Sareh Said Yekta

Assessment of trigeminal nerve functions by quantitative sensory testing in patients and healthy volunteers

PURPOSE Orofacial sensory dysfunction plays an important role in oral and maxillofacial surgery. Quantitative sensory testing (QST) is a psychophysical approach to evaluate thermal and mechanical somatosensation. PATIENTS AND METHODS The present human study 1) collected normative QST data in extraoral and intraoral regions, 2) analyzed effects of age, gender, and anatomical sites on QST, and 3) applied QST in 11 patients with iatrogenic inferior alveolar nerve lesions. Sixty (30 male and 30 female) healthy volunteers were tested bilaterally in the innervation areas of infraorbital, mental, and lingual nerves. Ten patients with sensory disturbances in innervation areas of the mental nerve were investigated at 1, 4, and 8 weeks after surgery. Another patient with a complete sensory loss after surgery was repetitively tested within 453 days after primary surgery (dental implant) and subsequent surgical reconstruction of the inferior alveolar nerve by autologous graft. RESULTS Older subjects were significantly less sensitive than younger subjects for thermal parameters. Thermal detection thresholds in infraorbital and mental regions showed higher sensitivity in women. Sensitivity to thermal stimulation was higher in the infraorbital region than in the mental and lingual regions. QST monitored somatosensory deficits and recovery of inferior alveolar nerve functions in all patients. CONCLUSIONS Age, gender, and anatomic region affect various QST parameters. QST might be useful in the diagnosis of inferior alveolar nerve disorders in patients. In dentistry, the monitoring of afferent nerve fiber functions by QST might support decisions on further interventions.

The impact of bisphosphonates on the osteoblast proliferation and Collagen gene expression in vitro

BackgroundBisphosphonates are widely used in the clinical treatment of bone diseases with increased bone resorption. In terms of side effects, they are known to be associated with osteonecrosis of the jaw (BONJ).The objective of this study was to evaluate the effect of bisphosphonates on osteoblast proliferation by cell count and gene expression analysis of cyclin D1 in vitro. Furthermore, the gene expression of the extracellular matrix protein collagen type I was evaluated. Nitrogen-containing and non-nitrogen-containing bisphosphonates have been compared on gene expression levels.MethodsHuman osteoblast obtained from hip bone were stimulated with zoledronate, ibandronate and clodronate at concentrations of 5 × 10-5M over the experimental periods of 1, 2, 5, 10 and 14 days. At each point in time, the cells were dissolved, the mRNA extracted, and the gene expression level of cyclin D1 and collagen type I were quantified by Real-Time RT-PCR. The gene expression was compared to an unstimulated osteoblast cell culture for control.ResultsThe proliferation appeared to have been influenced only to a small degree by bisphosphonates. Zolendronate led to a lower cyclin D1 gene expression after 10 days. The collagen gene expression was enhanced by nitrogen containing bisphosphonates, decreased however after day 10. The non-nitrogen-containing bisphosphonate clodronate, however, did not significantly influence cyclin D1 and collagen gene expression.ConclusionsThe above data suggest a limited influence of bisphosphonates on osteoblast proliferation, except for zoledronate. The extracellular matrix production seems to be initially advanced and inhibited after 10 days. Interestingly, clodronate has little influence on osteoblast proliferation and extracellular matrix production in terms of cyclin D1 and collagen gene expression.

Clinical Evaluation of a Biphasic Calcium Composite Grafting Material in the Treatment of Human Periodontal Intrabony Defects: A 12-Month Randomized Controlled Clinical Trial

BACKGROUND The aim of this study was to compare the clinical outcome of a novel biphasic calcium composite (BCC) biomaterial versus autogenous bone spongiosa (ABS) or open flap debridement (OFD) for the treatment of intrabony periodontal defects. METHODS Forty-five subjects with at least one intrabony defect with a probing depth (PD) >or=7 mm and a vertical radiographic bone loss >or=3 mm were enrolled in the study. Subjects were randomly assigned to treatment with BCC (n = 15), ABS (n = 15), or OFD (n = 15). Clinical parameters were recorded at baseline and 12 months after surgery and included the plaque index, gingival index, PD, clinical attachment level (CAL), and gingival recession. RESULTS In all treatment groups, significant PD reductions and CAL gains occurred during the study period (P <0.0001). At 12 months, patients treated with BCC exhibited a mean PD reduction of 3.6 +/- 0.7 mm and a mean CAL gain of 3.0 +/- 0.8 mm compared to baseline. Corresponding values for patients treated with ABS were 3.4 +/- 0.8 mm and 2.9 +/- 0.9 mm, whereas OFD sites produced values of 2.8 +/- 0.8 mm and 1.6 +/- 0.7 mm. Compared to OFD, the additional CAL gain was significantly greater in patients treated with BCC (P = 0.002) and ABS (P = 0.001). The additional PD reduction was significant for the BCC group (P = 0.011) and borderline significant for the ABS group (P = 0.059). There were no significant differences of PD and CAL changes between BCC and ABS groups. CONCLUSIONS The clinical benefits of BCC were equivalent to ABS and superior to OFD alone. BCC may be an appropriate alternative to conventional graft materials.

Failure to detect an association between aggressive periodontitis and the prevalence of herpesviruses.

BACKGROUND Herpes simplex virus type 1 (HSV-1), human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) have been suspected to play a causal role in periodontitis pathogenesis. The aim of this study was to determine the prevalence of these viruses in subgingival plaque samples of Caucasian patients with generalized aggressive periodontitis compared to periodontally healthy controls. METHODS A total of 65 patients with aggressive periodontitis and 65 unmatched controls from Germany were investigated in the study. Subgingival plaque samples were analysed for the presence of HSV-1, EBV and HCMV by quantitative real-time polymerase chain reaction assays. Viral antibody titres were determined quantitatively by immunosorbent assays. RESULTS DNA of HSV-1 and HCMV were detected in 1.5% of the patients and controls, whereas EBV DNA was present in 10.8% and 13.9% respectively. Detection rates of serum IgG against HSV-1 (76.1% versus 73.9%), EBV (98.5% versus 96.9%), HCMV (47.7% versus 46.2%) and IgM levels against HSV-1 (6.2% versus 1.5%), EBV (0% versus 0%), HCMV (0% versus 1.5%) did not significantly differ between patients and controls. CONCLUSION The data of our study do not suggest any contribution of HSV-1, EBV or HCMV to aggressive periodontitis in a German population. Ethnic and methodological aspects might have caused conflicting results of previous studies.

Impaired thermal perception in cluster headache

Cluster headache is characterized by attacks of severe periorbital pain. Repetitive burst activity in afferent fibers may induce plastic alterations in somatosensory synaptic processing as a prerequisite for recurring and chronic pain. This psychophysical study addressed hypothesized dysfunctions in craniofacial somatosensory processing in cluster headache disease. Thermal and mechanical sensory functions in the periorbital region were assessed by quantitative sensory testing (QST) in 25 cluster headache patients and 60 healthy volunteers. Perception of warmth (p<0.01), cold (p<0.000001), and pressure pain (p<0.05) was reduced on the cluster side as compared with the contralateral asymptomatic side. In contrast to healthy volunteers, warm detection threshold (WDT) and thermal sensory limen (TSL) on one side did not positively correlate with the other side. WDT and TSL negatively correlated with the elapsed time since last attack. All patients showed QST abnormalities on the headache side in comparison to healthy controls. Loss of sensory functions strongly preponderated gain. Several lines of evidence indicate a pivotal role of the hypothalamus in cluster headache pathophysiology. The impairment of warm and cold perception in patients may be based upon a dysfunction of the hypothalamus which is strongly involved in thermosensory control.

The influence of bisphosphonates on human osteoblast migration and integrin aVb3/tenascin C gene expression in vitro

BackgroundBisphosphonates are therapeutics of bone diseases, such as Pagets disease, multiple myeloma or osteoclastic metastases. As a severe side effect the bisphosphonate induced osteonecrosis of the jaw (BONJ) often requires surgical treatment and is accompanied with a disturbed wound healing.Therefore, the influence on adhesion and migration of human osteoblasts (hOB) after bisphosphonate therapy has been investigated by morphologic as well as gene expression methods.MethodsBy a scratch wound experiment, which measures the reduction of defined cell layer gap, the morphology and migration ability of hOB was evaluated. A test group of hOB, which was stimulated by zoledronate 5 × 10-5M, and a control group of unstimulated hOB were applied. Furthermore the gene expression of integrin aVb3 and tenascin C was quantified by Real-Time rtPCR at 5data points over an experimental period of 14 days. The bisphosphonates zoledronate, ibandronate and clodronate have been compared with an unstimulated hOB control.ResultsAfter initially identical migration and adhesion characteristics, zoledronate inhibited hOB migration after 50 h of stimulation. The integrinavb3 and tenascin C gene expression was effected by bisphosphonates in a cell line dependent manner with decreased, respectively inconsistent gene expression levels over time. The non-nitrogen containing bisphosphonates clodronate led to decreased gene expression levels.ConclusionBisphosphonates seem to inhibit hOB adhesion and migration. The integrin aVb3 and tenascin C gene expression seem to be dependent on the cell line. BONJ could be enhanced by an inhibition of osteoblast adhesion and migration. The gene expression results, however, suggest a cell line dependent effect of bisphosphonates, which could explain the interindividual differences of BONJ incidences.

Gender specific quality of life in patients with oral squamous cell carcinomas

BackgroundThe goal of this study was to evaluate the somatic and psychological effects by means of QUALITY OF LIFE (QOL) of surgical treatment of patients with oral squamous cell carcinoma. The factors gender, age, nicotine consumption, and tumour stage were taken into consideration.Methods54 patients after surgical resection of oral squamous cell carcinomas (OSCC) were analysed from 01.09.2005 to 31.05.2008. Inclusion criteria for the study were: age at least 18 years, no indication or treatment of synchronous and metachronous tumours.German translations of the EORTC H&N-35 and EORTC QLQ-C-30 questionnaires, as well as a general socioeconomic patient history were used as measuring instruments. The questionnaires were completed independently by the patients. The answers were translated into scale values for statistical evaluation using appropriate algorithms.ResultsAnalysis of the EORTC-QLQ-C-30 questionnaires demonstrated a tendency of more negative assessment of emotional function among the female participants, and a more negative evaluation of social function among the male participants. Greater tumour sizes showed significantly lower bodily function (p = 0.018). While a smaller tumour size was significantly associated with lower cognitive functioning (p = 0.031). Other cofactors such as age, nicotine consumption, and tumour stage only showed a tendency to influence the quality of sleep and daily life.ConclusionsThe data obtained within this investigation demonstrated that gender had the most significant power on the subjectively perceived postoperative quality of life. This factor is important e.g. in preoperative decision making regarding immediate microvascular reconstruction after e.g. mandibular resection and therefore QOL assessment should become integral component of the care of patients with OSCC.

Homotopic long-term depression of trigeminal pain and blink reflex within one side of the human face.

OBJECTIVE Electrical low-frequency stimulation (LFS) of cutaneous afferents elicits long-term depression (LTD) of craniofacial nociception and pain. The study addresses spatial organization of LTD within one side of the face. METHODS The blink reflex was evoked by electrical test stimulation in the supraorbital nerve area before and after conditioning LFS in 10 healthy volunteers. Noxious LFS (1Hz) was applied to skin afferents of supraorbital (sLFS), infraorbital (iLFS), or mental (mLFS) nerves. All stimuli were applied to the same side of the face with intensities of three times pain threshold. Volunteers rated the test stimulus intensity. Each volunteer participated in four sessions with sLFS, iLFS, mLFS, or without LFS (control). RESULTS Pain ratings of electrical test stimulation were differently affected in experimental sessions (p<0.01) with strongest reduction by -19.6% after sLFS. The reflex integral decreased by -34.7% significantly stronger after sLFS than in all other experimental conditions (p<0.001). Electrical pain thresholds increased significantly stronger in sLFS than in iLFS, mLFS, and control (p<0.001). CONCLUSIONS Trigeminal nociception and pain were inhibited by homotopic LFS at the forehead but not after heterotopic LFS of infraorbital and mental nerve skin afferents. SIGNIFICANCE Homotopic organization of ipsilateral trigeminal LTD in man may have implications for future neuromodulatory treatment of chronic craniofacial pain.

Cerebral activations resulting from virtual dental treatment

Pain, and anxiety of pain, for some people are serious problems in dental treatment. It is a common practical experience that even entering a dental surgery office, or the sound of a dental drill, may evoke vegetative correlates of toothache without any underlying disease. This everyday phenomenon suggests the hypothesis of a corresponding activation of pain-related brain areas by virtual dental treatment. Twenty healthy subjects viewed two different video clips presenting a dental treatment from the first-person perspective (simulation movie) and a moving hand holding an electrical toothbrush (control movie). Using functional magnetic resonance imaging, the cerebral hemodynamic responses that occurred during simulation and control movies were compared. Virtual dental treatment was associated with increased activity in pain-related brain areas such as the cingulate cortex, the insula, and primary and secondary somatosensory cortexes (SI, SII). The brain activation pattern indicates not only affective-motivational but also sensory-discriminative pain components during virtual dental treatment in all volunteers. Volunteers with a higher level of dental anxiety showed stronger activation of SI and SII. This may be a result of their higher anticipation of pain.

Impaired somatosensation in tongue mucosa of smokers

Smoking has been indicated as a risk factor for oral diseases and can lead to altered sense of taste. So far, the effects of sensory changes on the tongue are not investigated. In this study, quantitative sensory testing was used to evaluate somatosensory function in the lingual region. Eighty healthy volunteers were investigated (20 smokers, 20 non-smokers). Subjects were bilaterally tested in innervation areas of lingual nerves. Thresholds of cold and warm detection, cold and heat pain, and mechanical detection were determined. As control for systemic, extraoral effects of smoking, tests were additionally performed in 40 volunteers (20 smokers, 20 non-smokers) on the skin of the chin innervated by the mental branch of the trigeminal nerve. Cold (p < 0.001), warm detection thresholds (p < 0.001), and thermal sensory limen (p < 0.001) showed higher sensitivity in non-smokers as compared to smokers. Heat pain and mechanical detection, as well as all tests in the skin of the chin, showed no significant differences. The impaired temperature perception in smokers indicates a reduction of somatosensory functions in the tongue, possibly caused by nerve degeneration associated with smoking. Possible systemic effects of smoking do not seem to affect extraoral trigeminal branches.