior when subjects used incisors to hold and split food.

METHODS

We tested 11 subjects with reduced periodontal tissue support that rendered 30% to 70% alveolar bone loss for at least one pair of opposing anterior incisors. Forces were recorded when subjects used their affected incisors to hold half of a peanut for approximately 4 seconds and then split it. Age- and gender-matched healthy subjects served as the control group. None of the participants showed acute oral symptoms or massive periodontal inflammation.

RESULTS

The test group used greater force when holding food between the teeth (1.1+/-0.4 N [ mean+/-1 SD]) compared to the control group (0.4+/-0.2 N). Hold forces used by subjects in the test group were also more variable, both within and between trials. The increase in bite force applied to split the peanut was slower and more hesitant for subjects in the test group compared to the control group.

CONCLUSIONS

Reduced periodontal tissue support accompanies impaired regulation of masticatory forces. Faulty mechanoreceptive innervation of the periodontal ligament explains the elevated hold force, whereas a change in biting strategy due to the weakened support of the teeth may account for the more defensive food-splitting behavior.

The effect of periodontal surgery on bite force, occlusal contact area and bite pressure

BACKGROUND

Tooth mobility resulting from the loss of periodontal support or trauma induced by periodontal surgery may change the amount of bite force (BF) and bite pressure (BP) and number of occlusal contact areas (OCAs). The aim of the authors' study was to compare BF, BP and OCA of teeth with periodontal disease before and after periodontal surgery with similar values of healthy teeth.

METHODS

The authors performed quantitative analysis of BF, BP and OCA using a pressure measurement film. Ten patients with periodontitis who needed periodontal surgery served as the test group. The authors took measurements of BF, BP, OCA and mobility (using Miller's Mobility Index) just before surgery and at one, four and 12 weeks after surgery. They also measured clinical attachment levels (CAL) before surgery and 12 weeks after surgery. Ten subjects without periodontitis served as the control group.

RESULTS

Although BF and OCA increased the first week after periodontal surgery, analysis of variance (ANOVA) showed no statistically significant differences at a 95 percent confidence interval. There were statistically significant differences between first-week mobility and that at four and 12 weeks (P = .001). A factorial ANOVA showed significant interaction between BF and mobility (P < .05).

CONCLUSIONS

The authors' findings suggest that changes in BF, BP and OCA were not affected by periodontal surgery. However, mean mobility values and BF are correlated. Further investigations of this measurement method involving larger study populations and a longer follow-up period are needed.

CLINICAL IMPLICATIONS

It seems to be helpful to follow occlusal changes after periodontal surgery using a pressure measurement film. It also may be suggested that this measurement method could be used to evaluate the treatment prognosis.

Non-grafted sinus implants in periodontally compromised patients: a time-to-event analysis

This study reports the results of implant therapy involving a sinus membrane lift and of conventional implant therapy in 68 periodontally compromised patients treated between June 1990 and June 2002. Patients had at least two implants inserted, one of which was placed in the maxillary sinus region following fenestration of the lateral sinus wall and lifting of the sinus membrane. Two implant systems were used: a two-stage system (Astra) and a one-stage system (ITI). Annual follow-up visits included recording of plaque, probing pocket depth and measurement of the radiographic distance in millimeter from the implant shoulder to the alveolar crest. Survival analysis showed that the proportion of implants that had not been explanted after 5 years ranged between 88.7% for ITI sinus implants and 97% for ASTRA conventional implants. After 10 years, the proportion of implants remaining in situ ranged between 59% for ITI conventional implants and 97% for ASTRA conventional implants. Cox regression analyses showed that the factors influential for implant explantation were implant type (HR(ITI) = 2.8), implant length (HR(< or = 10 mm) = 3.1), patient being a smoker (HR(smoking) = 2.2) and patient having at least 20 natural teeth (HR(> or = 20 teeth) = 3.8). Our results demonstrate that sinus implants may be inserted with the same success as conventional implants in periodontally compromised patients.