Showing papers in "Journal of Oral Rehabilitation in 2013"

Bruxism defined and graded: an international consensus

Abstract: To date, there is no consensus about the definition and diagnostic grading of bruxism. A written consensus discussion was held among an international group of bruxism experts as to formulate a definition of bruxism and to suggest a grading system for its operationalisation. The expert group defined bruxism as a repetitive jaw-muscle activity characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible. Bruxism has two distinct circadian manifestations: it can occur during sleep (indicated as sleep bruxism) or during wakefulness (indicated as awake bruxism). For the operationalisation of this definition, the expert group proposes a diagnostic grading system of 'possible', 'probable' and 'definite' sleep or awake bruxism. The proposed definition and grading system are suggested for clinical and research purposes in all relevant dental and medical domains.

Prevalence of sleep bruxism in children: a systematic review of the literature.

Abstract: The aim of the present investigation was to perform a systematic review of the literature dealing with the issue of sleep bruxism prevalence in children at the general population level. Quality assessment of the reviewed papers was performed to identify flaws in the external and internal validity. Cut-off criteria for an acceptable external validity were established to select studies for the discussion of prevalence data. A total of 22 publications were included in the review, most of which had methodological problems limiting their external validity. Prevalence data extraction was performed only on eight papers that were consistent as for the sampling strategy and showed only minor external validity problems, but they had some common internal validity flaws related with the definition of sleep bruxism measures. All the selected papers based sleep bruxism diagnosis on proxy reports by the parents, and no epidemiological data were available from studies adopting other diagnostic strategies (e.g. polysomnography or electromyography). The reported prevalence was highly variable between the studies (3·5-40·6%), with a commonly described decrease with age and no gender differences. A very high variability in sleep bruxism prevalence in children was found, due to the different age groups under investigation and the different frequencies of self-reported sleep bruxism. This prevented from supporting any reliable estimates of the prevalence of sleep bruxism in children.

Correlation between self-reported and clinically based diagnoses of bruxism in temporomandibular disorders patients

Abstract: The present investigation was performed in a population of patients with temporomandibular disorders (TMD), and it was designed to assess the correlation between self-reported questionnaire-based bruxism diagnosis and a diagnosis based on history taking plus clinical examination. One-hundred-fifty-nine patients with TMD underwent an assessment including a questionnaire investigating five bruxism-related items (i.e. sleep grinding, sleep grinding referral by bed partner, sleep clenching, awake clenching, awake grinding) and an interview (i.e. oral history taking with specific focus on bruxism habits) plus a clinical examination to evaluate bruxism signs and symptoms. The correlation between findings of the questionnaire, viz., patients' report, and findings of the interview/oral history taking plus clinical examination, viz., clinicians' diagnosis, was assessed by means of φ coefficient. The highest correlations were achieved for the sleep grinding referral item (φ = 0·932) and for the awake clenching item (φ = 0·811), whilst lower correlation values were found for the other items (φ values ranging from 0·363 to 0·641). The percentage of disagreement between the two diagnostic approaches ranged between 1·8% and 18·2%. Within the limits of the present investigation, it can be suggested that a strong positive correlation between a self-reported and a clinically based approach to bruxism diagnosis can be achieved as for awake clenching, whilst lower levels of correlation were detected for sleep-time activities.

Disc displacement within the human temporomandibular joint: a systematic review of a ‘noisy annoyance’

Abstract: To describe the scientific literature about the diagnosis, prevalence, aetiology, natural course and possible treatment modalities of disc displacements within the temporomandibular (TM) joint. PubMed was searched for specific indexing terms. The search yielded 1211 papers. After screening according to title and abstract, 695 papers were excluded, and after full-text reading, 107 papers remained. Hand-searching of the reference lists resulted in an extra 47 papers. Thirteen studies, published since the literature search was carried out, were also included, resulting in 167 papers for this review. A disc displacement is a highly prevalent derangement within the TM joint, with reported prevalence ranging from 18% to 35% in the general population. A disc displacement with reduction is mostly a stable, pain-free and lifelong condition of the joint. In only a small minority of patients, the disc loses its capacity to reduce on opening. Surprisingly, only in rare cases, the loss of disc reduction is accompanied by signs and symptoms of a closed lock (viz. a painful and limited mouth opening). These signs and symptoms have a tendency to reduce and in many cases to resolve within months. The favourable natural course of disc displacements only warrants active treatment for symptomatic disc displacements without reduction. The primary treatment option is a conservative, non-surgical treatment focusing at speeding up the natural process of alleviation of pain and of improvement in mouth opening. For most patients, a disc displacement is just a pain-free, lifelong lasting, 'noisy annoyance' from their TM joint.

A cross-sectional study: non-carious cervical lesions, cervical dentine hypersensitivity and related risk factors.

Abstract: Summary The present survey aims to study the prevalence and clinical characteristics of non-carious cervical lesions (NCCLs) and cervical dentine hypersensitivity (CDH), as well as their possible risk factors in a general population in China. A total of 1023 subjects were included in the present study. Each subject completed a structured interview, and all teeth of each subject were examined by a practitioner to determine NCCLs and CDH. Teeth with NCCLs and CDH were diagnosed according to the tooth wear index and by a blast of air from a triple syringe, respectively. Binary logistic regression was completed by analysing the association of risk factors with the occurrence of NCCLs and CDH. Loss of attachment (LOA) and gingival recession (GR) of teeth with NCCLs and/or CDH were measured using Williams periodontal probe. The diagnoses of NCCLs and CDH established following a clinical assessment yielded an overall prevalence of 61·7% and 27·1%, respectively. The 60–69 age group had the greatest proportion of subjects with NCCLs or CDH. The pre-molars were the most commonly affected teeth type with NCCLs or CDH. The proportion of teeth with CDH associated with NCCLs increased significantly with age, but the proportion of teeth with CDH only associated with LOA or GR decreased slowly with age. The single variables and interactive effects of variables associated with the occurrence of NCCLs include the following: age group, occupation type, method of toothbrushing, frequency and method of toothbrushing, and method of toothbrushing and duration of a toothbrush used. Gender, age group, occupation type and frequency of toothbrushing were associated with the occurrence of CDH. The current study presented higher prevalence of NCCLs and CDH in a general Chinese population. Both diseases were closely associated with age and periodontal status. The portion of the population with NCCLs or CDH had different risk factors.

Periodontal diseases and stress: a brief review

Abstract: Periodontal diseases are common chronic inflammatory diseases caused by pathogenic microorganisms colonising the subgingival area and inducing local and systemic elevations of pro-inflammatory cytokines resulting in tissue destruction. Apparition and evolution of periodontal diseases are influenced by many local or systemic risk factors. Psychological stress has been suggested as one of them and may negatively influence the outcome of periodontal treatment. However, mechanisms explaining the possible relationship between stress and increased susceptibility to periodontal disease remain poorly understood. Several stress markers are found in blood and saliva of patients with periodontal diseases and influence the development of periodontal diseases by several mechanisms including modifications of the inflammatory response and changes in the composition of the dental biofilm. The aim of this review is to provide an insight into the relationship between psychological stress and periodontal diseases.

The relationship between resonance frequency analysis (RFA) and lateral displacement of dental implants: an in vitro study

Abstract: Summary This in vitro investigation was conducted to study the relationship between resonance frequency analysis (RFA) and lateral displacement measurements of dental implants. A total of 30 implant sites were prepared in nine fresh bovine bone specimens. The bone density around each preparation was determined by using cone beam computerized tomography (CBCT) and imaging software. Dental implants were then inserted during continuous registration of insertion torque. RFA measurements were performed in perpendicular and parallel to the long axis of the specimens. The bone blocks were embedded in plaster and fixated in a specially designed rig for displacement measurements. A lateral force of 25 N was applied via an abutment perpendicular and parallel to each implant and the displacement measured in μm. In addition, a flex constant (μm N−1) was calculated for each measurement. There was a significant inverse correlation between RFA and lateral implant displacement (μm) measurements and between RFA measurements and the flex constant in both perpendicular and parallel directions in bone (P ≤ 0·001). Moreover, both RFA and displacement measurements correlated with bone density (P ≤ 0·001). It is concluded that RFA measurements reflect the micromobility of dental implants, which in turn is determined by the bone density at the implant site.

Masticatory muscle sleep background electromyographic activity is elevated in myofascial temporomandibular disorder patients.

Abstract: Despite theoretical speculation and strong clinical belief, recent research using laboratory polysomnographic (PSG) recording has provided new evidence that frequency of sleep bruxism (SB) masseter muscle events, including grinding or clenching of the teeth during sleep, is not increased for women with chronic myofascial temporomandibular disorder (TMD). The current case-control study compares a large sample of women suffering from chronic myofascial TMD (n=124) with a demographically matched control group without TMD (n=46) on sleep background electromyography (EMG) during a laboratory PSG study. Background EMG activity was measured as EMG root mean square (RMS) from the right masseter muscle after lights out. Sleep background EMG activity was defined as EMG RMS remaining after activity attributable to SB, other orofacial activity, other oromotor activity and movement artifacts were removed. Results indicated that median background EMG during these non SB-event periods was significantly higher (p<.01) for women with myofascial TMD (median=3.31 μV and mean=4.98 μV) than for control women (median=2.83 μV and mean=3.88 μV) with median activity in 72% of cases exceeding control activity. Moreover, for TMD cases, background EMG was positively associated and SB event-related EMG was negatively associated with pain intensity ratings (0–10 numerical scale) on post sleep waking. These data provide the foundation for a new focus on small, but persistent, elevations in sleep EMG activity over the course of the night as a mechanism of pain induction or maintenance.

Oropharyngeal dysphagia in amyotrophic lateral sclerosis alters quality of life

Abstract: Summary Dysphagia is one of the most important complications encountered in amyotrophic lateral sclerosis (ALS). Our aim was to determine whether oropharyngeal dysphagia impacted the quality of life (QoL) of patients with ALS. Thirty consecutive patients were recruited (31–82 years, 18 men). Swallowing function was evaluated using a standardised videofluoroscopic barium swallow. All the patients completed a specific questionnaire on quality of life in dysphagia (SWAL-QoL) immediately after the videofluoroscopy. The results of dysphagia outcome severity scale separated 14 patients with oropharyngeal dysphagia and 16 with normal swallowing function. There was no difference in the average age, weight and body mass index of the two groups (dysphagic patients: 68 ± 11 kg versus non-dysphagic patients: 69 ± 14 kg). Most of the dysphagic patients had a bulbar affection based on their Norris scores which determine the importance of cranial nerves illness (20 ± 8), significantly lower than those of the non-dysphagic patients (35 ± 5) (P < 0·0001). There was no difference in the neurological peripheral symptoms evaluated by Amyotrophic Lateral Sclerosis Functional Rating Scale scores (dysphagic patients: 26 ± 7 versus non-dysphagic patients: 27 ± 8) (ns). The swallowing quality of life questionnaire revealed that the dysphagic patients had significant burden (P < 0·001). They were affected by the necessity to applied a food selection (P < 0·01), by the increase in eating duration (P < 0·05) and described a decrease in eating desire (P < 0·05). They complained of fear regarding the risk of dysphagia (P < 0·05). They also described difficulties with oral communication (P < 0·001). All of those complained about dysphagia which impacted directly mental health (P < 0·05) and social life (P < 0·05). In conclusion, oropharyngeal dysphagia is a common symptom accompanying ALS, which alters the patient's QoL, especially social health.

Transcutaneous neuromuscular electrical stimulation can improve swallowing function in patients with dysphagia caused by non-stroke diseases: a meta-analysis.

Abstract: Summary There is still debate over whether the effect of transcutaneous neuromuscular electrical stimulation (NMES) in dysphagia rehabilitation is superior to traditional therapy (TT). The purpose of this meta-analysis was to assess the overall efficacy by comparing the two treatment protocols. Published medical studies in the English language were obtained by comprehensive searches of the Medline, Cochrane and EMBASE databases from January 1966 to December 2011. Studies that compared the efficacy of treatment and clinical outcomes of NMES versus TT in dysphagia rehabilitation were assessed. Two reviewers independently performed data extraction. Data assessing swallowing function improvement were extracted as scores on the Swallowing Function Scale as the change from baseline (change scores). Seven studies were eligible for inclusion, including 291 patients, 175 of whom received NMES and 116 of whom received TT. Of the seven studies, there were two randomised controlled trials, one multicentre randomised controlled trial and four clinical controlled trials. The change scores on the Swallowing Function Scale of patients with dysphagia treated with NMES were significantly higher compared with patients treated with TT [standardised mean difference (SMD) = 0·77, 95% confidence interval (CI): 0·13 to 1·41, P = 0·02]. However, subgroup analysis according to aetiology showed that there were no differences between NMES and TT in dysphagia post-stroke (SMD = 0·78, 95% CI: −0·22 to 1·78, P = 0·13, 4 studies, 175 patients). No studies reported complications of NMES. NMES is more effective for treatment of adult dysphagia patients of variable aetiologies than TT. However, in patients with dysphagia post-stroke, the effectiveness was comparable.

Novel software for quantitative evaluation and graphical representation of masticatory efficiency.

Abstract: Blending of chewing gums of different colours is used in the clinical setting, as a simple and reliable means for the assessment of chewing efficiency. However, the available software is difficult to use in an everyday clinical setting, and there is no possibility of automated classification of the patient's chewing ability in a graph, to facilitate visualisation of the results and to evaluate potential chewing difficulties. The aims of this study were to test the validity of ViewGum - a novel image analysis software for the evaluation of boli derived from a two-colour mixing ability test - and to establish a baseline graph for the representation of the masticatory efficiency in a healthy population. Image analysis demonstrated significant hue variation decrease as the number of chewing cycles increased, indicating a higher degree of colour mixture. Standard deviation of hue (SDHue) was significantly different between all chewing cycles. Regression of the log-transformed values of the medians of SDHue on the number of chewing cycles showed a high statistically significant correlation (r² = 0.94, P < 0.01). ViewGum eliminates drawbacks of previous two-colour chewing gum test methods by the simplicity of its application. The newly developed ViewGum software provides speed, ease of use and immediate extraction of clinically useful conclusions to the already established method of chewing efficiency evaluation and is a valid adjunct for the evaluation of masticatory efficiency with two-colour chewing gum.

Is there relationship between temporomandibular disorders and head and cervical posture? A systematic review.

Abstract: The objective of this systematic review was to find sufficient evidence to deny or accept the association between the head and cervical posture and temporomandibular disorders (TMDs), and thus assist health professionals in the evaluation and treatment of patients with TMDs. A search was conducted through all publications written in English about this topic using the databases from Medline, ISI Web of Science, EMBASE, PubMed and Lilacs. The abstracts that fulfilled the initial guideline were retrieved and evaluated to ensure they met the inclusion criteria. To assess the methodological quality of the studies, we developed a questionnaire considering the following criteria: participant's eligibility, control group, diagnosis of TMDs, posture diagnosis and randomisation. Twenty-two studies were selected as potential studies based on their abstracts. Only seventeen studies actually fulfilled the inclusion criteria. The search provided information about the methodological quality of the studies, in which several methodological defects were found. The evidence presented in this systematic review shows that the relation between TMDs and the head and neck posture is still controversial and unclear. The insufficient number of articles considered of excellent methodological quality is a factor that hinders the acceptance or denial of this association.

Counselling and self-management therapies for temporomandibular disorders: a systematic review.

Abstract: The aim of this review was to investigate the effectiveness of counselling and other self-management-based therapies on muscle and temporomandibular joint (TMJ) pain relief and increasing the functional abilities of patients with temporomandibular disorders (TMD). A systematic literature review was conducted by three independent reviewers and included articles published up to 2012. PubMed and Cochrane Library electronic databases were used in addition to hand-searching to assess clinical outcomes for counselling and self-management approaches for TMD treatment. The review yielded 581 records that were narrowed down to 7. All included studies were classified as blind-randomized controlled clinical trials. The selected articles analysed revealed that counselling was able to improve tenderness upon masticatory muscle palpation and maximum mouth opening with and without pain in patients with TMD, with similar results to those of interocclusal appliances approaches. Thus, counselling- and self-management-based therapies could be considered a conservative low-cost and beneficial treatment alternative for treating TMD to potentially improve psychological domains and remove harmful behaviours for the control of the signs and symptoms of TMD.

Diagnosis and treatment of temporomandibular disorders: an ethical analysis of current practices

Abstract: The defining characteristic of a profession - and especially a health-care profession - is that the behaviour of its members is proscribed by a formal code of ethics. The main purpose of such codes is to guide practitioners' interactions with patients, assuring that patient interests are protected. In other words, the ethical code requires practitioners to place their patients' needs for proper diagnosis and appropriate treatment ahead of their own needs for income and advancement. The dental profession has a code of ethics that was developed by the American Dental Association many years ago; in most clinical situations, determination of proper behaviour is self-evident. However, the field of temporoman-dibular disorders (TMDs) has been the subject of considerable controversy for over half a century, and many people have argued that this makes it impossible to evaluate various approaches to treatment of TMDs within an ethical framework. In this article, the authors argue that the large volume of scientific evidence in the contemporary TMD literature provides an ethical framework for the diagnosis and treatment of patients with TMDs within a biopsychosocial medical model. They present a summary of the research with contemporary scientific integrity, which has produced that information over a period of many years. Based on that research, they conclude that dentists may provide conservative and reversible treatments that will be successful for most TMDs and in doing so will comply with the profession's code of ethics. Conversely, the authors claim that those dentists who continue to follow the older mechanistic models of TMD aetiology and treatment are not only out of step scientifically, but are placing their patients' welfare at risk by providing unnecessary irreversible bite-changing and jaw-repositioning interventions. Therefore, debate of these issues should not be solely focused on scientific merit, but also upon the compelling ethical obligations that dentists have as a result of the contemporary scientific literature regarding TMDs.

Direct composite restorations for the worn mandibular anterior dentition: a 7-year follow-up of a prospective randomised controlled split-mouth clinical trial.

Abstract: The purpose of this study was to report on the 7-year follow-up of 15 patients who took part in a prospective randomised controlled split-mouth trial to evaluate the performance and patient satisfaction of 107 direct composite restorations bonded to their worn anterior mandibular dentition. This is the continuation of a study by Poyser et al., which investigated the performance of the same direct composite restorations on this cohort of patients at 2.5 years. The results of the present study suggest that direct composite restorations bonded to the worn anterior mandibular dentition to have an approximate survival of 85% at the 7-year follow-up. Approximately 53% of patients experienced survival of all of their restorations. Pre-operative circumferential preparation did not influence restoration survival, patient satisfaction or other clinical variables (restoration staining, marginal discolouration, shade match, surface roughness and marginal adaptation). The time taken to initially build-up the restorations was shown to be statistically significant with a longer procedural time meaning less chance of the restoration being present at 7 years. This treatment modality exhibited no biological complications for the teeth, supporting periodontium or TMJ apparatus. The placement of these restorations provided an improvement in the aesthetics of the teeth, a reduction in the concern over the longevity of the worn lower anterior teeth, and improvements with regard to sensitivity experienced with hot or cold foods or drinks. Marginal breakdown was the most frequently recorded clinical complication. Thus, for the majority of patients, the restorations offered a high degree of patient satisfaction and required an acceptable level of maintenance in the 7-year follow-up period.

Natural course of temporomandibular disorders with low pain-related impairment: a 2-to-3-year follow-up study

Abstract: To describe the natural course of temporomandibular disorders (TMD) in patients with low levels of pain-related impairment, independently by the physical diagnoses they received. Amongst all patients who attended the TMD Clinic, University of Padova, Italy, during the year 2009, those who: (i) had Research Diagnostic Criteria for TMD (RDC/TMD) axis II Graded Chronic Pain Scale (GCPS) grade 0 or 1 scores, (ii) received counselling on their signs and symptoms at the time of their first visit and suggestions on how to self-manage their symptoms, (iii) did not attend the Clinic since the time of their last visit and (iv) were visited by the same resident, were recalled for a follow-up assessment during the period from September to December 2011. Sixty-nine patients (79% females; mean age 47.4 ± 11.3 years; range 26-77) of 86 who were potentially eligible accepted to enter the study. The time span since the first visit ranged from 23 to 36 months. At the follow-up assessment, the percentage of patients with muscle disorders decreased from 68.1% to 23.1%; disc displacement with reduction remained unchanged (52.1%), whilst the 5.7% of patients who had disc displacement without reduction with limited opening then showed absence of limitation; diagnoses related to other joint disorders decreased from 30.4% to 14.4% for arthralgia and from 27.5% to 24.6% for osteoarthritis/osteoarthrosis. In a sample of patients TMD with low pain-related impairment followed up with a single recall assessment at 2-to-3 years, the natural course of disease was generally favourable.

Practice-based clinical evaluation of metal-ceramic and zirconia molar crowns: 3-year results.

Abstract: Summary This practice-based study evaluates the clinical performance of conventionally luted metal–ceramic and zirconia molar crowns fabricated with pronounced anatomical core design and a prolonged cooling period of the veneering porcelain. Fifty-three patients were treated from 07/2008 until 07/2009 with either metal–ceramic crowns (MCC) (high-noble alloy + low-fusing porcelain) or zirconia crowns (Cercon System, DeguDent, Germany). Forty-nine patients (30 women/19 men) with 100 restorations (metal–ceramic: 48/zirconia: 52, mean observational period: 36·5 ± 6 months) participated in a clinical follow-up examination and were included in the study. Time-dependent survival (in situ criteria), success (event-free restorations) and chipping rates (defects of the veneering ceramics) were calculated according to the Kaplan–Meier method and analysed in relation to the crown fabrication technique, using a Cox regression model (P < 0·05). Three complete failures (metal–ceramic: 1, zirconia: 2) were recorded (survival rate after 3 years: metal–ceramic: 97·6%, zirconia: 95·2%). Of the metal–ceramic restorations, 90·9% remained event-free (two ceramic fractures, one endodontic treatment), whereas the success rate for the zirconia was 86·8% (two ceramic fractures, one endodontic treatment, one secondary caries). No significant differences in survival (P = 0·53), success (P = 0·49) and ceramic fracture rates (P = 0·57) were detected. The combination of a pronounced anatomical core design and a modified firing of the veneering porcelain for the fabrication of zirconia molar crowns resulted in a 3-year survival, success and chipping rate comparable to MCC.

A functional natural dentition for all--and for life? The oral healthcare system needs revision.

Abstract: The cost of dental care adds to the costs of the already overburdened health sector. Do we - as patients and as society -receive oral health care that is both aligned with the actual disease experience and also, critically based on up-to-date scientific knowledge about the major oral diseases? In many places, the practice of dentistry reflects a response to disease patterns that once existed and is based on diagnostic and therapeutic approaches that are no longer valid. Instead, a new cadre of dental professionals is needed, one that is capable of meeting the actual health needs of our populations. This cadre should ensure that patients maintain a functioning dentition from cradle to grave based on cost-effective disease control principles. There is an urgent need to: (i) reconsider the roles of the different oral health cadres involved in the provision of oral health care; (ii) integrate oral health into general healthcare services; and (iii) restructure the training of oral health personnel. We advocate a radical reform of the oral healthcare system involving the training of two new types of professionals integrated with the general healthcare system: The oral healthcare provider - a highly skilled professional specialised in the diagnosis and control of oral diseases and with a profound understanding of oral health as part of general health - and the oral clinical specialist - whose role is the provision of advanced oral rehabilitation, able also to treat people with complex chronic diseases and multiple medications.

Bite force measurements with hard and soft bite surfaces.

Abstract: Summary Bite force has been measured by different methods and over a wide variety of designs. In several instruments, the fact that bite surface has been manufactured with stiff materials might interfere in obtaining reliable data, by a more prompt activation of inhibitory reflex mechanisms. The purpose of this study was to compare the maximum voluntary bite force measured by a digital occlusal force gauge (GM10 Nagano Keiki, Japan) between different opponent teeth, employing semi-hard or soft bite surfaces. A sample of 34 young adults with complete natural dentition was studied. The original semi-hard bite surface was exchanged by a soft one, made of leather and rubber. Maximum voluntary bite force recordings were made for each tooth group and for both bite surfaces. Statistical analyses (Student's t-test) revealed significant differences, with higher scores while using the soft surface across sexes and tooth groups (P < 0·05). Differential activation of periodontal mechanoreceptors of a specific tooth group is mainly conditioned by the hardness of the bite surface; a soft surface induces greater activation of elevator musculature, while a hard one induces inhibition more promptly. Thus, soft bite surfaces are recommended for higher reliability in maximum voluntary bite force recordings.

A possible biomechanical role of occlusal cusp-fossa contact relationships

Abstract: Biomechanical features of occlusal contacts are important in understanding the role of the occlusion contributing to masticatory function Cusp-fossa contact is the typical pattern of occlusion between upper and lower teeth This includes static relations, such as that during clenching, and dynamic relations when mandibular teeth contact in function along the maxillary occlusal pathways, as during mastication During clenching in the maximum intercuspal position (ICP), cuspal inclines may take the role of distributing the occlusal forces in multi-directions thus preventing excessive point pressures on the individual tooth involved During chewing movement on the functional side, the mandible moves slightly from buccal through the maximum ICP to the contralateral side The part of the chewing cycle where occlusal contacts occur and the pathways taken by the mandible with teeth in occlusal contacts are determined by the morphology of the teeth The degree of contact is associated with the activity of the jaw muscles To obtain repeatable static and dynamic occlusal contact information provided by the morphology of the teeth, maximum voluntary clenching and chewing movements with maximum range are needed In conclusion, in addition to the standard occlusal concepts of centric relation/centric occlusion and group function/cuspid protection relation, biomechanics in static and dynamic cusp-fossa relationships should be included to develop an understanding of occlusal harmony which includes no interfering or deflective contacts in functional occlusal contact

Ricinus communis treatment of denture stomatitis in institutionalised elderly

Abstract: This study compared the effectiveness of Ricinus communis (RC) with Nystatin (NYS) and Miconazole (MIC) in the treatment of institutionalised elderly with denture stomatitis (DS). They (n = 30) were randomly distributed into three groups: MIC, NYS or RC. Clinical and mycological evaluations were performed prior to the use of the antifungal (baseline) and repeated after 15 and 30 days of treatment. The sample was clinically examined for oral mucosal conditions. Standard photographs were taken of the palate, and the oral candidiasis was classified (Newton's criteria). Mycological investigation was performed by swabbing the palatal mucosa, and Candida spp. were quantified by counting the number of colony-forming units (cfu mL⁻¹). The clinical and mycological data were analysed, respectively by Wilcoxon and Student's t-test (α = 0.05). Significant improvement in the clinical appearance of DS in the MIC and RC groups was observed between the 1st and 3rd collections (MIC - P = 0.018; RC - P = 0.011) as well as between the 2nd and 3rd collections (MIC - P = 0.018; RC - P = 0.011). Neither groups showed a statistically significant reduction in cfu mL⁻¹ at any time. Although none of the treatments decreased the cfu mL⁻¹, it was concluded that Ricinus communis can improve the clinical condition of denture stomatitis in institutionalised elderly patients, showing similar results to Miconazole.

In vitro chipping behaviour of all-ceramic crowns with a zirconia framework and feldspathic veneering: comparison of CAD/CAM-produced veneer with manually layered veneer.

Abstract: The purpose of this in vitro study was to assess the breaking load of zirconia-based crowns veneered with either CAD/CAM-produced or manually layered feldspathic ceramic. Thirty-two identical zirconia frameworks (Sirona inCoris ZI, mono L F1), 0·6 mm thick with an anatomically shaped occlusal area, were constructed (Sirona inLab 3.80). Sixteen of the crowns were then veneered by the use of CAD/CAM-fabricated feldspathic ceramic (CEREC Bloc, Sirona) and 16 by the use of hand-layered ceramic. The CAD/CAM-manufactured veneer was attached to the frameworks by the use of Panavia 2.0 (Kuraray). Half of the specimens were loaded until failure without artificial ageing; the other half of the specimens underwent thermal cycling and cyclic loading (1·2 million chewing cycles, force magnitude F(max) = 108 N) before the assessment of the ultimate load. To investigate the new technique further, finite element (FE) computations were conducted on the basis of the original geometry. Statistical assessment was made by the use of non-parametric tests. Initial breaking load was significantly higher in the hand-layered group than in the CAD/CAM group (mean: 1165·86 N versus 395·45 N). During chewing simulation, however, 87·5% (7/8) of the crowns in the hand-layered group failed, whereas no crown in the CAD/CAM group failed. The CAD/CAM-produced veneer was significantly less sensitive to ageing than the hand-layered veneer.

A randomised trial of a simplified method for complete denture fabrication: patient perception and quality

Abstract: Complete denture fabrication involves a series of complex technical procedures. Nevertheless, simplified methods may be as effective as conventional ones albeit the lesser use of time and resources, without disadvantage for the patient. This study compared a simplified method for complete denture fabrication to a conventional protocol in terms of oral health-related quality of life (OHRQoL), patient satisfaction and denture quality. Forty-two edentulous patients requesting treatment with complete dentures were randomly allocated into two study groups. Group S received dentures fabricated by a simplified method and Group C received conventionally fabricated dentures. Before interventions and after three and 6 months following insertion, OHRQoL and patient satisfaction were analysed by specific instruments. A prosthodontist assessed denture quality 3 months after delivery. Groups presented no difference for OHRQoL, denture quality and general satisfaction. Differences regarding patient satisfaction with some aspects of the dentures were found after 3 months (S > C), but were insignificant at 6 months. It was concluded that the simplified method is able to produce dentures of a quality comparable to those produced by the conventional method, influencing OHRQoL and patient satisfaction similarly.

Oral health-related quality of life in patients with tooth wear.

Abstract: The aim of this study was to investigate the impact of tooth wear (TW) on patients' oral health-related quality of life. A total of 198 participants were included in the study. They belonged to the following four different diagnostic categories: 51 patients with TW, 46 patients with painful temporomandibular disorders (TMD), 43 complete denture wearers and 58 healthy controls. The Dutch version of the Oral Health Impact Profile (OHIP-NL) was used to assess the patients' oral health-related quality of life. The results of the study show that patients with TW have an impaired oral health-related quality of life compared with healthy controls (P < 0·001). Furthermore, the impact of TW and of edentulousness do not differ significantly, while both of these oral conditions seem to have a lower impact on quality of life compared with painful TMD (P < 0·05). It was concluded that TW has a negative impact on patients' quality of life. This impact is comparable with that of edentulousness.

Long-term tooth loss in periodontally compromised but treated patients according to the type of prosthodontic treatment. A retrospective study.

Abstract: If prosthodontic treatment is considered after periodontal therapy, the questions arise i) does prosthodontic treatment affect the treatment outcome of the dentition in general and ii) which type of prosthesis is related to best treatment outcome of abutment teeth? Our goal was to compare long-term tooth loss after comprehensive periodontal therapy in patients with or without prosthodontic treatment. Ninety patients' charts with a total of 1937 teeth who had received comprehensive periodontal treatment 5-17 years ago by the same periodontist were retrospectively evaluated. Sixty-five patients received fixed dental prostheses (FDP; n = 29) and/or removable partial dentures anchored with clips (RPDC; n = 25) or double crowns (RPDD; n = 25). Twenty-five patients were also periodontally compromised but treated without prosthodontic treatment and served as a control group. A total of 317 teeth and 70 abutment teeth were lost during 9.7 ± 4.1 years of observation. Thereof, 273 teeth and 48 abutment teeth were lost due to periodontal reasons. Mean tooth loss amounted to 1.2 ± 1.5 (controls) and 4.4 ± 3.4 (partial dentures). Abutment tooth loss was 0.4 ± 1.1 (FDP), 1.0 ± 1.2 (RPDC) and 1.3 ± 1.0 (RPDD). Poisson regressions identified prosthodontic treatment, age, socio-economic status, diabetes mellitus, mean initial bone loss and aggressive periodontitis as factors significantly contributing to tooth loss. Age, diabetes and non-compliance contributed to abutment tooth loss. Not considering biomechanical factors, patients with prosthodontic reconstructions under long-term supportive periodontal therapy were at higher risk for further tooth loss than patients without prostheses. Not only the type of partial denture but also the patient-related risk factors were associated with abutment tooth loss.

Relationship between gagging severity and its management in dentistry.

Abstract: Summary The purpose of this study was to investigate how grading according to our new gagging reflex index correlated with patient background and subsequent management. After obtaining institutional approval and informed consent, 110 patients with a gagging problem were enrolled. The patients completed the State–Trait Anxiety Inventory (STAI), the Dental Anxiety Scale (DAS), and a health questionnaire at initial consultation. On the second visit, an intra-oral examination was carried out and the severity of gag reflex determined according to our new, 5-level Classification of Gagging Problem (CGP) index: normal gagging but not desensitised (G1 = score 1); mild gagging (G2 = score 2); moderate gagging (G3 = score 3); severe gagging (G4 = score 4); and very severe gagging (G5 = score 5). No difference was found in grade based on age or STAI or DAS scores. The CGP score in male patients was significantly higher than that in female. The management classification method and degree of desensitisation were investigated retrospectively in each patient at 3 months and 1 year after initial consultation. The higher the CGP grade, the more often intravenous sedation or general anaesthesia was required due to difficultly in desensitisation. The present results suggest that determining whether it is possible to examine the molar area without inducing the gag reflex offers the key to deciding the treatment strategy.

Association between perioral muscle pressure and masticatory performance.

Abstract: Summary The aim of this study was to determine the association between strength of the perioral muscles and masticatory performance. Subjects were 56 healthy adults (30 men and 26 women; mean age of 24·9 years) with normal occlusion. Perioral muscle pressure was measured using JMS tongue pressure measurement device, and maximum tongue pressure and cheek pressure on the habitual chewing side (H) and non-habitual side (non-H) were measured. The masticatory performance was evaluated using gummy jelly, and the amount of glucose extracted was measured after chewing under condition H or non-H. The association between sex and maximum tongue pressure was analysed using Student's t-test. Cheek pressure and the amount of the glucose extracted between condition H and non-H or between men and women were analysed by two-way repeated-measures anova. In addition, the correlations between maximum tongue pressure and cheek pressure on condition H, maximum tongue pressure and the amount of glucose extracted under condition H, and cheek pressure and the amount of glucose extracted under condition H were analysed using Pearson's correlation coefficients for men and women. The maximum tongue pressure, cheek pressure and the amount of glucose extracted were higher in men than in women. The amount of glucose extracted was higher under condition H than under condition non-H, but no significant difference in chewing side was observed in cheek pressure between men and women. Additionally, positive correlations were shown between maximum tongue pressure, habitual-side cheek pressure and the amount of glucose extracted on men and women. In conclusion, the association between higher perioral muscle pressure and better masticatory performance was shown.

Determination of daytime clenching events in subjects with and without self-reported clenching.

Abstract: To confirm the validity of self-awareness of daytime clenching, specific electromyogram (EMG) characteristics of clenching behaviour were determined using surface EMG recordings. Temporal muscle EMGs were recorded for 5 h in 13 subjects with self-reported clenching (clenching group: 27·5 ± 3·8 years old) and 12 subjects without self-reported clenching (control group: 28·6 ± 7·1 years old). All EMG data were recorded and stored on a portable EMG apparatus. The device was similar in size to a hearing aid, and suitable to record daytime EMG without restriction of daily activities. A clenching event was defined as muscle activity exceeding 10% of the maximum voluntary contraction. Furthermore, simultaneous voice recording was also performed to identify the corresponding EMG event as functional or parafunctional. The mean number of clenching events was 192·8 ± 228·8 and 24·8 ± 26·5 in the clenching and the control groups, respectively (P < 0·05, Mann-Whitney U-test); the number of functional events was not significantly different between the groups. Because there was a significant difference in the number of clenching events between the groups, self-reported daytime clenching is considered to be a reliable screening parameter for awake bruxism.

Repeatability and reliability of human eye in visual shade selection

Abstract: Summary Deficiencies in the human visual percep-tion system have challenged the efficiency of the visual shade-matching protocol. The aim of this study was to evaluate the repeatability and reliability of human eye in visual shade selection. Fifty-four volunteering dentists were asked to match the shade of an upper right central incisor tooth of a single subject. The Vita 3D-Master shade guide was used for the protocol. Before each shade-matching procedure, the definitive codes of the shade tabs were hidden by an opaque strip and the shade tabs were placed into the guide randomly. The procedure was repeated 1 month later to ensure that visual memory did not affect the results. The L*, a* and b* values of the shade tabs were measured with a dental spectrophotometer (Vita Easyshade) to produce quantitative values to evaluate the protocol. The paired samples t-test and Pearson correlation test were used to compare the 1st and 2nd selections. The Yates-corrected chi-square test was use to compare qualitative values. Statistical significance was accepted at P < 0·05. Comparing baseline and 1st month records, statistical significance (P < 0·001) was found among qualitative data regarding repeatability on a yes/no (1/0) basis, revealing a very low percentage of repeatability (11·1%). Comparing baseline and 1st month records, statistical significance was not found (P = 0·000) among the L*, a*, b* and ΔE variables. These results indicate that dentists perform insufficiently regarding repeatability in visual shade matching, but they are able to select clinically acceptable shades.

Cumulative survival rate and complication rates of single-tooth implant; focused on the coronal fracture of fixture in the internal connection implant.

Abstract: This retrospective study evaluated the 5-year cumulative survival rate and complication rates of a 4·0-mm internal connection implant (MicroThread™ Osseospeed™, Astra Tech) installed for single-tooth restoration. The patients who were treated at Asan Medical Center between 2006 and 2007 were included in this study. A life table analysis was used to calculate the 5-year cumulative survival rate. Comparisons of cumulative survival rates among implant position (anterior, premolar and molar), jawbone (maxilla, mandible), gender and prosthesis type (screw-retained, cement-retained) were performed using the log-rank test. Post-loading complications were analysed using Fisher's exact test. Twelve of 136 implants (anterior; 22, premolar; 25, molar; 89) were lost during the loading period, and 11 were removed due to coronal fracture of fixture. The 5-year cumulative survival rate of the whole arch was 91·9%, and that of the molar region was 87·6%. Statistically significant differences were observed in cumulative survival rates among implant position (P = 0·037), whereas no statistically significant differences were observed among gender, jawbone, prosthesis type. Forty-seven of 114 (41·2%) implants in the posterior region showed post-loading complications, including coronal fracture of fixture and abutment screw loosening.