Posterior scissors‐bite: masticatory jaw movement and muscle activity

Scissors‐bite is a malocclusion characterised by buccal inclination or buccoversion of the maxillary posterior tooth and/or linguoclination or linguoversion of the mandibular posterior tooth. This type of malocclusion causes reduced contact of the occlusal surfaces and can cause excessive vertical overlapping of the posterior teeth. This case–control study is the first to evaluate both masticatory jaw movement and masseter and temporalis muscle activity in patients with unilateral posterior scissors‐bite. Jaw movement variables and surface electromyography data were recorded in 30 adult patients with unilateral posterior scissors‐bite malocclusion and 18 subjects with normal occlusion in a case–control study. The chewing pattern on the scissors‐bite side significantly differed from that of the non‐scissors‐bite side in the patients and of the right side in the normal subjects. These differences included a narrower chewing pattern (closing angle, P < 0·01; cycle width, P < 0·01), a longer closing duration (P < 0·05), a slower closing velocity (P < 0·01) and lower activities of both the temporalis (P < 0·05) and the masseter (P < 0·05) muscles on the working side. In 96% of the patients with unilateral posterior scissors‐bite, the preferred chewing side was the non‐scissors‐bite side (P = 0·005). These findings suggest that scissors‐bite malocclusion is associated with the masticatory chewing pattern and muscle activity, involving the choice of the preferred chewing side in patients with unilateral posterior scissors‐bite.     

Prevalence of whiplash trauma in TMD patients: a systematic review

The purpose of this systematic review was to describe the prevalence of whiplash trauma in patients with temporomandibular disorders (TMDs) and to describe clinical signs and symptoms in comorbid TMD/whiplash compared with TMD localised to the facial region. A systematic literature search of the PubMed, Cochrane Library and Bandolier databases was carried out for articles published from 1 January 1966 to 31 December 2012. The systematic search identified 129 articles. After the initial screening of abstracts, 32 articles were reviewed in full text applying inclusion and exclusion criteria. Six studies on the prevalence of neck trauma in patients with TMD met the inclusion criteria and were included in the review. Two of the authors evaluated the methodological quality of the included studies. The reported prevalence of whiplash trauma ranged from 8·4% to 70% (median 35%) in TMD populations, compared with 1·7–13% in the non‐TMD control groups. Compared with patients with TMD localised to the facial region, TMD patients with a history of whiplash trauma reported more TMD symptoms, such as limited jaw opening and more TMD pain, and also more headaches and stress symptoms. In conclusion, the prevalence of whiplash trauma is higher in patients with TMD compared with non‐TMD controls. Furthermore, patients with comorbid TMD/whiplash present with more jaw pain and more severe jaw dysfunction compared with TMD patients without a history of head–neck trauma. These results suggest that whiplash trauma might be an initiating and/or aggravating factor as well as a comorbid condition for TMD.     

Sex‐related differences in symptoms of temporomandibular disorders and structural changes in the lateral pterygoid muscle after whiplash injury

Whiplash injury is an initiating or aggravating factor of temporomandibular disorder (TMD). Although there are sex‐related differences in the mechanism of pain perception and pain control, there is a lack of research on differences in TMD after whiplash injury. We aimed to evaluate sex‐related differences in the clinical symptoms and magnetic resonance imaging (MRI) findings of patients with TMD attributed to whiplash injury. This retrospective, cross‐sectional study included 100 patients (50 women; 50 men; mean age, 37.60 years) who visited our oro‐facial pain clinic with symptoms of TMD after whiplash injury. All patients underwent detailed evaluations for history of trauma, and their clinical and MRI findings were comprehensively assessed. Women with TMD after whiplash injury perceived more pain and presented more tenderness upon palpation than did men with TMD. In addition, women showed higher volume (58% vs 26%) and signal changes (54% vs 20%) in the lateral pterygoid muscle (LPM) and more anterior disc displacement without reduction (ADDWoR) (40% vs 20%) than did men. The presence of ADDWoR (odds ratio, 10.58; P = 0.007) and condylar degeneration (odds ratio, 9.30; P = 0.015) predicted LPM volume; stressful conditions (beta = 1.34; P = 0.011) correlated with increased visual analogue scale scores, and sleep problem was associated with an increased palpation index (PI) (beta = 0.42; P < 0.001) and neck PI (beta = 0.49; P < 0.001) scores only in women. Our results showed sex‐specific differences in pain intensity, distribution of clinical and abnormal MRI findings, and their relationships, and these differences should be considered when treating patients with TMD.     

The association between neck disability and jaw disability

Summary The association between cervical spine disorders (CSD) and temporomandibular disorders (TMD) has been extensively investigated. However, no studies investigating the relationship between the level of jaw disability and neck disability have been published. Therefore, the objective of this study was to determine whether there was a relationship between neck disability measured using the neck disability index (NDI) and jaw disability measured through the jaw function scale (JFS). A sample of 154 subjects who attended the TMD/Orofacial Pain clinic and students and staff at the University of Alberta participated in this study. All subjects were asked to complete the NDI, the JFS, the jaw disability checklist (JDC), and the level of chronic disability of TMD (chronic pain grade disability questionnaire used in the RDC/TMD). Spearman rho test was used to analyse the relationship between neck disability and jaw disability. Multiple regression analysis was used to determine the association between the level of chronic disability of TMD and neck disability. A strong relationship between neck disability and jaw disability was found (r = 0·82). A subject with a high level of TMD disability (grade IV) increased by about 19 points on the NDI when compared with a person without TMD disability. These results have implications for clinical practice. If patients with TMD have neck disability in addition to jaw disability, treatment needs to focus on both areas because the improvement of one could have an influence on the other.     

Jaw movements in patients with a history of pain: an exploratory study

The aims were to determine whether individuals with a past history of pain exhibit (i) altered jaw movement (e.g. reduced amplitude, increased jaw movement variability) in comparison with matched asymptomatic controls, and (ii) correlations between psychological measures (e.g. catastrophising) and altered jaw movement variables. Sixteen participants with a history of trigeminal neuropathic pain (TNP) and 15 age‐ and gender‐matched healthy controls had jaw movements recorded during open/close, free gum chewing and chewing at standardised rates. All completed the Pain Catastrophising Scale (PCS), the Pain Self‐Efficacy Questionnaire (PSEQ), and the Depression, Anxiety and Stress Scales (DASS). Velocity and amplitude for open/close and chewing, as well as variability, bias and mean square error for open/close jaw movements were compared between groups. Spearman's rank correlation coefficient was used to relate kinematic variables with psychological variables. Statistical significance: P < 0·05. There were no significant differences in mean jaw velocity and amplitude between the TNP and control groups during the open/close jaw movements or free or standardised chewing. In comparison with control, the TNP participants exhibited significantly greater variability, bias and/or mean square error during slow and/or fast opening, and significantly greater variance in velocity and/or amplitude during free and standardised chewing. There were significant negative correlations between PCS scores and velocity and/or amplitude of free and/or standardised chewing. This exploratory study suggests that individuals with a history of pain have altered patterns of jaw movements in comparison with asymptomatic control participants and that catastrophising may play a role in the manifestation of these altered jaw movements.     

Comparison of survival rate and crestal bone loss of narrow diameter dental implants versus regular dental implants: A systematic review and meta‐analysis

The aim of the present study was to establish survival rates, as well as crestal bone loss (CBL) of narrow diameter implants (NDI), compared to regular diameter implants (RDI). The current review followed the Enhancing the QUAlity and Transparency Of health Research guidelines and Preferred Reporting Items for Systematic Reviews and Meta‐Analyses statement. We searched main databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Oral Health Group Trials Register) for articles addressing the focused question up to and including May 2018. Meta‐analyses were conducted for CBL and survival rates. Qualitatively, three clinical studies showed comparable CBL and survival rates between NDI and RDI at follow up. Only one study showed increased CBL around NDI compared to RDI. The overall weighted mean difference (WMD) for CBL (WMD = .06, 95% confidence interval [CI] = ‐.38‐.51, P=.76) and risk difference for survival rate (risk difference = .88, 95% CI = .22‐3.50, P=.85) were not significant between the NDI and RDI groups at follow up. NDI and RDI showed comparable CBL and survival rates. However, the findings of the present study should be interpreted with caution due to significant heterogeneity and the low number of included studies. Further randomized, controlled trials should be performed in order to obtain strong conclusions.     

Effects of delayed‐onset muscle soreness on masticatory function

The aim was to clarify the effects of experimentally provoked delayed‐onset muscle soreness (DOMS) in the jaw‐closing muscles on subjective and objective measures of masticatory function. Twenty‐one dentate female subjects, without pain‐related signs and symptoms of temporomandibular disorders, participated. Delayed‐onset muscle soreness was provoked with eccentric and concentric contractions of the jaw‐closing muscles using a custom‐made apparatus. At baseline, and 24 h and 1 wk after the exercises, data were gathered on the subjective measures of muscle fatigue, muscle pain, and masticatory chewing ability using visual analogue scale (VAS) scores, on the maximum voluntary bite force (MVBF), and on the food Mixing Ability Index (MAI). After 24 h, muscle fatigue and muscle pain had increased and the MAI had decreased. All had returned to baseline levels after 1 wk. There were no significant changes found in the chewing ability VAS scores and in the MVBF over time. After correction for its baseline value, the MAI after 24 h was found to be significantly related to the muscle pain after 24 h. In conclusion, DOMS in the jaw‐closing muscles can cause a decrease in the objectively scored chewing ability, while the subjectively scored chewing ability remained the same.     

Correlation between the median particle size of chewed frankfurter sausage and almonds during masticatory performance test

The correlation between chewing and gastric function is best reflected when the same food type is used during both tests. We proposed frankfurter sausage as test food for masticatory performance as it can also be used in gastric emptying test. The suitability of frankfurter sausage to determine masticatory performance, however, has never been examined. To examine the correlations between the median particle size of frankfurter sausage and almonds (as standard test food) after different numbers of chewing cycles. Twenty‐seven subjects performed masticatory performance tests by chewing 2 types of test foods, that is, a piece of almond or 5‐g frankfurter sausage cubes placed in a sealed latex bag, for 5 and 15 chewing cycles. For each individual, right and left sides were tested separately. Chewed samples obtained from both sides were pooled. Median particle sizes were determined using a multiple sieving method. Spearman’s rank correlation was used to examine any correlation between median particle sizes of the 2 test foods after 5 and 15 cycles. Median particle sizes after 5 and 15 cycles were 2.04 ± 0.87 and 0.95 ± 0.58 mm for almonds and 4.16 ± 0.19 and 3.73 ± 0.25 mm for frankfurter sausage, respectively. Significant correlations were observed between the median particle size of chewed frankfurter sausage after 15 cycles and that of chewed almonds after 5 and 15 cycles (r = .76, P < .01 and r = .52, P = .01, respectively). Frankfurter sausage chewed for 15 cycles may be suitable for the determination of masticatory performance in conjunction with gastric emptying test.     

Jaw closing movement and sex differences in temporomandibular joint energy densities

Energy densities (ED, mJ/mm³) quantify mechanical work imposed on articular cartilages during function. This cross‐sectional study examined differences in temporomandibular joint (TMJ) ED during asymmetric versus symmetric jaw closing in healthy females versus males. ED component variables were tested for differences between and within sexes for two types of jaw closing. Seventeen female and 17 male subjects gave informed consent to participate. Diagnostic criteria for temporomandibular disorders and images (magnetic resonance (MR), computed tomography) were used to confirm healthy TMJ status. Numerical modelling predicted TMJ loads (F_normal) consequent to unilateral canine biting. Dynamic stereometry combined MR imaging and jaw‐tracking data to measure ED component variables during 10 trials of each type of jaw closing in each subject's TMJs. These data were then used to calculate TMJ ED during jaw closing asymmetrically and symmetrically. Paired and Student's t tests assessed ED between jaw closing movements and sexes, respectively. Multivariate data analyses assessed ED component variable differences between jaw closing movements and sexes (α = 0.05). Contralateral TMJ ED were 3.6‐fold and significantly larger (P < .0001) during asymmetric versus symmetric jaw closing, due to significantly larger (P ≤ .001) distances of TMJ stress‐field translation in asymmetric versus symmetric movement. During asymmetric jaw closing, contralateral TMJ ED were twofold and significantly larger (P = .036) in females versus males, due to 1.5‐fold and significantly smaller (P ≤ .010) TMJ disc cartilage volumes under stress fields in females versus males. These results suggest that in healthy individuals, asymmetric compared to symmetric jaw closure in females compared to males has higher TMJ mechanical fatigue liabilities.     

Effect of complete and partial removable dentures on chewing movements

Partial or complete edentulism impairs mastication. However, it is unclear how the chewing cycle is affected by prosthetics. We evaluated the chewing movements of patients fitted with complete (CD) or removable partial denture (RPD). A total of 29 subjects were kinesiographically evaluated during chewing of peanuts and Optocal portions in a random sequence. The subjects were divided into two groups according to prosthesis type. Group RPD was composed of 14 partially edentulous patients using a lower distal extension RPD (mean age 61 ± 8 years), and group CD contained 15 completely edentulous patients using CD (mean age 65·9 ± 7·9 years) in both jaws. Opening, closing, occlusal and masticatory cycle times, movement angle (opening and closing), maximum velocity (opening and closing), total area and chewing cycle amplitudes were evaluated. The results were subjected to anova and Tukey's HSD test at a significance level of 5%. The RPD group exhibited shorter opening and closing phases and masticatory cycle time (P < 0·05). Maximum velocities were also higher in the RPD group, irrespective of the test material (P < 0·05). The area and amplitude of the chewing envelope was smaller in the CD group (P < 0·0001). The test material did not influence chewing cycles in any of the parameters evaluated (P > 0·05). RPD wearers use a faster chewing sequence with greater vertical and lateral jaw excursions compared with CD wearers.     

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.     

Two‐colour chewing gum mixing ability: digitalisation and spatial heterogeneity analysis

Many techniques are available to assess masticatory performance, but not all are appropriate for every population. A proxy suitable for elderly persons suffering from dementia was lacking, and a two‐colour chewing gum mixing ability test was investigated for this purpose. A fully automated digital analysis algorithm was applied to a mixing ability test using two‐coloured gum samples in a stepwise increased number of chewing cycles protocol (Experiment 1: n = 14; seven men, 19–63 years), a test–retest assessment (Experiment 2: n = 10; four men, 20–49 years) and compared to an established wax cubes mixing ability test (Experiment 3: n = 13; 0 men, 21–31 years). Data were analysed with repeated measures anova (Experiment 1), the calculation of the intraclass correlation coefficient (ICC; Experiment 2) and Spearman's rho correlation coefficient (Experiment 3). The method was sensitive to increasing numbers of chewing cycles (F_5,65 = 57·270, P = 0·000) and reliable in the test–retest (ICC value of 0·714, P = 0·004). There was no significant correlation between the two‐coloured gum test and the wax cubes test. The two‐coloured gum mixing ability test was able to adequately assess masticatory function and is recommended for use in a population of elderly persons with dementia.     

Influence of surgical orthodontic treatment on masticatory function in skeletal Class III patients

Skeletal Class III patients exhibit malocclusion characterised by Angle Class III and anterior crossbite, and their occlusion shows total or partially lateral crossbite of the posterior teeth. Most patients exhibit lower bite force and muscle activity than non‐affected subjects. While orthognathic surgery may help improve masticatory function in these patients, its effects have not been fully elucidated. The aims of the study were to evaluate jaw movement and the electromyographic (EMG) activity of masticatory muscles before and after orthognathic treatment in skeletal Class III patients in comparison with control subjects with normal occlusion. Jaw movement variables and EMG data were recorded in 14 female patients with skeletal Class III malocclusion and 15 female controls with good occlusion. Significant changes in jaw movement, from a chopping to a grinding pattern, were observed after orthognathic treatment (closing angle P < 0·01; cycle width P < 0·01), rendering jaw movement in the patient group similar to that of the control group. However, the grinding pattern in the patient group was not as broad as that of controls. The activity indexes, indicating the relative contributions of the masseter and temporalis muscles (where a negative value corresponds to relatively more temporalis activity and vice versa) changed from negative to positive after treatment (P < 0·05), becoming similar to those of control subjects. Our findings suggest that orthognathic treatment in skeletal Class III patients improves the masticatory chewing pattern and muscle activity. However, the chewing pattern remains incomplete compared with controls.     

Reliability and validity of the Karaduman Chewing Performance Scale in paediatric neuromuscular diseases: A system for classification of chewing disorders

Chewing disorders can be seen in children with neuromuscular diseases (NMDs), which may cause swallowing difficulties such as choking, retching and food stuck feeling in the throat. Due to these effects, it is important to determine chewing disorders early with appropriate assessment methods to plan appropriate therapies in NMDs. The aim of this study was to investigate reliability and validity of the Karaduman Chewing Performance Scale (KCPS) in children with NMDs. Age, sex and diagnosis were recorded. Children were asked to chew a standardised biscuit while video‐recording. Two physical therapists scored each video according to the KCPS. The correlation between the KCPS scores of 2 therapists was analysed for interobserver reliability. One therapist rescored the recordings after an interval of 2 weeks for intra‐observer reliability. The Pediatric Version of the Eating Assessment Tool (PEDI‐EAT‐10) was used for criterion‐based validity. Sixty‐eight children with a mean age of 8.34 ± 3.73 (min = 2.5, max = 14.5) years were included, of which 94.1% were male. Karaduman Chewing Performance Scale scores were found to be level 0 in 20 cases, level 1 in 35 cases, level 2 in 12 cases and level 3 in 1 case. A positive, very strong correlation was detected between 2 therapists (r = .93, P < .001) and between 2 examinations of 1 therapist (r = .83, P < .001). A good correlation between the KCPS and PEDI‐EAT‐10 was detected (r = .62, P < .001). Chewing function, especially food processing phase, deteriorated in children with NMDs. The KCPS could be used as a reliable and valid instrument in determining chewing performance level for children with NMDs.     

Two repetitive bouts of intense eccentric‐concentric jaw exercises reduce experimental muscle pain in healthy subjects

High‐intensity eccentric‐concentric contractions of the jaw‐closing muscles induce muscle soreness, fatigue and functional impairment of the jaw, resembling the symptoms of myalgia, according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). However, it is claimed that repetition of similar exercises can minimise these detrimental effects. This study aimed to evaluate the response of jaw‐closing muscles following two series of intense eccentric‐concentric exercises of the masticatory muscles in healthy subjects. Twelve pain‐free participants underwent 2 sessions of intense eccentric‐concentric jaw exercises, with 1‐week interval in between. Each session of jaw exercises comprises 6 sets of 5‐minute‐long bouts of concentric‐eccentric contractions. Self‐reported muscle fatigue and pain, maximum mouth opening without pain (MMO), pain pressure thresholds (PPTs) of temporalis and masseter muscles and maximum voluntary bite force (MVBF) were recorded before, immediately after, 24 and 48 hours after each bout of exercises. ANOVA for repeated measurements was used to analyse the data. During session 2, muscle pain and fatigue were statistically significantly decreased (P < .05) as compared to session 1. Furthermore, statistically significant increases of MVBF (P < .005), MMO (P < .005) and PPTs (P < .005) were found at session 2 as compared to session 1. Within the limitations of the study, is can be concluded that the repetition of eccentric‐concentric jaw‐closing exercises results in signs of muscle training. Future studies can elucidate whether this motor training might be useful for the treatment of myalgia.     

Improvements in smoothness of chewing cycles in adults with mandibular prognathism after surgery: a longitudinal study

Although adults with mandibular prognathism are known to show impaired smoothness of masticatory jaw movements, it remains uncertain whether/how the surgical‐orthodontic treatment is effective to improve masticatory jaw movements. The aims of this study were (i) to verify whether the surgical‐orthodontic treatment of patients with mandibular prognathism improve smoothness of the chewing jaw movements post‐operatively and, if so, (ii) to examine whether the improved parameters show similar quantities as those of the control subjects. The chewing jaw movements for 13 patients with mandibular prognathism were recorded at pre‐ and post‐treatment stages. The patient group was divided into two groups: Class III_closed showed full occlusal contact at the habitual intercuspal position, whereas Class III_open showed inability of occlusal contact between the upper and lower anterior teeth. The control group (CG) consisted of 52 subjects having acceptably good occlusion. The normalised jerk cost (NJC), movement duration and peak velocity in jaw closing were compared. For both Class III_open and Class III_closed groups, statistical comparisons revealed that the NJC and movement duration were decreased after the treatment, whereas the peak velocity was increased (all P < 0·01). For the Class III_open, these quantities at the post‐treatment stage did not show any significant differences compared with those for the CG. It is concluded that the smoothness of chewing jaw movements for patient with mandibular prognathism were improved after treatment, and for the patients with anterior open bite at pre‐treatment, the post‐operatively achieved smoothness of jaw‐closing movements did not differ from those of the CG.     

Factors associated with pain induced by orthodontic separators

Pain resulting from the application of orthodontic forces varies markedly across individuals. The reasons of this variability are still largely unknown. To investigate factors that may be associated with orthodontic pain following the application of orthodontic separators. One hundred and seven participants were screened for pain response over 48 h following placement of orthodontic elastomeric separators. The highest (n = 10) and lowest (n = 10) pain responders were identified, and data collected on tooth pain sensitivity to electrical stimulation in conjunction with using the Pain Catastrophising Scale (PCS), Dental Anxiety Scale (DAS) and cold pressor test (CPT). There were statistically significant differences between high‐ and low‐pain responders in catastrophising score (P ≤ 0·023). For every PCS magnification score of 1 unit higher, the relative risk of being a high‐pain responder was 1·6 (P = 0·002); those scoring higher on helplessness had a lower risk of being so. DAS scores of high‐pain responders were twice as high as those of low‐pain responder (P = 0·043). During the first 2 min of CPT, the high‐pain responders experienced more pain than the low‐pain responders (P ≤ 0·029). Tooth pain thresholds did not differ between the two different pain responder groups. Pain catastrophising, dental anxiety and cold sensitivity appear to modify the pain experienced following placement of orthodontic separators. Further research is needed to determine the validity of screening questions to identify at‐risk patients prior to commencing orthodontic treatment.     

Efficacy of articaine vs lignocaine in maxillary and mandibular infiltration and block anesthesia in the dental treatments of adults: A systematic review and meta‐analysis

The aim of the present systematic review and meta‐analysis was to address the following Population, Intervention, Comparison, and Outcome question: Is the efficacy of articaine better than lignocaine in adults requiring dental treatment? Four percent articaine was compared with 2% lignocaine for maxillary and mandibular infiltrations and block anesthesia, and with the principal outcome measures of anesthetic success. Using RevMan software, the weighted anesthesia success rates and 95% confidence intervals (CIs) were estimated and compared using a random‐effects model. For combined studies, articaine was more likely to achieve successful anesthesia than lignocaine (N = 18, odds ratio [OR]: 1.92, 95% CI: 1.45‐2.56, P < 0.00001, I² = 32%). Maxillary and mandibular infiltration studies showed obvious superiority of articaine to lignocaine (N = 8, OR: 2.50, 95% CI: 1.51‐4.15, P = 0.0004, I² = 41%). Maxillary infiltration subgroup analysis showed no significant difference between articaine and lignocaine (N = 5, OR: 1.69, 95% CI: 0.88‐3.23, P = 0.11, I² = 19%). For combined mandibular anesthesia studies, articaine was superior to lignocaine (N = 14, OR: 1.99, 95% CI: 1.45‐2.72, P < 0.0001, I² = 32%), with further subgroup analysis showing significant differences in both mandibular block anesthesia (N = 11, OR: 1.55, 95% CI: 1.19‐2.03, P = 0.001), I² = 0%) and mandibular infiltration (N = 3, OR: 3.87, 95% CI: 2.62‐5.72, P < 0.00001, I² = 0%), indicating that articaine is more effective than lignocaine in providing anesthetic success in routine dental procedures.     

Improvement in patients with a TMD‐pain report. A 6‐month follow‐up study

Even though chronic TMD pain tends to persist in most patients, some chronic patients show improvement. It is largely unknown which factors contribute to the improvement of chronic pain. The aim of this study is to investigate which factors, from a biopsychosocial perspective, help to predict improvement in patients with a report of TMD pain. Methods: Subjects with a report of TMD pain were recruited in seven TMD clinics. They received a baseline questionnaire which included a wide range of possible predictors for improvement. After 6 months they received a follow‐up questionnaire which included a measure to determine which participants were ‘improved’ or ‘not improved’. To study which predictive variables were associated with improvement, multiple regression models were built. Results: From the 129 patients who responded to the baseline questionnaire, 100 patients also filled in the follow‐up questionnaire (85% women, mean age (years) ± s.d. = 46·0 ± 13·8). Fifty percentage of these subjects had improved at the 6‐month follow‐up. Pain duration was the strongest (negative) predictor for 6‐month improvement (P = 0·009). Also the number of care providers (P = 0·017) and the degree of hindrance on function (P = 0·045) helped to predict improvement. Conclusions: The duration of the TMD‐pain complaint, the number of care practitioners attended and the degree of hindrance on function (negatively) helped to predict 6‐month improvement. No evidence is found to support the role of psychological or social factors on the improvement in patients with a report of TMD pain.