Inequalities within dentistry are common and are reflected in wide differences in the levels of oral health and the standard of care available both within and between countries and communities. Furthermore there are patients, particularly those with special treatment needs, who do not have the same access to dental services as the general public. The dental school should aim to recruit students from varied backgrounds into all areas covered by the oral healthcare team and to train students to treat the full spectrum of patients including those with special needs. It is essential, however, that the dental student achieves a high standard of clinical competence and this cannot be gained by treating only those patients with low expectations for care. Balancing these aspects of clinical education is difficult. Research is an important stimulus to better teaching and better clinical care. It is recognized that dental school staff should be active in research, teaching, clinical work and frequently administration. Maintaining a balance between the commitments to clinical care, teaching and research while also taking account of underserved areas in each of these categories is a difficult challenge but one that has to be met to a high degree in a successful, modern dental school.

BACKGROUND:The aim of this study was to evaluate the gingival blood flow of smokers and non-smokers with periodontal disease before and after surgical periodontal treatment.METHODS:Nine smokers and six non-smokers with at least two periodontal lesions were included in the study. Laser Doppler flowmetry was used to measure blood flow in two gingival sites and two skin sites. Two intrabony defects were treated surgically at the same time; enamel matrix derivative was applied at random to one of the sites, whereas the other site received a placebo gel. We measured resting gingival blood flow (GBF) and responses to cold pressor test (CPT) and to smoking and made continuous measurements of blood pressure (BP). Resting GBF levels of 26 young healthy subjects were used as a reference value.RESULTS:Resting GBF was significantly lower for the periodontitis patients compared to the reference subjects, regardless of smoking habits. GBF and gingival vascular conductance (VC) decreased significantly pre- and postoperatively in response to smoking. CPT evoked significant decreases in VC in smokers and non-smokers. Skin blood flow decreased significantly in response to CPT, more so in the non-smokers. BP was significantly higher in the non-smokers.CONCLUSIONS:Resting GBF of periodontitis patients was not lower in smokers than in non-smokers, but it was significantly lower than in the younger reference subjects. In contrast to our earlier findings in healthy subjects, smoking one cigarette may cause a decrease in GBF and VC in periodontitis patients. These observations suggested the existence of a dysfunction in the gingival vasculature in smokers and non-smokers with periodontitis.

It has previously been claimed that nitrite protects against infections caused by Candida albicans. Nitrate and nitrite are natural constituents of saliva. The aim of the present study was to investigate if patients with oral candidosis have amounts of nitrate and nitrite in their saliva that differ from those of control persons. The study comprised 17 women and 7 men who were allotted to two experimental groups with yeast infection and two control groups with no clinical signs of candidosis. Within both the experimental and the control group one group consisted of dentates, and one group was made up of denture-wearers. In total there were four groups with six patients in each. All participants were examined for oral yeasts by cultivation on a selective medium (CHROMagar Candida) and Gram stain. The isolates were identified after automated reading of ID32C-inoculated test kits (bioMérieux). Four of the participants suffered or had previously suffered from oral cancer. In denture wearers there was no difference in the amount of nitrate and nitrite in patients with yeast infections compared to controls. However, in dentate patients there was a significantly higher amount of both nitrate and nitrite in the saliva compared with controls. Therefore, high levels of nitrate and nitrite may not consistently protect against infections with C. albicans.

BACKGROUND AND AIMCigarette smoking is currently considered as a risk factor for periodontal disease. Controversy exists as to whether the vasoconstrictive property of nicotine is one of the pathogenic mechanisms. To this end we tested the hypothesis that cigarette smoking is causing vasoconstriction in the healthy human gingiva.MATERIALS AND METHODSGingival blood flow was continuously measured with laser Doppler flowmetry in healthy (n=13) casual consumers of tobacco. Simultaneously, recordings were made of skin blood flow in the forehead and the thumb as well as heart rate (HR) and blood pressure (BP). In another session infraorbital nerve block anaesthesia (INB) with 1.0 ml of Carbocain without vasoconstrictive additives was used to identify nervously mediated vascular responses to cigarette smoking (n=8).RESULTSCigarette smoking induced a modest hyperaemic response in the gingiva that was lower than the relative increases in BP and HR, and the calculated gingival vascular conductance decreased. In the forehead, flow responses were similar to those in the gingiva, while in the thumb a powerful vasoconstriction was observed. During the later part of the 10-min recovery period, BP and HR tended to decrease while blood flow in the gingiva and forehead remained high. INB potentiated the hyperaemic response to cigarette smoking in gingiva.CONCLUSIONSThe present results help to shed some light on the understanding of the vasoactive mechanisms induced by cigarette smoking, and to support the hypothesis that cigarette smoking causes nervously mediated vasoconstriction in the healthy human gingiva. However, the degree of vasoconstriction was far less than in the thumb skin, and in our subjects was overcome by the evoked rise in arterial perfusion pressure. As a consequence, gingival blood flow increased during smoking. It is speculated that small repeated vasoconstrictive attacks due to cigarette smoking may in the long run contribute to gingival vascular dysfunction and periodontal disease.

Spectral analysis of jaw acceleration confirmed that the human mandible ‘trembles’ at a peak frequency around 6 Hz when held in its rest position and at other stationary jaw openings. The 6 Hz tremor increased during very slow movements of the mandible, but other lower‐frequency peaks became prominent during more rapid jaw movements. These lower‐frequency peaks are likely to be the result of asymmetries in the underlying, voluntarily produced, ‘saw‐tooth’ movements. In comparison, finger tremor at rest and during slow voluntary movements had a mean peak frequency of about 8 Hz: this frequency did not change during rhythmical finger flexion and extension movements, but the power of the tremor increased non‐linearly with the speed of the movement. The resting jaw tremor was weakly coherent with the activity of the masseter and digastric muscles at the tremor frequency in about half the subjects, but was more strongly coherent during voluntary movements in all subjects. The masseter activity was at least 150 deg out of phase with the digastric activity at the tremor frequency (and at all frequencies from 2.5–15 Hz). The alternating pattern of activity in antagonistic muscles at rest and during slow voluntary movements supports the idea that the masticatory system is subject to pulsatile control in a manner analogous to that seen in the finger.

BACKGROUND AND AIMTobacco users and especially cigarette smokers are at higher risk than non-smokers for periodontal disease. The pathogenic mechanism has been proposed to be the vasoconstrictive properties of nicotine, with reduced gingival blood flow (GBF) as a contributing factor in the development of periodontal disease. However, in a previous study in humans, we found GBF to increase in response to acute exposure to snuff. The present study was designed to investigate whether the tobacco-induced acute GBF increase is dependent on intact nervous conduction. We further investigated the effect of piroxicam (NSAID) and dexchlorpheniramin (DCPA) (antihistamine) on the snuff-induced responses in the gingiva, to see if chemical mediators of inflammation also influenced the response.MATERIAL AND METHODSLaser Doppler flowmetry (LDF) was used to measure gingival blood flow bilaterally in the buccal maxillary gingiva, in the forehead skin and in the thumb. Also arterial blood pressure (BP) and heart rate (HR) were monitored. Infraorbital nerve block anaesthesia (INB), superficial mucosal anaesthesia, 20 mg piroxicam or 2 mg DCPA were used in combination with snuff to study the vascular responses to 500 mg snuff (1% nicotine).RESULTSSnuff induced a rapid increase in GBF that was higher than the increase in BP, indicating an active vasodilatation. The snuff-induced vasodilatation was partly blocked by INB and more so by superficial mucosal anaesthesia. Piroxicam and DCPA exerted diverse effects on vascular homeostasis but had no effect on the snuff-induced vasodilatation in the gingiva.CONCLUSIONSThe results of this study confirm that snuff induces local gingival vasodilatation, and imply that this vasodilatation most likely is a summation of responses due to both autonomic and antidromic reflex mechanisms. We further discuss the possible involvement of the nervously mediated effects of tobacco and nicotine on vascular homeostasis and in tobacco-associated periodontitis.

Snuff-induced blood flow responses in the gingiva were evaluated in 22 healthy casual consumers of tobacco. Laser Doppler flowmetry (LDF) was used to measure blood flow simultaneously and continuously on two gingival sites (buccal aspect of the papillae between the upper lateral incisors and canines). In addition, measurements of skin blood flow in the forehead and palmar side of the left thumb were performed. Arterial blood pressure (BP) and heart rate (HR) were also recorded. Unilateral application of commercial snuff (500 mg, 1%) caused a marked and rapid increase in gingival blood flow (GBF) on the exposed side (p < 0.001). Blood flow increased also in the contralateral gingiva and forehead skin (p < 0.05). Skin blood flow in the thumb showed an insignificant decrease. BP and HR increased. Vascular conductance increased significantly in the snuff-exposed gingiva but not in the contralateral gingiva or the forehead. Vascular conductance was largely unaffected in the thumb. It is concluded that acute application of snuff, besides giving rise to typical changes in BP and HR, increases GBF in and around the exposed area, probably through activation of sensory nerves and the subsequent release of vasodilatory peptides from their peripheral endings. Blood flow in unexposed gingival and forehead skin may increase probably due to humoral or nervously mediated mechanisms. However, a passive pressure-induced hyperaemia in the unexposed gingiva and forehead skin can not be excluded.

. Previous studies have suggested that low level laser (LLL) treatment at specific wavelengths can enhance motor and sensory function in peripheral nerves after injury. The dental pulp is innervated by unmyelinated C fibres and small myelinated Aδ fibres derived from the trigeminal ganglion, both of which are known to contain calcitonin gene related peptide (CGRP).

Paraffin tablets are commonly used in clinical saliva tests whereas chewing-gum is recommended to increase salivation in xerostomic patients. The aim of this study was to compare the effect on salivation of these stimuli. Saliva stimulated by chewing-gum or paraffin tablets was sampled on separate occasions from eight healthy subjects (25-45 yr), Whole or parotid saliva were collected for 6 min (1 min + 5 min) and 21 min (1 min + 5 min x 4), respectively, pH of saliva was measured with and without the addition of HCl (titrated pH). Total parotid protein was measured using the mu BSA-assay. Initially, flow rates were significantly higher during the chewing of gum vs. paraffin tablets (whole saliva 5.18 vs. 2.99 ml/min, parotid saliva 0.83 vs. 0.42 ml/min). Conversely, during final chewing periods, parotid flow rates, pH, and titrated pH were significantly higher during paraffin chewing. When comparing the stimuli, parotid protein output was higher initially during gum chewing, but in the final period paraffin chewing elicited the higher output. It was concluded that the clinical test of paraffin chewing gives a good estimate of the expected whole saliva response to chewing-gum. Furthermore, extended chewing of paraffin tablets seemed to influence parameters of parotid saliva positively.

Growth associated protein 43 (GAP 43) is an acidic membrane-bound phosphoprotein produced at high levels in developing and regenerating neurons. It is a substrate for protein kinase C and suggested to be involved in calcium-regulated release of axonal vesicular-contained neurotransmitters. Expression of GAP 43 has been demonstrated in the uninjured cat dental pulp which receives its sensory nerve supply from the trigeminal ganglion. The aim of this study was a detailed mapping of the spatial and time-dependent expression of GAP 43 and co-expression of neuropeptide Y (NPY) in dental peripheral target tissues and trigeminal neurons subsequent to inferior alveolar nerve (IAN) axotomy in rats, as background for later low-level laser studies. Unilateral sectioning of IAN, resulting in an almost complete loss of sensory nerve fibers in the ipsilateral dental pulp of the first molar, was performed. The avidin biotin complex (ABC) method was used to evaluate peripheral changes in GAP 43 expression at 4, 7 and 10 days. Ganglionic changes in GAP 43 and co-localization of neuronal NPY expression was examined at 4, 10 and 21 days using either the ABC method or double immunofluorescence labelling techniques and confocal microscopy. Axotomy resulted in an early upregulation and change in the peripheral distribution of GAP 43 in nerve profiles already 4 days post IAN axotomy suggesting a Schwann cell origin. Ten days post axotomy a pronounced upregulation of GAP 43 immunoreactivity could be demonstrated in neurons located in the mandibular region of the trigeminal ganglion, compared to the contralateral uninjured side. The peripheral and ganglionic upregulation of GAP 43 continued to persist at 21 days. A concomitant time-delayed shift and co-expression of NPY was demonstrated throughout in the GAP 43-upregulated ganglion cells 10 days post axotomy. Furthermore, confocal microscopy indicated that the intraneuronal distribution of NPY and upregulated GAP 43 expression showed a similar conformity and distribution in both perinuclear regions and cell periphery.

The reflex responses evoked by slowly rising pressure ('push') stimuli to an upper lateral incisor tooth in human masseter muscle were studied. Factors such as the preload (the static force applied to the tooth by the stimulus probe before the start of the push stimulus) and the shape of the stimulus wave; affected the outcome of the reflex response. When the stimulating probe did not apply preload to the tooth before the push stimulus took place, the force profile exhibited a large fast component as the probe took up the 'slack' in the periodontium. The fast component in the force profile was found to be responsible for inducing the inhibitory reflex (sole inhibitory reflex). When preload was applied, the size of the fast component in the force profile was reduced and the change in force rate became slower and smoother. This slower stimulus profile induced the sole excitatory reflex significantly more often (58% vs 21%) and the sole inhibitory reflex significantly less often (15% vs 52%) than in the experiments that used no preload. The shape of the stimulus wave that drove the stimulus probe was also of importance. Provided that a 0.5-N preload was applied to the tooth, the smoothest stimulus wave induced the sole excitatory reflex most often. Fitting a rubber attachment to the tip of the probe made the push-force profile even smoother and thence more successful in inducing the sole excitatory reflex. Furthermore, the rubber tip reduced the possibility of the probe slipping off the tooth due to small and unavoidable movements of the participant's head. It is concluded that the periodontal mechanoreceptors can induce both excitatory and inhibitory reflexes on the jaw closers. The excitatory reflex becomes dominant when a smooth force is applied with preload. The inhibitory reflex becomes dominant when fast-force changes are applied on the tooth and/or no preload is used.

The incidence of inferior alveolar nerve (IAN) damage following removal of 3rd molar teeth or saggital split osteotomy has been reported as high as up to 5.5% and 100% respectively. Sensory aberrations in the IAN persisting for longer than 6 months leave some degree of permanent defect. Low level laser treatment (LLL) has a reported beneficial effect on regeneration of traumatically injured nerves. The purpose of this double blind clinical trial was to examine the effects of LLL using a GaAlAs laser (820 nm, Ronvig, Denmark) on touch and temperature sensory perception following a longstanding post surgical IAN injury. Thirteen patients were divided into two groups, one of which received real LLL (4 by 6 J per treatment along the distribution of the IAN to a total of 20 treatments during a time period between 36 - 69 days) and the other equivalent placebo LLL. The degree of mechanoreceptor injury as assessed by Semmes Weinstein Monofilaments (North Coast Medical, USA) were comparable in the two groups prior to treatment (p equals 0.9). Subsequent to LLL the real laser treatment group showed a significant improvement in mechanoreceptor sensory testing (p equals 0.01) as manifested by a decrease in load threshold (g) necessary to elicit a response from the most damaged area. The placebo LLL group showed no significant improvement, In addition, the real LLL group reported a subjective improvement in sensory function too. The degree of thermal sensitivity disability as assessed using a thermotester (Philips, Sweden) was comparable between the two groups prior to LLL p equals 0.5). However, there was no significant improvement in thermal sensitivity post LLL for either the real or placebo laser treated groups. In conclusion, GaAlAs LLL can improve mechanoreceptor perception in longstanding sensory aberration in the IAN.

Laser Doppler flowmetry was used in 14 subjects to investigate the effect of sodium lauryl sulfate (SLS) on gingival microcirculation. SLS, the most widely used detergent in toothpastes, exhibits a denaturing property, increases oral mucosal permeability and may cause epithelial desquamation of oral soft tissues. Gingival blood flow (GBF) was measured bilaterally 3 mm above the gingival margin, between the central and lateral maxillary incisors, before and after application of 1.5% SLS for 90 s to the gingiva on one side. The contralateral side served as a control with water application only. Relative changes in GBF were measured for 15 min on both sides. SLS increased the median GBF significantly between the 2nd and 10th min with a peak at 8 min, whereafter the flow decreased towards baseline. On the contralateral side, GBF initially declined before returning to baseline. 10 subjects felt a burning pain from the gingiva after SLS application and GBF increased in all of them. SLS increased the relative gingival blood flow presumably due to its penetrating and irritative properties, which resulted in vasodilatation. Laser Doppler flowmetry may be a useful non-invasive method for intraoral testing of different agents meant for oral use.

Das Ziel der hier vorgestellten Untersuchung war es, die Auswirkung von Intrusion sowie Extrusion auf die Blutversorgung der Pulpa am Menschen zu ermitteln. Die Unterschiede der Durchblutungsänderungen wurden an zehn lateralen Inzisiven (sechs Probanden) durch Laser Doppler Flowmetry (Perimed, Sweden) mittels an den bukkalen Flächen der Zähne befestigter Metallröhrchen gemessen. Die Brackets wurden an den Zähnen 13 und 23 befestigt, und intrusive bzw. extrusive Kräfte von 2 N wurden an den zu untersuchenden Zähnen über einen Zeitraum von fünf Minuten appliziert. Der jeweilige kontralaterale Zahn diente als Kontrolle. Die Extrusion bewirkte keine signifikante Veränderung des Pulpablutdurchflusses weder während noch nach der Aufhebung der extrusiven Kräfte. Intrusive Kräfte reduzierten jedoch während der ersten Minute der Kraftapplikation den Pulpablutdurchfluß um 20%. Während der nächsten vier Minuten kam es zu einer kontinuierlichen Zunahme des Pulpablutdurchflusses in Richtung des Ausgangswertes, und drei Minuten nach Aufhebung der Kraft erreichte er wieder den normalen Wert. Zusammenfassend kann festgestellt werden, daß die orthodontische Intrusion mit einer Kraft von 2 N eine temporäre Reaktion des Pulpablutdurchflusses hervorrief, die Extrusion hingegen keine Auswirkung auf den Pulpablutdurchfluß hatte.

Averaged reflex responses in the masseter muscle to transverse taps delivered to the upper central incisor were studied in 13 patients with chronic arthritic temporomandibular joint (TMJ) disease (arthritis group) and 28 patients having internal TMJ derangement (derangement group). The diagnostic assessment of TMJ disease was based on a combination of imaging methods. Fourteen symptomfree subjects served as a control for the electromyographic observations. The tapping force was increased in steps from 0.25 to 6 N. The pattern of the reflex response consisted of various inhibitory and excitatory waves, which were found to change with increasing tapping force. The first inhibitory wave (I-1) increased in duration with increasing tapping force in all subjects. At certain tapping forces, I-1 was of significantly lower amplitude and longer duration in the arthritis group than in the control group, but latency and threshold did not differ. The excitatory wave seemed to have longer latency and higher amplitude in the arthritis group than in the control subjects at some tapping forces. In summary we conclude that the pattern of the reflex response seemed to be similar in patients with different TMJ disorders and in symptomfree subjects. Only the level of inhibition, duration of I-1 and higher excitatory response, might separate the patients with arthritic TMJ disease and internal TMJ derangement from symptomfree subjects, but no specific differences between the groups could be found.