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Biomedical subjects

D van Steenberghe

Publications and source records attributed to D van Steenberghe.

At least 109 records · Page 6Linked to original sources
PubMed1994

The effect of electronic dental analgesia during sonic scaling.

The aim of the present study was to investigate the effects of electronic dental analgesia (EDA) during sonic scaling. The clinical trial included 30 healthy adult subjects and was conducted as a randomised single-blind split-mouth design. The applied procedure consisted of periodontal scaling by means of a sonic scaler, while using the EDA device either in an active or placebo state. Rather similar results were obtained for the subjective pain rating in both the active and the placebo trials. When patients rated their discomfort on a scale 0-4 from no pain to very severe pain, the mean (s.d.) score for both the EDA and the placebo was 1.2 (0.6). The subjective pain estimate was positively correlated to the electrical current intensity provided. This implied that with a stronger pain experience, patients tried to administer more anaesthesia by turning the dial of the control box to an increased intensity of the electrical current. This remained insufficient to eliminate pain sensation. It was concluded that application of electronic dental anaesthesia in periodontal treatment remains questionable.

Adult↗
PubMed1994

Role of periodontal ligament receptors in the tactile function of teeth: a review.

The tactile function of the human periodontal mechanoreceptors has mostly been studied by psychophysical approaches. It was concluded that periodontal mechanoreceptors play a major role in the tactile function of teeth. It must be noted however that the interocclusal tactile threshold is not solely determined by periodontal mechanoreceptors but also by pulpal, muscular or articular receptors. While temporomandibular joint receptors play a minor role, muscular receptors are important in the discriminatory ability for a mouth opening of 5 mm and more. To discriminate between the contribution of periodontal and other receptors in the oral tactile function, future studies should use appropriate psychophysical methodologies and well-defined stimulus parameters.

Dental Pulp↗
PubMed1994

The influence of surface-free energy on supra- and subgingival plaque microbiology. An in vivo study on implants.

The influence of surface free energy on supra- and subgingival plaque microbiology was examined in 9 patients with functional fixed prostheses supported by endosseous titanium implants. Two abutments (trans-mucosal part of the 2 stage implant) were replaced by either a new titanium abutment or a fluor-ethylene-propylene (FEP) coated abutment per subject. After 3 months of habitual oral hygiene, plaque samples were taken. Supragingival plaque was examined by means of differential phase-contrast microscopy, whereas for the subgingivial plaque additional analyses (DNA probes analysis, culturing) were performed. The subgingival samples were taken by paper-points and by scraping of the subgingival abutment surface. Differential phase-contrast microscopy showed a significant difference in plaque composition, especially when supragingival plaque was considered (P = 0.05). FEP coated abutments frequently harbored more coccoid microorganisms, whereas spirochetes or motile organisms were only detected around titanium abutments. Subgingivally, the number of colony forming units (CFU) in paper-points was comparable for both types of abutments. If the to-the-abutment-adhering plaque was considered, the number of CFU was 5 times higher on the titanium abutments than on the FEP coated abutments. However, this difference did not reach a statistical level of significance (P = 0.38). The DNA probe analysis of the subgingival plaque collected with paper-points showed a slightly higher frequency and concentration of perio-pathogens around the titanium abutments. However, the inter-substratum differences were smaller than the inter-subject differences. The latter seemed to be related to patient's dental status.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Adhesion↗
PubMed1994

Medium- and long-term effectiveness of a counterrotational electric toothbrush on plaque removal, gingival bleeding, and probing pocket depth.

This study analyzed the difference in effectiveness of a well-known manual toothbrush and a counterrotational electric toothbrush over medium- and long-term periods. Six dental students and six patients with moderate periodontitis participated in a split-mouth, single-blind experiment with repeated recordings of pocket depths and plaque and gingivitis indices. During the experiment, the use of interdental aids or mouth rinses was forbidden. At all intervals up to week 34, manual brushing resulted in significantly less plaque removal, especially at approximal sites. Use of the counterrotational electric toothbrush resulted in a significantly greater reduction in gingival inflammation and significantly increased pocket reduction, especially in the periodontitis group. A crossover experiment confirmed the inferiority of the manual cleaning. The long-term observations showed a slight decrease in efficiency of both brushes, thereby justifying the need for regular motivation reinforcement. The results of the current study demonstrate the long-term superiority of a counterrotational electric toothbrush over the manual toothbrush.

Adult↗
PubMed1994

Effect of a lactoperoxidase containing toothpaste in radiation-induced xerostomia.

Fractioned irradiation of the oral region may cause xerostomia and an increased infection risk. The aim of this study was to evaluate, in a single blind, cross-over trial, the effectiveness of a test toothpaste containing the lactoperoxidase system, compared to a normal fluoridated toothpaste. Twelve patients with pronounced xerostomia were examined during a 52-day period. The following parameters were observed: plaque and gingivitis index, bleeding on probing, probing pocket depth, attachment level, and quality of subgingival plaque (phase contrast microscopy). The test toothpaste reduced the rate of supragingival plaque formation over a longer period. Furthermore, gingival inflammation was lower in the test group. For the other parameters, time-dependent changes were not significant. This pilot-study demonstrates the efficacy of the lactoperoxidase system administered by a toothpaste, on supragingival plaque control in xerostomic patients.

Adult↗
PubMed1993

Maxillary bone resorption in patients with mandibular implant-supported overdentures or fixed prostheses.

For several years, implant-supported overdentures have been used with excellent results in rehabilitation of the edentulous mandible. The effect on the antagonistic jaw bone resorption however, has not yet been evaluated. The aim of this study was to examine on orthopantomograms the anterior and posterior maxillary ridge resorption in three groups of patients with different mandibular prosthetic reconstructions: (1) overdentures supported by two implants, (2) fixed prostheses supported by four to six implants, and (3) complete dentures. The results indicated a more pronounced annual bone resorption in complete denture wearers compared to patients with implant-supported overdentures. A limited but continuing bone resorption was observed for the patients with implant-supported overdentures, and a slightly higher annual bone resorption occurred in the implant-supported fixed prosthesis group.

Adult↗
PubMed1993

Masseter muscle fatigue during sustained clenching in subjects with complete dentures, implant-supported prostheses, and natural teeth.

A sustained submaximal (50%) clenching effort was performed in four patient groups to establish whether implant-supported prosthetic reconstructions influence myoelectrical signal parameters. The first group consisted of patients with natural teeth in both jaws. The other three groups consisted of patients who were edentulous in both jaws: one group had complete dentures; one had an overdenture in the mandible on two implants connected by a bar; and the third had an implant-supported fixed prosthesis in either the maxilla or the mandible. Surface electromyography indicated an increased myoelectrical output level that paralleled a higher bite force level for implant-supported reconstructions compared with complete dentures. Power spectrum analysis revealed a downward shift of the mean power frequency during sustained clenching in all groups except the implant-supported fixed prosthesis. The absence of a spectral shift in the latter group probably reflected a fear of biting too hard and fracturing the prosthesis.

Adult↗
PubMed1993

Bacterial colonization of the internal part of two-stage implants. An in vivo study.

This study aimed to investigate the presence of microorganisms in the inner thread of the fixture (endosteal implant part) of the Brånemark system. In 9 volunteers the apical part of 2 abutment screws that had been in place for 3 months was examined by means of differential phase-contrast microscopy. All screws harboured a significant quantity of microorganisms, mainly coccoid cells (86.2%) and nonmotile rods (12.3%). Motile organisms (1.3%) or spirochetes (0.1%) were only sporadically registered. A microbial leakage at the abutment/fixture interface probably is the most probable origin for this contamination.

Bacteria↗
PubMed1993

Role of periodontal mechanoreceptors in evoking reflexes in the jaw-closing muscles of the cat.

1. In anaesthetized cats the left maxillary and mandibular canine and incisor teeth were extracted. Nine weeks later the animals were anaesthetized again and titanium implants were placed into the edentulous ridge of the maxilla and mandible. 2. Terminal experiments were performed between 9 weeks and 10 months after inserting the implants. Recordings were made from the trigeminal ganglia and peripheral nerves of anaesthetized cats. Neurones were identified which responded to forces applied to the maxillary teeth but none was found which responded to forces applied to the implant. 3. The responses of motor units in the temporalis muscle were studied in response to ramp-plateau forces applied to the maxillary canine tooth and maxillary implant using peristimulus time histograms and cumulative sum (cusum) analysis. A small amount of inhibition of the motor units was observed in response to the applied forces to the implant. However, the inhibition was much more profound when similar forces were applied to the tooth. 4. The results confirm that when forces are applied to a tooth, periodontal mechanoreceptors are stimulated which evoke reflex inhibitions to motor units in the jaw-closing muscles. However, there is evidence that mechanoreceptors situated distant to the periodontium can also evoke such reflexes. 5. The results are discussed in relation to the overall functional role of periodontal mechanoreceptors in the reflexes of mastication.

Animals↗
PubMed1993

An in vivo study of the influence of the surface roughness of implants on the microbiology of supra- and subgingival plaque.

In nine patients with fixed prostheses supported by endosseous titanium implants, 2 titanium abutments (transmucosal part of the implant) were replaced by either an unused standard abutment or a roughened titanium abutment. After 3 months of habitual oral hygiene, plaque samples were taken for differential phase-contrast microscopy, DNA probe analysis, and culturing. Supragingivally, rough abutments harbored significantly fewer coccoid micro-organisms (64 vs. 81%), which is indicative of a more mature plaque. Subgingivally, the observations depended on the sampling procedure. For plaque collected with paper points, only minor qualitative and quantitative differences between both substrata could be registered. However, when the microbiota adhering to the abutment were considered, rough surfaces harbored 25 times more bacteria, with a slightly lower density of coccoid organisms. The presence and density of periodontal pathogens subgingivally were, however, more related to the patient's dental status than to the surface characteristics of the abutments. These results justify the search for optimal surface smoothness for all intra-oral and intra-sulcular hard surfaces for reduction of bacterial colonization and of periodontal pathogens.

Bacterial Adhesion↗
PubMed1993

Reproducibility and detection threshold of peri-implant diagnostics.

There is an increasing awareness that, for clinical monitoring of oral implants, there is a need for reliable diagnostics and possibly prognostic parameters. Indeed, reports have too often limited results to an inventory of failures, while no mention was made of progressive marginal bone loss or other symptoms of a future failure. Several parameters, such as marginal bone level assessment and/or probing attachment level, give a precision of up to 0.5 mm. Both measurements also seem related. The damping characteristics of the individual implant/bone unit also offer a highly reproducible diagnostic tool. The Periotest allows for detection of subclinical mobilities, and 95% of repeated measurements fall within a range of one unit on the arbitrary scale. So far, these three parameters offer no prognostic value.

Alveolar Bone Loss↗
PubMed1993

Clinical evaluation of a constant force electronic probe.

This study aimed to compare, in vivo, a conventional pocket probe with an automatic, computerized, constant force, electronic probe with a discrimination ability up to 0.1 mm. Sixteen adults with moderate chronic periodontitis and free of supra- and subgingival calculus participated in this study. Eight patients were examined by 2 investigators who used both the conventional and the automatic probes, for a total of 4 probings per subject. The remaining 8 patients were examined 4 times by investigator 1, twice with each probe. For each patient the Ramfjord teeth were examined and 6 sites were considered per tooth. Although the pocket depth measurements recorded by the manual probe were consistently deeper than those of the electronic probe, a good correlation was found between both recordings. Moreover, intra- and inter-examiner comparisons showed comparable standard deviations for both probes and small differences in absolute scores. The conventional probe was slightly more reproducible whereas the automated probe had the advantage of automatic registration. The results indicate that both probes can be considered as valuable in clinical practice.

Adult↗
PubMed1993

Periodontal indices around natural and titanium abutments: a longitudinal multicenter study.

This multicenter prospective study on the use of an implant system involved 9 centers and reports on the periodontal aspects after 3 years of observation. A total of 558 implants in 159 patients with 197 bridges all independent from natural teeth were originally included. Because of failures and patient withdrawals the number of implants was reduced to 460 and bridges to 174. The cumulative success rate for implants, starting from implant placement, is 94.3% after 2 years and 93.9% after 3 years indicating a leveling of implant loss. Failures concentrated in patients with a high plaque index. The loss of marginal bone was during the second and third years only 0.03 mm per year as an average while it was 0.4 mm during the first year. There were no reports of intense gingival inflammation in any of the patients and the plaque and gingivitis index behaved similarly around abutments and teeth. The probing pocket depth was significantly reduced over the observation time. The resistance towards marginal bone loss around these implants confirms the previous studies on fully edentulous patients.

Adolescent↗
PubMed1993

Subgingival minocycline hydrochloride ointment in moderate to severe chronic adult periodontitis: a randomized, double-blind, vehicle-controlled, multicenter study.

The safety and efficacy of subgingivally-applied 2% minocycline ointment was evaluated in a randomized, double-blind study of 103 adults with moderate to severe periodontitis. Two groups were compared; one received the test minocycline ointment and the other a vehicle control. Both groups had scaling and root planing at baseline, after which the test or control ointments were applied with an applicator into the periodontal pockets at baseline, and at 2, 4, and 6 weeks. Assessment of clinical response was made by measuring probing depth and probing attachment level and gingival bleeding. These measurements were made at baseline prior to scaling and root planing, and at weeks 4 and 12. Microbiological assessment of the subgingival flora was carried out with DNA probes at baseline, and at weeks 2, 4, 6, and 12 to identify and quantify Porphyromonas gingivalis, Prevotella intermedia, and Actinobacillus actinomycetemcomitans. Subgingival minocycline ointment resulted in statistically significantly greater reduction of P. gingivalis at weeks 2, 4, 6, and 12; P. intermedia at weeks 2, 4, 6, and 12; and A. actinomycetemcomitans at weeks 6 and 12. Probing depth reductions were seen for both groups at weeks 4 and 12; however, this reduction was statistically significantly greater in subjects treated with minocycline ointment. Reduction in gingival index and probing attachment gain were seen in both groups, however, the differences between the groups were not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1993

Comparison between implant-supported prostheses and teeth regarding passive threshold level.

A passive threshold determination was carried out on 31 patients subdivided into four test groups according to different prosthesis types supported by osseointegrated implants. They were compared to a control group of 10 patients with nonrestored natural test teeth. Forces were generated by a solenoid-driven stimulating device, which was placed in contact with the implant or tooth prior to the actual force rise to avoid impact forces. The findings indicate that the threshold level of implants is 50 times higher than that of natural teeth when tapping is avoided, which might otherwise trigger distant receptors. Bone deformation triggering the periosteal mechanoreceptors is the most logical explanation for the sensation reported.

Adult↗
PubMed1992

Side asymmetry of the jaw jerk in human craniomandibular dysfunction.

The jaw jerk elicited by tapping the chin with a reflex hammer was electromyographically recorded in 14 patients with craniomandibular dysfunction, who were selected because of their strictly unilateral symptoms. Mandibular deviation, as measured by means of a kinesiograph, was on the same side as the pain. Neurological and neurophysiological investigations, including the recording of masseter motor potentials evoked by transcranial stimulation, showed normal function of the sensory and motor trigeminal nerve fibres. Latency and amplitude of the jaw jerk recorded in postural position and intercuspal occlusion were, respectively, longer and smaller on the affected side. In some cases the latency difference exceeded 1 ms, the limit usually considered significant for trigeminal neuropathy or brainstem lesions. Jaw-jerk asymmetry is probably due to facilitation on the side contralateral to mandibular deviation. In intercuspal occlusion, contralateral facilitation might be produced by a stronger input from muscle spindles and periodontal mechanoreceptors. In postural position, other factors probably intervene.

Adult↗