The effect of culture on pain sensitivity

Cross‐cultural differences in pain sensitivity have been identified in pain‐free subjects as well as in chronic pain patients. The aim was to assess the impact of culture on psychophysical measures using mechanical and electrical stimuli in patients with temporomandibular disorder (TMD) pain and pain‐free matched controls in three cultures. This case–control study compared 122 female cases of chronic TMD pain (39 Saudis, 41 Swedes and 42 Italians) with equal numbers of age‐ and gender‐matched TMD‐free controls. Pressure pain threshold (PPT) and tolerance (PPTo) were measured over one hand and two masticatory muscles. Electrical perception threshold and electrical pain threshold (EPT) and tolerance (EPTo) were recorded between the thumb and index fingers. Italian females reported significantly lower PPT in the masseter muscle than other cultures (P < 0·001) and in the temporalis muscle than Saudis (P = 0·003). Swedes reported significantly higher PPT in the thenar muscle than other cultures (P = 0·017). Italians reported significantly lower PPTo in all muscles than Swedes (P ≤ 0·006) and in the masseter muscle than Saudis (P < 0·001). Italians reported significantly lower EPTo than other cultures (P = 0·01). Temporomandibular disorder cases, compared to TMD‐free controls, reported lower PPT and PPTo in all the three muscles (P < 0·001). This study found cultural differences between groups in the PPT, PPTo and EPTo. Overall, Italian females reported the highest sensitivity to both mechanical and electrical stimulation, while Swedes reported the lowest sensitivity. Mechanical pain thresholds differed more across cultures than did electrical pain thresholds. Cultural factors may influence response to type of pain test.     

Influence of intramuscular granisetron on experimentally induced muscle pain by acidic saline

The aim of this study was to investigate whether intramuscular administration of the 5‐HT₃ receptor antagonist granisetron reduces experimental muscle pain induced by repeated intramuscular injections of acidic saline into the masseter muscles. Twenty‐eight healthy and pain‐free volunteers, fourteen women and fourteen men participated in this randomized, double‐blind and placebo‐controlled study. After a screening examination and registration of the baseline pressure–pain threshold (PPT), the first simultaneous bilateral injections of 0·5 mL acidic saline (9 mg mL^?1, pH 3·3) into the masseter muscles were performed. Two days later, PPT and pain (VAS) were re‐assessed. The masseter muscle was then pre‐treated with 0·5 mL granisetron (Kytril^® 1 mg mL^?1 pH 5·3) on one side and control substance (isotonic saline, 9 mg mL^?1 pH 6) on the contralateral side. Two minutes thereafter a bilateral simultaneous injection of 0·5 mL acidic saline followed. The evoked pain intensity, pain duration, pain area and PPT were assessed. The volunteers returned 1 week later to re‐assess VAS and PPT. On the side pre‐treated with granisetron, the induced pain had significantly lower intensity and shorter duration (P < 0·05) compared with the side pre‐treated with control. A subgroup analysis showed that the effect of granisetron on pain duration was significant only in women (P < 0·001), while the effect on peak pain and pain area were significant in both sexes. The results showed no significant change in PPT. In conclusion, these results indicate that granisetron has a pain‐reducing effect on experimentally induced muscle pain by repeated acidic saline injection.     

Headache attributed to masticatory myofascial pain: impact on facial pain and pressure pain threshold

There is no clear evidence on how a headache attributed to temporomandibular disorder (TMD) can hinder the improvement of facial pain and masticatory muscle pain. The aim of this study was to measure the impact of a TMD‐attributed headache on masticatory myofascial (MMF) pain management. The sample was comprised of adults with MMF pain measured according to the revised research diagnostic criteria for temporomandibular disorders (RDC/TMD) and additionally diagnosed with (Group 1, n = 17) or without (Group 2, n = 20) a TMD‐attributed headache. Both groups received instructions on how to implement behavioural changes and use a stabilisation appliance for 5 months. The reported facial pain intensity (visual analogue scale – VAS) and pressure pain threshold (PPT – kgf cm^?2) of the anterior temporalis, masseter and right forearm were measured at three assessment time points. Two‐way anova was applied to the data, considering a 5% significance level. All groups had a reduction in their reported facial pain intensity (P < 0·001). Mean and standard deviation (SD) PPT values, from 1·33 (0·54) to 1·96 (1·06) kgf cm^?2 for the anterior temporalis in Group 1 (P = 0·016), and from 1·27 (0·35) to 1·72 (0·60) kgf cm^?2 for the masseter in Group 2 (P = 0·013), had significant improvement considering baseline versus the 5th‐month assessment. However, no differences between the groups were found (P > 0·100). A TMD‐attributed headache in patients with MMF pain does not negatively impact pain management, but does change the pattern for muscle pain improvement.     

The effects of manual therapy and exercise directed at the cervical spine on pain and pressure pain sensitivity in patients with myofascial temporomandibular disorders

Summary No studies have investigated the effects of the treatments directed at the cervical spine in patients with temporomandibular disorders (TMD). Our aim was to investigate the effects of joint mobilization and exercise directed at the cervical spine on pain intensity and pressure pain sensitivity in the muscles of mastication in patients with TMD. Nineteen patients (14 females), aged 19–57 years, with myofascial TMD were included. All patients received a total of 10 treatment session over a 5‐week period (twice per week). Treatment included manual therapy techniques and exercise directed at the cervical spine. Outcome measures included bilateral pressure pain threshold (PPT) levels over the masseter and temporalis muscles, active pain‐free mouth opening (mm) and pain (Visual Analogue Scale) and were all assessed pre‐intervention, 48 h after the last treatment (post‐intervention) and at 12‐week follow‐up period. Mixed‐model anovas were used to examine the effects of the intervention on each outcome measure. Within‐group effect sizes were calculated in order to assess clinical effect. The 2 × 3 mixed model anova revealed significant effect for time (F = 77·8; P < 0·001) but not for side (F = 0·2; P = 0·7) for changes in PPT over the masseter muscle and over the temporalis muscle (time: F = 66·8; P < 0·001; side: F = 0·07; P = 0·8). Post hoc revealed significant differences between pre‐intervention and both post‐intervention and follow‐up periods (P < 0·001) but not between post‐intervention and follow‐up period (P = 0·9) for both muscles. Within‐group effect sizes were large (d > 1·0) for both follow‐up periods in both muscles. The anova found a significant effect for time (F = 78·6; P < 0·001) for changes in pain intensity and active pain‐free mouth opening (F = 17·1; P < 0·001). Significant differences were found between pre‐intervention and both post‐intervention and follow‐up periods (P < 0·001) but not between the post‐intervention and follow‐up period (P > 0·7). Within‐group effect sizes were large (d > 0·8) for both post‐intervention and follow‐up periods. The application of treatment directed at the cervical spine may be beneficial in decreasing pain intensity, increasing PPTs over the masticatory muscles and an increasing pain‐free mouth opening in patients with myofascial TMD.     

Associations of pain intensity and pain‐related disability with psychological and socio‐demographic factors in patients with temporomandibular disorders: a cross‐sectional study at a specialised dental clinic

The study assessed whether psychological and socio‐demographic factors, including somatisation, depression, stress, anxiety, daytime sleepiness, optimism, gender and age, are associated with pain intensity and pain‐related disability in patients with temporomandibular disorders (TMDs). In total, 320 TMD patients were involved in the study. The psychological status of each patient was assessed with questionnaires, including the Symptom Checklist‐90 (SCL‐90), Epworth Sleeping Scale (ESS), stress questionnaire and Life Orientation Test‐Revised (LOT‐R). TMD pain, including pain intensity and pain‐related disability, was assessed with characteristic pain intensity (CPI) and disability points scales. The associations of psychological and socio‐demographic factors with pain intensity and pain‐related disability were assessed through logistic regression analyses. Higher pain intensity was significantly associated with more severe anxiety (P = 0·004), more severe somatisation (P < 0·001), more severe depression (P < 0·001), more severe stress (P = 0·001) and lower optimism (P = 0·025) in univariate regression analyses. However, multiple regression analysis showed that only somatisation was significantly associated with pain intensity (P < 0·001). Higher pain‐related disability was significantly associated with more severe anxiety (P < 0·001), more severe somatisation (P < 0·001), more severe depression (P < 0·001), more severe stress (P < 0·001) and lower optimism (P = 0·003) in univariate regression analyses. However, multiple regression analysis showed that only depression was significantly associated with pain‐related disability (P = 0·003). Among the psychological and socio‐demographic factors in this study, somatisation was the best predictor of pain intensity, while depression was the best predictor of pain‐related disability.     

A novel vibratory stimulation‐based occlusal splint for alleviation of TMD painful symptoms: a pilot study

This pilot study introduces a novel vibratory stimulation‐based occlusal splint (VibOS) for management of pain related to temporomandibular disorders (TMD). The study sample consisted of 10 patients (mean age: 40·5 ± 13·7 years, male/female: 3/7) who were using stabilisation splints for more than 2 months prior to the study onset and still complained of pain. Patients utilised the active and inactive VibOS during 15 days in a crossover designed clinical trial. The analysed variables were self‐reported VAS pain levels and number of painful sites to palpation (PSP). Statistical analysis was performed with repeated measures anova . At baseline, mean VAS pain levels for group I and II were 45·6 ± 21·0 mm and 37·4 ± 16·3 mm, respectively. Comparison between these baseline values showed no statistical difference (P > 0·05, unpaired t‐test). In group I, the inactive VibOS caused a slight increase in VAS pain levels, whereas the active VibOS promoted a significant decrease in VAS pain levels and PSP (P < 0·01). In group II, which received the active VibOS first, a significant decrease in VAS levels (P < 0·05) and in PSP (P < 0·01) was observed. No significant decrease in VAS pain levels or PSP (P > 0·05) was observed with the use of the inactive VibOS. In conclusion, this study demonstrated a good tendency of this novel VibOS in the alleviation of painful symptoms related to TMD after a 15‐day management period compared to control VibOS.     

The efficacy of non‐narcotic analgesics on post‐operative endodontic pain: A systematic review and meta‐analysis

The objective of this review was to evaluate the efficacy of non‐narcotic analgesics including non‐steroidal anti‐inflammatory drugs (NSAIDs) and/or paracetamol in the treatment of post‐operative endodontic pain. Additionally, we aimed to examine the possible association of study covariates on the pain scores using meta‐regression analysis. An electronic search was performed in 2016. After data extraction and quality assessment of the included studies (n = 27, representing 2188 patients), meta‐analysis was performed using a random‐effect inverse variance method. Meta‐regression analysis was conducted to examine the associations between effect sizes and study‐level covariates (P < 0·05). The results showed that administration of non‐narcotic analgesic was more effective than placebo in the management of post‐operative pain, resulting in a lower pain scores with a standardised mean difference of ?0·50 (95% CI= ?0·70, ?0·30), ?0·76 (95%CI= ?0·95, ?0·56), ?1·15 (95% CI= ?1·52, ?0·78), ?0·65 (95% CI= ?1·05, ?0·26) for immediately after the procedure, 6?, 12? and 24 h post?operative follow‐ups (test for statistical heterogeneity: P = 0·000, P = 0·000, P = 0·000 and P = 0·001), respectively. Our meta‐regression analysis provided the evidence for association between some study covariates with treatment effect, each at different follow‐ups. We concluded that the clinicians can manage post‐operative endodontic pain by administration of NSAIDs and/or paracetamol. However, analgesic regimens should be considered as important determinants when prescribing a pharmacological adjuvant.     

The impact of stress and anxiety on the pressure pain threshold of myofascial pain patients

Summary  The purpose of this study was to evaluate the influence of stress and anxiety on the pressure pain threshold (PPT) of masticatory muscles and on the subjective pain report. Forty-five women, students, with mean age of 19·75 years, were divided into two groups: group 1:29 presenting with masticatory myofascial pain (MFP), according to the Research Diagnostic Criteria for Temporomandibular Disorders and group 2: 16 asymptomatic controls. An electronic algometer registered the pain thresholds on four different occasions throughout the academic year. To measure levels of stress, anxiety and pain, the Beck Anxiety Inventory, Lipp Stress Symptoms Inventory and Visual Analog Scale (VAS) were used. Three-way anova and Tukey's tests were used to verify differences in PPT between groups, times and sites. Levels of anxiety and VAS were compared using Mann–Whitney test, while Friedman's test was used for the within-groups comparison at different times (T1 to T4). The chi-squared and Cochran tests were performed to compare groups for the proportion of subjects with stress (α = 0·05). Differences in PPT recordings between time ( P  = 0·001) and sites ( P  < 0·001) were detected. Higher levels of anxiety and lower PPT figures were detected at T2 (academic examination) ( P  = 0·001). There was no difference between groups for anxiety and stress at any time ( P  > 0·05). The MFP group also has shown significant increase of VAS at the time of academic examination ( P  < 0·001). External stressors such as academic examinations have a potential impact on masticatory muscle tenderness, regardless of the presence of a previous condition such as masticatory myofascial pain.     

Chlorhexidine gel and less difficult surgeries might reduce post‐operative pain,controlling for dry socket,infection and analgesic consumption: a split‐mouth controlled randomised clinical trial

Reports on post‐surgical pain are a few, controversial and flawed (by statistics and analgesic consumption). Besides, it is not known if chlorhexidine can reduce post‐extraction pain adjusting for its effect on prevention of infection and dry socket (DS). We assessed these. A total of 90 impacted mandibular third molars of 45 patients were extracted. Intra‐alveolar 0·2% chlorhexidine gel was applied in a split‐mouth randomised design to one‐half of the sockets. None of the included patients took antibiotics or analgesics afterwards. In the first and third post‐operative days, DS formation and pain levels were recorded. Predictive roles of the risk factors were analysed using fixed‐effects (classic) and multilevel (mixed‐model) multiple linear regressions (α = 0·05, β≤0·1). In the first day, pain levels were 5·56 ± 1·53 and 4·78 ± 1·43 (out of 10), respectively. These reduced to 3·22 ± 1·41 and 2·16 ± 1·40. Pain was more intense on the control sides [both P values = 0·000 (paired t‐test)]. Chlorhexidine had a significant pain‐alleviating effect (P = 0·0001), excluding its effect on DS and infection. More difficult surgeries (P = 0·0201) and dry sockets were more painful (P = 0·0000). Age had a marginally significant negative role (P = 0·0994). Gender and smoking had no significant impact [P ≥ 0·7 (regression)]. The pattern of pain reduction differed between dry sockets and healthy sockets [P = 0·0102 (anova )]. Chlorhexidine can reduce pain, regardless of its infection‐/DS‐preventive effects. Simpler surgeries and sockets not affected by alveolar osteitis are less painful. Smoking and gender less likely affect pain. The role of age was not conclusive and needs future studies.     

Effect of experimental jaw muscle pain on EMG activity and bite force distribution at different level of clenching

Bite force at different levels of clenching and the corresponding electromyographic (EMG) activity in jaw‐closing muscles were recorded in 16 healthy women before, during and after painful stimulation of the left masseter muscle. Experimental pain was induced by infusion of 5·8% hypertonic saline (HS), and 0·9% isotonic saline (IS) was infused as a control. EMG activity was recorded bilaterally from the masseter and temporalis muscles, and static bite force was assessed by pressure‐sensitive films (Dental Pre‐scale) at 5, 50 and 100% of maximal voluntary contraction (MVC) during each session. Visual feedback was applied by showing EMG activity to help the subject perform clenching at 5, 50 and 100% MVC, respectively. EMG activity at 100% MVC in left and right masseter decreased significantly during painful HS infusion (1·7–44·6%; P < 0·05). EMG activity at 5% and 50% MVC was decreased during HS infusion in the painful masseter muscle (4·8–18·6%; P < 0·05); however, EMG activity in the other muscles increased significantly (18·5–128·3%; P < 0·05). There was a significant increase in bite force in the molar regions at 50% MVC during HS infusion and in the post‐infusion condition (P < 0·05). However, there were no significant differences in the distribution of forces at 100% MVC. In conclusion, experimental pain in the masseter muscle has an inhibitory effect on jaw muscle activity at maximal voluntary contraction, and compensatory mechanisms may influence the recruitment pattern at submaximal efforts.     

Correlation between the levels of non‐specific physical symptoms and pressure pain thresholds measured by algometry in patients with temporomandibular disorders

Recent studies showed that patients with chronic TMD pain also feature increased sensitivity in other craniofacial regions, and even in remote peripheral areas, suggesting that nociceptive processing is centrally facilitated in this patient population. The aim of this study was to investigate the existence of a negative correlation between the levels of non‐specific physical symptoms and pressure pain thresholds measured by algometry at sites distant from the chief complaint of oro‐facial pain in patients with TMD. A total of 20 female patients were evaluated comprising 11 patients diagnosed with myofascial pain (Group I of RDC/TMD) and 9 patients with arthralgia (Group III of RDC/TMD), with both reporting chronic TMD pain for at least 3 months. Patients were tested by the pressure algometry technique, and, in the same visit, clinical diagnosis and levels of non‐specific physical symptoms, including pain‐related issues or not, were obtained. The raw scores were then standardised into a T‐score. The possible correlation between the dependent variable levels of non‐specific physical symptoms and pressure pain thresholds measured by algometry at sites distant from the chief complaint of oro‐facial pain was assessed with Spearman's correlation coefficient. Results were considered statistically significant, which stood a lower than 5% probability of occurring by chance (P < 0·05). A statistically significant (P = 0·02) negative correlation (?0·51) was found to exist between the levels of non‐specific physical symptoms, only if including issues involving pain‐related symptoms, and experimental pressure pain thresholds in patients with painful TMD.     

Effect of high‐frequency bio‐oxidative ozone therapy for masticatory muscle pain: a double‐blind randomised clinical trial

To evaluate the effect of bio‐oxidative ozone application at the points of greatest pain in patients with chronic masticatory muscle pain. A total number of 40 (40 women, with a mean age of 31·7) were selected after the diagnosis of myofacial pain dysfunction syndrome according to the Research Diagnostic Criteria for temporomandibular disorder (RDC/TMD). The patients were randomly divided into two groups: patients received the ozone therapy at the point of greatest pain, ozone group (OG; n = 20); patients received the sham ozone therapy at the point of greatest pain, placebo group (PG; n = 20). Ozone and placebo were applied three times per week, for a total of six sessions. Mandibular movements were examined, masticator muscles tenderness were assessed and pressure pain threshold (PPT) values were obtained. Subjective pain levels were evaluated using visual analogue sale (VAS). These assessments were performed at baseline, 1 month and 3 months. Ozono therapy decreased pain intensity and increased PPT values significantly from baseline to 1 month and 3 months in OG compared with PG. PPTs of the temporal (OG = 24·85 ± 6·65, PG = 20·65 ± 5·43, P = 0.035) and masseter (OG = 19·03 ± 6·42, PG = 14·23 ± 2·95, P = 0.007) muscles at 3 months of control (T2) were significantly higher in the OG group. PPT value of the lateral pole was also significantly higher at T2 in the OG group (OG = 21·25 ± 8·43, PG = 15·35 ± 4·18, P = 0.012). Mandibular movements did not show significant differences between treatment groups except right lateral excursion values at T2 (OG = 8·90 ± 1·77, PG = 6·85 ± 2·41, P = 0.003); however, OG demonstrated significantly better results over time. Overall improvements in VAS scores from baseline to 3 months were OG 67·7%; PG 48·4%. Although ozone therapy can be accepted as an alternative treatment modality in the management of masticatory muscle pain, sham ozone therapy (placebo) showed significant improvements in the tested parameters.     

Prevalence of temporomandibular disorder pain in Chinese adolescents compared to an age‐matched Swedish population

This study aimed to (i) assess the prevalence and perceived need for treatment of TMD pain, and its association with socio‐economic factors and gender, in adolescents in Xi?an, Shaanxi Province, China, and (ii) compare the prevalence and association with gender of TMD pain in Xi?an to an age‐matched Swedish population. We surveyed Chinese adolescents aged 15 to 19 years in Xi'an, China (n = 5524), using a questionnaire with two‐stage stratified sampling and the school as the sampling unit. The study included second‐year students at selected high schools. It also included an age‐matched Swedish population (n = 17 015) surveyed using the same diagnostic criteria for TMD pain as that used in the Chinese sample. The survey found TMD pain in 14·8% (n = 817) of the Chinese sample and 5·1% (n = 871) of the Swedish sample (P < 0·0001). Girls had significantly more TMD pain than boys in both the Chinese (P < 0·05) and Swedish (P < 0·001) samples. TMD pain increased with age in the Chinese population. Of the Chinese adolescents with TMD pain, 47% reported that they felt a need for treatment. Rural schools, low paternal education levels, poverty, living outside the home, poor general and oral health, and dissatisfaction with teeth all showed significant positive correlations with TMD pain. Prevalence of TMD pain in Chinese adolescents was significantly higher than in the Swedish sample.     

Associations among temporomandibular disorders,chronic neck pain and neck pain disability in computer office workers: a pilot study

Neck pain is the most common musculoskeletal complaint among computer office workers. There are several reports about the coexistence of neck pain and temporomandibular disorders (TMD). However, there are no studies investigating this association in the context of work involving computers. The purpose of this study was to verify the association between TMD and neck pain in computer office workers. Fifty‐two female computer workers who were divided into two groups: (i) those with self‐reported chronic neck pain and disability (WNP) (n = 26) and (ii) those without self‐reported neck pain (WONP) (n = 26), and a control group (CG) consisting of 26 women who did not work with computers participated in this study. Clinical assessments were performed to establish a diagnosis of TMD, and craniocervical mechanical pain was assessed using manual palpation and pressure pain threshold (PPT). The results of this study showed that the WNP group had a higher percentage of participants with TMD than the WONP group (42·30% vs. 23·07%, χ² = 5·70, P = 0·02). PPTs in all cervical sites were significantly lower in the groups WNP and WONP compared to the CG. Regression analysis revealed TMD, neck pain and work‐related factors to be good predictors of disability (R² = 0·93, P < 0·001). These results highlighted the importance of considering the work conditions of patients with TMD, as neck disability in computer workers is explained by the association among neck pain, TMD and unfavourable workplace conditions. Consequently, this study attempted to emphasise the importance of considering work activity for minimising neck pain‐related disability.     

Quantitative sensory tests before and 1½ years after orthognathic surgery: a cross‐sectional study

Summary Quality control is very important in relation to invasive and lengthy treatments, such as integrated orthodontic and surgical correction of dentofacial deformities. The aim of this cross‐sectional study was to compare self‐reported somatosensory disturbances and quantitative sensory testing (QST) findings between two groups of patients and a healthy control group (n = 24); one group (n = 21) scheduled for bimaxillary orthognathic surgery (BOS) (pre‐op) and one group (n = 24) examined 1½ years after BOS (post‐op). Self‐reported data on pain and somatosensory disturbances were collected, and QST was performed at six trigeminal and one extratrigeminal site. Sensitivity to brush stroke, tactile stimuli, pinprick, two‐point‐discrimination threshold (2P‐DT), pinch pain threshold (PiPT) and pressure pain threshold (PPT) was evaluated. Results were analysed with anova s, Spearman’s Correlation, and chi square tests. Eight per cent of post‐op patients reported intra‐oral, 46% extra‐oral, and 46% no somatosensory disturbances. Sensitivity to brush stroke, pinprick and 2P‐DT was significantly increased at all examination sites in the post‐op patients compared with healthy controls (P < 0·002). Tactile thresholds and PPT did not differ between groups (P > 0·071). Pinch pain threshold were decreased in pre‐op patients compared with controls (P < 0·040). Self‐reported somatosensory disturbances were not correlated with QST findings. In conclusion; 1½ years after BOS, a large proportion of patients reported somatosensory disturbances and was hypersensitive to mechanical stimuli when compared with pre‐op patients and healthy controls. Pre‐op patients showed minor somatosensory changes. In addition to patients serving as their own control in prospective studies, a healthy control group and extratrigeminal control sites should be included in future studies.     

Pulp blood flow and sensibility in patients with a history of dental trauma undergoing maxillary expansion:: A prospective study

ObjectivesTo assess changes in pulp blood flow (PBF) and pulp sensibility (PS) in teeth of patients with a history of dental trauma undergoing maxillary expansion.Materials and MethodsTwenty-five patients requiring rapid maxillary expansion (RME) had the pulp status of their maxillary anterior teeth assessed using laser Doppler flowmetry, electric pulp testing, and thermal testing (CO2 snow). Each patient was tested at T1 (prior to expansion), T2 (2 weeks after rapid expansion), and T3 (3 months after expansion). Relationships between PBF, time interval, and history of trauma were evaluated using linear mixed modelling.ResultsWithin the Trauma group, PBF was significantly lower (P ≤ .05) at T2 and T3 in comparison to T1 and significantly lower (P ≤ .05) at T2 in comparison to T3. In the Non-trauma group, PBF at T2 was significantly lower (P ≤ .05) than PBF at T1 and T3; however, no significant difference (P > .05) in PBF was observed when comparing PBF at T1 and T3. In both groups, PS was maintained in almost all teeth (>90%).ConclusionsRME in healthy teeth causes reduction of PBF before reestablishment of pretreatment values. RME in traumatized teeth causes reduction of PBF without PBF being reestablished to pretreatment levels. Teeth with a history of compromise may have reduced adaptive capacity under insults such as RME, which should be appreciated during the informed consent process.     

Subjective food intake ability related to oral health‐related quality of life and psychological health

Reduced food intake ability can restrict an individual's choice of foods and might have a significant impact on the individual's quality of life and mental health. The aim of this study was to evaluate the correlations between self‐reported masticatory ability and oral health‐related quality of life (OHRQOL) and psychological health. The study included 72 (26 men, 46 women) adults with a mean age of 26·4 ± 8·6 years. Each participant completed the key subjective food intake ability (KFIA) test for five key foods, the Korean version of the Oral Health Impact Profile‐14 (OHIP‐14K) and three questionnaires for measuring anxiety, depression and self‐esteem. The participants were distributed into two groups by sex (a mean age of 23·9 ± 5·2 for men and 27·9 ± 9·8 for women) and by the median KFIA score. There were no significant differences in any of the variables according to sex. Thirty‐two participants (12 men, 20 women) in the lower KFIA group had a higher total OHIP‐14K (P < 0·001) and depression level (P < 0·05) than the 40 participants (14 men, 26 women) in the higher KFIA group. As the KFIA decreased, OHRQOL worsened (P < 0·001) and depression increased (P < 0·05). Participants with lower KFIA scores were more than 4·3 times as likely as to have a poor OHRQOL than the reference group (odds ratio, 4·348; 95% confidence interval, 1·554–12·170, P < 0·01). Lower subjective food intake ability is associated with a poor oral health‐related quality of life and higher depression level.     

Sensory recovery of non‐innervated free flaps and nasolabial island flaps used for tongue reconstruction of oncological defects

The aims of this study were to assess sensory recovery and impact on life quality after tongue reconstruction of oncological defects using different flap types. Thirty‐two patients who underwent tongue reconstruction for oncological defects 9·3 months after surgery with non‐innervated radial forearm free flaps (RFFFs) (N = 16), non‐innervated anterolateral thigh free flaps (ALTFFs) (N = 8) and nasolabial island flaps (NLIFs) (N = 8), and 20 age‐ and gender‐matched healthy controls participated in the study. The modalities assessed were cold detection threshold, warm detection threshold (WDT), cold pain threshold, heat pain threshold (HPT), mechanical detection threshold (MDT), mechanical pain threshold (MPT) and the Chinese version of Oral Health Impact Profile‐49. ALTFFs was significantly more sensitive than RFFFs (P = 0·005) and NLIFs (P = 0·014) for WDT, and showed a better sensory recovery than RFFFs for HPT (P = 0·011). ALTFFs and NLIFs showed significantly better sensory recovery than RFFFs for MDT (P < 0·005). NLIFs showed the best sensory recovery for MPT, followed by ALTFFs and lastly RFFFs (P = 0·004). NLIFs also showed the least impact on quality of life measures related to psychological discomfort compared to RFFFs and ALTFFs (P < 0·019). All modalities of sensory recovery in RFFFs did not depend on gender and post‐operative radiotherapy (P > 0·05). Different flaps for tongue reconstruction of oncological defects appear to have different patterns of sensory recovery and impact on quality of life measures. A longer follow‐up period and larger number of participants will be needed in future studies.     

Comparison of the effects of RME and fan-type RME on nasal airway by using acoustic rhinometry

Objective:To evaluate and compare the nasal airway changes following rapid maxillary expansion (RME) and fan-type RME using acoustic rhinometry (AR).Materials and Methods:The study sample consisted of three groups. The RME group comprised 15 subjects with maxillary transverse discrepancies and posterior crossbites. The fan-type RME group comprised 15 subjects, who had an anteriorly constricted maxilla with a normal intermolar width. The third group included 15 patients who had an ideal occlusion and received no orthodontic treatment and served as the control group. AR was used to measure nasal volume and the minimal cross-sectional area (MCA) before expansion (T1), after expansion (T2), and 6 months after expansion (T3). Each AR recording was performed with and without the use of a decongestant. Two-way analysis of variance was used to determine differences among the groups and three-way analysis of variance was used for the differences between groups. If evidence of statistically significant differences was found, a Bonferroni test was used.Results:The results showed that nasal volume and MCA were significantly increased with RME and fan-type RME immediately after expansion (P < .05). At the end of retention, nasal volume and MCA values of RME showed significant differences with both expansion fan-type RME and control groups (P < .05).Conclusions:RME and fan-type RME had similar effects on the nasal airway immediately after expansion. The increase in nasal volume and MCA was more stable in the RME group than in the fan-type RME group at the end of the retention period.     

Relationship between voice function and skeletal effects of rapid maxillary expansion

Objective:To evaluate the effects of rapid maxillary expansion (RME) on the vocal quality, maxillary central incisors, midpalatal suture, and nasal cavity in patients with maxillary crossbite.Materials and Methods:Coronal CT scans of 30 subjects (14 boys, 16 girls; mean age, 12.01 ± 0.75) were taken before RME (T0), and at the end of the expansion phase (T1). Voice samples of all patients were recorded with a high-quality condenser microphone (RODE NT2-A) on a desktop computer at T0 and T1. Statistical analyses were performed using a paired-sample t-test. The degree of association between the changes in the voice parameters and nasal width was assessed with Pearson''s correlation.Results:RME treatment produced a significant increase in the transverse dimensions of the midpalatal suture and nasal cavity between T0 and T1 (P < .05). The maximum F0 and jitter (%) results were shown to decrease statistically significantly from T0 to T1 (P < .001 and P = .042, respectively). Between T0 and T1, shimmer (%) and shimmer (dB) exhibited statistically significant increases (P = .037 and P = .019, respectively).Conclusions:After RME therapy, voice quality differences were found to be associated with increases in nasal width.