Iven Klineberg

Fear of pain in orofacial pain patients

&NA; In the present study, we examined whether fear of pain, dental fear, general indices of psychological distress, and self‐reported stress levels differed between 40 orofacial pain patients and 40 gender and age matched control general dental patients. We also explored how fear of pain, as measured by the Fear of Pain Questionnaire‐III (J Behav Med 21 (1998) 389), relates to established measures of psychological problems in our sample of patients. Finally, we examined whether fear of pain uniquely and significantly predicts dental fear and psychological distress relative to other theoretically‐relevant psychological factors. Our results indicate that fear of severe pain and anxiety‐related distress, broadly defined, are particularly elevated in orofacial pain patients relative to matched controls. Additionally, fear of pain shares a significant relation with dental fear but not other general psychological symptomology, and uniquely and significantly predicts dental fear relative to other theoretically‐relevant variables. Taken together, these data, in conjunction with other recent studies, suggest greater attention be placed on understanding the fear of pain in orofacial pain patients and its relation to dental fear and anxiety.

Patient-related risk factors for implant therapy. A critique of pertinent literature

BACKGROUND Treatment planning for dental implants involves the assessment of patient-related risk factors prior to formulation of a treatment plan. The aim of this review was to assess relevant literature and provide evidence-based information on the successful surgical placement of dental implants. METHODS An electronic search of Medline, PubMed and the Cochrane Databases of Systematic Reviews was undertaken using a combination of MeSH terms and keywords. A handsearch was also performed and cross-referenced with articles cited in papers selected. The primary study parameter was implant failure. RESULTS Forty-three studies were selected based on specific inclusion criteria. Many studies contain confounding variables, numbers in subcategories are often too small for meaningful statistical analysis, and follow-up times vary and are often short-term. CONCLUSIONS There are many risk factors which the clinician is required to know and understand to advise patients, and consider in planning and treatment provision. Consistent evidence exists to show an increased failure rate with smokers, a history of radiotherapy and local bone quality and quantity. Weaker evidence exists to show a higher incidence of peri-implant disease in patients with a history of periodontitis-related tooth loss. Lack of evidence precludes definitive guidelines for patients with autoimmune disorders where expert opinion recommends caution. Osteoporotic patients show acceptable survival rates; however patients on oral bisphosphonates show a small incidence but high morbidity from osteonecrosis of the jaw. Emerging evidence suggests that there is a correlation between genetic traits and disruption of osseointegration.

Functional Heterogeneity in the Superior Head of the Human Lateral Pterygoid

The activity of the superior head of the human lateral pterygoid muscle (SHLP) is controversial. Given the non-parallel alignment of some SHLP fibers, the SHLP may be capable of differential activation. The aims were to clarify SHLP activity patterns in relation to location within SHLP. In 18 subjects, SHLP single motor units were intramuscularly recorded at computer-tomography-verified sites during horizontal (e.g., protrusion) and vertical (e.g., opening) jaw tasks (recorded by a jaw-tracking device) and at resting postural jaw position. None of 92 units was active at the resting postural position. Medially located units (21) showed activity during contralateral movement, protrusion, and opening; 5 were also active on jaw closing. There was a significant association between unit location and the number of units active during vertical tasks (i.e., jaw closing and clenching). Analysis of the data suggests differential activation within SHLP and raises the possibility of functional heterogeneity within SHLP.

The variability of condylar point pathways in open-close jaw movements

STATEMENT OF PROBLEM Clinical assessments of condylar movement often rely on the movement of a single clinically determined or average value condylar point. PURPOSE The aim of this investigation was to study the effect of differences in condylar point location on recorded movement trajectories with an open-close jaw movement. METHODS Recordings were made of the movements of various condylar points in 44 subjects. The points were identified clinically (average value points) and radiographically. RESULTS The trajectory of each condylar point, whether average value or radiographically determined, was different in form and dimension from any other condylar point within a subject for the same open-close jaw movement. CONCLUSIONS Depending on the point chosen in the vicinity of the condyle, quite different interpretations of condylar movement within a subject could be made. The data underscore the caution that must be exercised when interpreting condylar movement from the movement of a single condylar point.

Occlusion on implants – is there a problem?

Oral rehabilitation restores form and function and impacts on general health. Teeth provide a discriminating sense of touch and directional specificity for occlusal perception, management of food with mastication and swallowing, and awareness of its texture and hardness. Peripheral feedback for control of jaw muscles includes the enamel-dentine-pulp complex and mechanoreceptors in the periodontal tissues. The implications of feedback from periodontal and other intra-oral mechanoreceptors as well as changes in central representation are significant for function and adaptation to oral rehabilitation. With implants, in the absence of the periodontium and periodontal mechanoreceptor feedback, fine motor control of mastication is reduced, but patients are still able to function adequately. Further, there is no significant difference in function with full-arch fixed prostheses on teeth in comparison with implants. Predictable implant outcomes depend on bone support. Optimum restoration design appears to be significant for bone remodelling and bone strains around implants with occlusal loading. Finite element analysis data confirmed load concentrations at the coronal bone around the upper section of the implant where bone loss is commonly observed clinically. Load concentration increased with steeper cusp inclination and broader occlusal table and decreased with central fossa loading and narrower occlusal table size. It is recommended that occlusal design should follow a narrow occlusal table, with central fossa loading in intercuspal contact and low cusp inclination to minimise lateral loading in function and parafunction. Acknowledging these features should address potential problems associated with the occlusion in implant therapy.

Bilateral activation of the trigeminothalamic tract by acute orofacial cutaneous and muscle pain in humans

&NA; The conscious perception of somatosensory stimuli is thought to be located in the contralateral cerebral cortex. However, recent human brain imaging investigations in the spinal system report bilateral primary somatosensory cortex (SI) activations during unilateral noxious stimuli and that this ipsilateral spinal representation may be independent of transcallosal connections. In the trigeminal system, there is primate evidence for an ipsilateral somatosensory pathway through the thalamus to the face SI. However, the organization of the trigeminal nociceptive pathway in the human is not clear. The aim of this study was to determine whether noxious stimuli applied to the face are transmitted to the cerebral cortex by bilateral pathways. We used functional magnetic resonance imaging (fMRI) to compare ipsilateral and contralateral activation of the thalamus, SI and secondary somatosensory cortex (SII) during muscle and cutaneous orofacial pain and innocuous facial stimulation in healthy human subjects. We found that both muscle and cutaneous noxious stimuli, from injections of hypertonic saline into the right masseter or overlying skin, evoked bilateral increases in signal intensity in the region encompassing the ventral posterior thalamus as well as the face region of SI and SII. In contrast, innocuous unilateral brushing of the lower lip evoked a strict contralateral ventroposterior thalamic activation, but bilateral activation of SI and SII. These data indicate that, in contrast to innocuous inputs from the face, noxious information ascends bilaterally to the face SI through the ventroposterior thalamus in humans.

Differential activation of the human trigeminal nuclear complex by noxious and non-noxious orofacial stimulation

There is good evidence from animal studies for segregation in the processing of non‐nociceptive and nociceptive information within the trigeminal brainstem sensory nuclear complex. However, it remains unknown whether a similar segregation occurs in humans, and a recent tract tracing study suggests that this segregation may not exist. We used functional magnetic resonance imaging (fMRI) to define and compare activity patterns of the trigeminal brainstem nuclear complex during non‐noxious and noxious cutaneous and non‐noxious and noxious muscle orofacial stimulation in humans. We found that during cutaneous pain, signal intensity increased within the entire rostrocaudal extent of the spinal trigeminal nucleus (SpV), encompassing the ipsilateral oralis (SpVo), interpolaris (SpVi) and caudalis (SpVc) subdivisions. In contrast, muscle pain did not activate SpVi, but instead activated a discrete region of the ipsilateral SpVo and SpVc. Further, muscle noxious stimulation activated a region of the ipsilateral lateral pons in the region of the trigeminal principal sensory nucleus (Vp). Innocuous orofacial stimulation (lip brushing) also evoked a significant increase in signal intensity in the ipsilateral Vp; however, non‐noxious muscle stimulation showed no increase in signal in this area. The data reveal that orofacial cutaneous and muscle nociceptive information and innocuous cutaneous stimulation are differentially represented within the trigeminal nuclear complex. It is well established that cutaneous and muscle noxious stimuli evoke different perceptual, behavioural and cardiovascular changes. We speculate that the differential activation evoked by cutaneous and muscle noxious stimuli within the trigeminal sensory complex may contribute to the neural basis for these differences. Hum Brain Mapp, 2009.

Hematologic and Urinary Excretion Anomalies in Patients with Chronic Fatigue Syndrome

Patients with chronic fatigue syndrome (CFS) have a broad and variable spectrum of signs and symptoms with variable onsets. This report outlines the results of a single-blind, cross-sectional research project that extensively investigated a large cohort of 100 CFS patients and 82 nonfatigued control subjects with the aim of performing a case-control evaluation of alterations in standard blood parameters and urinary amino and organic acid excretion profiles. Blood biochemistry and full blood counts were unremarkable and fell within normal laboratory ranges. However, the case-control comparison of the blood cell data revealed that CFS patients had a significant decrease in red cell distribution width and increases in mean platelet volume, neutrophil counts, and the neutrophil-lymphocyte ratio. Evaluation of the urine excretion parameters also revealed a number of anomalies. The overnight urine output and rate of amino acid excretion were both reduced in the CFS group (P < 0.01). Significant decreases in the urinary excretion of asparagine (P < 0.0001), phenylalanine (P < 0.003), the branch chain amino acids (P < 0.005), and succinic acid (P < 0.0001), as well as increases in 3-methylhistidine (P < 0.05) and tyrosine (P < 0.05) were observed. It was concluded that the urinary excretion and blood parameters data supported the hypothesis that alterations in physiologic homeostasis exist in CFS patients.

Rehabilitation of children with ectodermal dysplasia. Part 2: an international consensus meeting.

A consensus meeting was arranged to provide an opportunity to discuss the residual nonconsensus questions following three rounds of a Delphi study. It was hoped that the nonagreements could be resolved to define a comprehensive protocol for the management of ectodermal dysplasia, particularly with respect to the use of dental implants in growing patients. An international panel of expert clinicians in pediatric dentistry, prosthodontics, and orthodontics was invited to be part of the Delphi study to develop agreement on clinical questions through a consensus of ideas. Each expert had been invited to form a study group or team within his or her home institution. As required by the Delphi protocol, a 90-part questionnaire was considered by the collaborating teams and progressed through three iterations with increasing agreement. This process is discussed in part 1 of the study. The residual nonconsensus questions, which represented 10% of the questionnaire, required collaborative interaction for resolution. The consensus meeting was held in London, England, over a 2-day period with support from Nobel Biocare and the British Dental Association.

Clinical and laboratory surface finishing procedures for zirconia on opposing human enamel wear: A laboratory study

AIM To investigate the effect of laboratory and clinical finishing procedures for zirconia on antagonistic enamel wear. MATERIALS AND METHODS Forty-eight yttria-tetragonal partially stabilised zirconia (Y-TZP) specimens were prepared and divided into four groups according to their surface preparation: laboratory polished (LP); laboratory polished and glazed (G); clinically adjusted (CA); and clinically adjusted and repolished (CAR). Enamel opposing enamel was used as a control. Pre-testing surface roughness for each group was determined using contact profilometry. Two-body wear resistance tests were conducted using a masticatory simulator. Enamel specimens were subjected to 120,000 cycles in distilled water (frequency 1.6 Hz, loading force of 49 N). Volumetric and vertical enamel losses were measured by superimposition of pre- and post-testing images using a three-dimensional laser scanner and software analysis. Scanning electron microscopy was used for qualitative surface analysis of pre- and post-testing zirconia and enamel surfaces. One-way ANOVA and multiple comparisons with Bonferroni corrections were used for statistical analysis at a significance level of α=0.05. RESULTS There was no statistical difference in volumetric and vertical enamel loss between CAR, G and LP. CAR produced statistically significantly less volumetric enamel loss compared with CA and control, and statistically significantly less vertical enamel loss compared with CA. Volumetric and vertical enamel loss were highly correlated in all groups. CONCLUSIONS Enamel wear by clinically ground zirconia is comparable to that of opposing enamel surfaces and greater than clinically repolished zirconia. Repolishing of zirconia restorations following clinical adjustment with diamond burs is effective in reducing antagonistic enamel wear.