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Biomedical subjects

J Waerhaug

Publications and source records attributed to J Waerhaug.

At least 19 recordsLinked to original sources

Healing of the dento-epithelial junction following the use of dental floss.

The healing of the dento-epithelial junction following the use of dental floss was studied on 28 first premolars in seven children who were under orthodontic treatment. On the mesial surfaces the floss was brought to the depth of the pocket and moved back and forth three to five times, while being pressed against the tooth surface. After observation periods varying between 15 min and 3 weeks, the teeth were extracted and stained in a 1% solution of Water Blue and examined under the stereomicroscope. All the distal surface (control) were found to be covered with a more or less continuous layer of junctional epithelial cells, whereas on the mesial surface (experimental), these cells were absent after 15 min and 24 h, i.e. they had been detached by the floss. New epithelial cells were found to reattach to the enamel after 3 days, and after 2 weeks and more, the cell population on the experimental surfaces could not be distinguished from that on the control surfaces. In one patient in whom the floss had been used daily for 3 1/2 months, there had for obvious reasons been no reattachment of junctional epithelial cells to the enamel, but there was nothing to indicate that the flossing had had unfavorable consequences.

Child↗

Effect of toothbrushing on subgingival plaque formation.

The purpose of the present study was to find out to what extent subgingival plaque formation may be prevented by toothbrushing. The experiment was carried out on a total of 28 molars in four monkeys. On day 0 all supra- and subgingival deposits were removed, and during the following year, the teeth on the left side were carefully brushed three times a week, employing the Bass' method. The right side was kept as unbrushed control. The histologic sections, which were cut in a bucco-lingual direction, showed that subgingival plaque almost invariably had developed on the unbrushed teeth. Although all of the brushed teeth were free of subgingival plaque, a mild to moderate cellular infiltration prevailed for some distance below the gingival margin. These inflammatory reactions were assumed to have been induced by the bristles of the toothbrush, which were shown to penetrate as far as 0.9 mm below the gingival margin, when employing the Bass method. It was concluded that subgingival plaque formation can be prevented in areas accessible to the toothbrush.

Animals↗

Eruption of teeth into crowded position, loss of attachment, and downgrowth of subgingival plaque.

The role of crowded teeth in the etiology of attachment loss was studied in thirty teeth extracted for orthodontic reasons from eight children 12 to 13 years of age. Following extraction, the teeth were stained in a 1 percent solution of water blue and examined under the stereomicroscope. In one third of the thirty teeth, a 0.9, 2.0, and 3.5 mm. loss of attachment was observed on surfaces adjacent to which another tooth had erupted into an extremely crowded environment. On the same surfaces, subgingival plaque had grown down to the area of the cementoenamel junction. The premature loss of attachment was assumed to be mediated by collagenase derived from the regressing dental organ or from the junctional epithelium surrounding the erupting teeth. The premature downgrowth of subgingival plaque to the area of the cementoenamel junction was facilitated by the development of an irregular contact line within the interdental papilla, rather than a contact point above the papilla.

Adolescent↗

Temporary restorations: advantages and disadvantages.

The reaction of tissue to temporary restorations was studied in four young dogs and four young monkeys. A total of 56 cavities were prepared and filled with gutta percha, self-curing acrylic resin, or zinc oxide and eugenol cement. Attempts were made to finish the preparations at the deepest point of the existing clinical pocket, which invariably was found to coincide with the cemento-enamel junction. All the animals had the teeth on the left side brushed every day. The observation periods varied between 13 and 283 days. Immediately before the animals were killed by an overdose of Nembutal, the presence or absence of gingivitis was recorded. A series of sections were cut in the area of the cavity, as well as just outside it. The following observations were made: Examination of the sections from outside the cavities verified that the preparations had been made in pockets with soft walls made up of the junctional epithelium. The cavities ended shortly above the cemento-enamel junction (Figs. 3, 4, 6, and 8) or below it (Figs. 1, 2, 5, 7, and 9 to 11). The adaptation of the fillings was never perfect in all parts of the cavity at the same time. The pocket epithelium was regenerated within 13 days. Plaque formation first started in the open spaces between the preparation and the fillings. Subsequently, the plaque spread over the surfaces of the fillings and eventually over the tooth surface below them. The fillings invariably induced submarginal gingivitis, even in the absence of plaque. Presence of plaque exacerbated the inflammatory reaction, but the loss of attachment was limited to less than 0.2 mm as long as the plaque was confined to the fillings. Significant loss of attachment was always associated with apical growth of the subgingival plaque. The submarginal gingivitis was not manifested clinically if the fillings were brushed daily, because vigorous tooth brushing had an effect as far as 0.7 mm below the gingival margin.

Acrylic Resins↗

The angular bone defect and its relationship to trauma from occlusion and downgrowth of subgingival plaque.

Sixty-four sets of human teeth were collected with the aim of evaluating the role of trauma from occlusion in the etiology of destructive periodontal disease. Before the jaws were taken out, a careful bite analysis was carried out. After fixation of the jaws, impressions were taken and plaster of Paris models were made. Finally, a set of 14 radiographs were taken. On the basis of the "clinical" records postmortem, the study models and the radiographs, the jaws were sectioned. Only mesio-distal sections were included in the present analysis. The total number of interdental spaces examined was 106. The following observations were made: 1. Before any loss of periodontal fiber attachment has taken place, the configuration of the interdental septum is entirely dependent on the location of the cemento-enamel junction (CEJ) of the two neighboring teeth. The alveolar crest does not approach the apical border of the junctional epithelium closer than about 1 mm. Thus, if the CEJ is located at different levels on two neighboring teeth, the marginal termination of the interdental septum will be oblique, forming an acute angle with the "lowest" tooth. 2. Loss of periodontal fiber attachment could invariably be related to the apical growth of subgingival plaque, and downgrowth of plaque was always associated with an inflammatory process which involved lysis of the attachment fibers within a distance varying between 0.2 and 1.8 mm from the apical border of the plaque. Subsequently, the JE proliferated down to cover the denuded root surface. 3. Reduction in height of the alveolar crest could also be related to the downgrowth of plaque. The distance from plaque to bone was never found to be less than 0.5 mm and never more than 2.7 mm. The configuration of the interdental septum always seemed to be determined by the level of the plaque on the two neighboring tooth surfaces. Thus, if the plaque had reached the same level on both sides, the crest of the interdental septum assumed a horizontal outline; if plaque had proliferated down to different levels, the crest of the interdental septum was oblique and an angular defect hereby established. 4. In the present material no evidence was found to indicate that functional (traumatic) forces can act as a co-factor in the causation of angular defects. In fact, such defects were found equally often adjacent to "nontraumatized" as to "traumatized" teeth. 5. Infrabony pockets were invariably associated with downgrowth of subgingival plaque.

Dental Occlusion, Traumatic↗

The infrabony pocket and its relationship to trauma from occlusion and subgingival plaque.

The role of trauma from occlusion and subgingival plaque in the pathogenesis of the infrabony pocket as observed in the radiograph was studied in 48 teeth which had to be extracted because of advanced periodontal disease. Prior to extraction the teeth were examined with regard to the degree of mobility and the direction of the horizontal components of the masticatory forces. Following extraction, the teeth were stained and examined under the stereomicroscope. When the tooth is adequately stained, the subgingival plaque and the remaining attachment fibers can be distinguished easily from the area of the junctional epithelium. The observations which were made on the extracted teeth were then correlated with what could be seen in the radiograph. The following major observations were made: In the depth of the infrabony pocket there was a close congruence between the front of the subgingival plaque and the borderline of the remaining attachment fibers, the distance varying between 0.2 and 2.0 mm. There was also a close relationship between the front of the subgingival plaque and the alveolar crest adjacent to the tooth as well as between the surface of the subgingival plaque and the opposite vertical wall of the infrabony pocket, the distances ranging between 1 and 3 mm. The horizontal forces were mainly or exclusively oriented bucco-lingually, whereas the infrabony pockets were located mesially or distally, i.e. parallel to the direction of the force and not at a right angle to it as observed in experimental studies. The mobility of the teeth adjacent to which infrabony pockets developed was normal in 42% of the cases, slightly increased in 31%, and only in 11% of the cases was it excessively increased. In 19 cases the infrabony pocket was located on one of the roots of lower molars which were removed by hemisection. In eight of the 12 cases, which were observed for periods from 1 to 10 years, the remaining root functioned well without further development of angular bone defects or infrabony pockets. All of them became markedly firmer as a consequence of successful periodontal treatment. Three of the four remaining roots were extracted because of periapical problems. There was no evidence to indicate that trauma from occlusion had been involved in the pathogenesis of the infrabony pockets.

Adult↗

Plaque control in the treatment of juvenile periodontitis.

With the purpose of establishing to what extent "periodontosis" responds to total plaque control, 21 such patients were observed over periods ranging from 8 to 34 years. Total plaque control in the present context means complete removal of all supragingival plaque by the patient and complete removal of all subgingival plaque by the dentist. The results were evaluated in terms of the number of lost teeth and the percentage of lost attachment during the observation period. It was observed that "periodontosis" cases responded to total plaque control in the same way as do ordinary cases, but with periodontosis, incomplete plaque control on any teeth led to extremely rapid bone loss and eventually to extraction. The reason for this is the unusually rapid apical migration of the subgingival plaque which is the most typical feature of the juvenile periodontitis. Some attachment and some teeth were lost in most of the patients, but a sufficient number of teeth with a sufficient amount of supporting tissue were maintained to provide a set of natural teeth that functioned well. This study shows that the reduced resistance to the invasion of subgingival plaque can be compensated for by a correspondingly strong emphasis on total plaque control. The term "periodontosis" is misleading, and should be replaced by the name "juvenile periodontitis" as suggested by Lehner et al. (1974).

Adult↗

Subgingival plaque and loss of attachment in periodontosis as evaluated on extracted teeth.

The correlation between downgrowth of subgingival plaque and loss of attachment was evaluated on 27 teeth which had to be extracted because of advanced bone loss in 16 patients between ages 12 and 22. The diagnostic criteria were those used for periodontosis. The teeth were stained and examined under the stereomicroscope. There was a very high degree of congruence between the subgingival plaque front and the line of lost attachment on all the teeth, thus showing that plaque is strongly involved in the destruction of the attachment apparatus. On some of the vestibular and lingual surfaces where efficient supragingival plaque control had been maintained, there was no subgingival plaque and no loss of attachment, showing that subgingival plaque develops from supragingival plaque. The highest speed of apical growth of the subgingival plaque front in any one case was estimated to be about 5 mu per day, or about 1,8 mm per year. Such an unusually rapid advancement must be the combined effect of an extremely high invasiveness of some inhabitants of the plaque and some deficiency in the host's defense mechanism against the same organisms. The subgingival plaque was found to be very thin and only occasionally calcified to form calculus. Symptoms of inflammation, if any, were only seen at the gingival margin, giving the clinical impression of a noninflamatory, degenerative condition. This explains why the concept of diffuse atrophy has developed. The observations made in this material indicate that what has been diagnosed as periodontosis, in fact is a highly destructive juvenile periodontitis which should be so named. The high destructiveness depends on a host parasite imbalance rather than on a degenerative condition.

Adolescent↗

The interdental brush and its place in operative and crown and bridge dentistry.

The effect of the interdental brush was evaluated on sixty-seven extracted teeth which were stained and examined under the stereomicroscope. Thirty-one of the teeth were totally covered with plaque when the interdental brush was used on them immediately before extraction. Thirty-six of the teeth were from patients who had used the interdental brush routinely for several years. The interdental brush was found to have an excellent effect both in the central part of the interdental space and on the embrasures. However, the most noteworthy finding was that it removes plaque as far as 2-2 1/2 mm below the gingival margin. This means that restorations can be kept free of plaque, even if they are extended into the pocket. In modern dentistry 'extension for prevention of dental caries' has become a controversial principle because subgingival restorations retain plaque which induces destructive periodontal disease. In many cases this problem can be solved by introducing the interdental brush.

Crowns↗

Subgingival plaque and loss of attachment in periodontosis as observed in autopsy material.

Histologic sections from six autopsy cases which from a clinical point of view fitted into the criteria of periodontosis were examined with the aim at evaluating the role of subgingival plaque in the etiology of the loss of attachment in this condition. The following pertinent observations were made: 1. The subgingival plaque in most instances was not calcified to form calculus. 2. The thickness of the subgingival plaque varied between 20 and 200 mu (0.02-0.2 mm). 3. Where loss of attachment had taken place, the distance from the most apical part of the subgingival plaque to the most apical point of the epithelial cuff varied between 0.2 and 1.1 mm; this distance was never found to be more than 1.1 mm. This would indicate a cause and effect relationship, the plaque being the obvious cause. 4. There was very severe chronic inflammation in the soft tissue bordering upon the plaque with resulting collagenolysis. 5. The cellular infiltration and the collagenolysis may be limited to a zone of 1 to 2 mm in the immediate vicinity of the plaque. Between the inflamed area and the surface of the gingivae buccally and lingually there may be a fairly wide zone of healthy tissue which hides the symptoms of inflammation from being observed on a clinical examination. In turn this could leave the clinician with the impression that attachment has been lost and bone resorbed because of degenerative changes. The following conclusions can be made: In these six cases of "alveolar bone loss vastly out of proportion to what one would expect from the local etiologic factors in the patient at that age" there was no morphologic evidence that degenerative changes were responsible for the loss of attachment. On the contrary inflammatory changes induced by the subgingval plaque dominated the histopathologic picture.

Adult↗

A method for evaluation of periodontal problems on extracted teeth.

It is shown that many periodontal problems can be evaluated by examining stained, extracted teeth. Presence or absence of gignival inflammation around the tooth before extraction can be established after extraction on the basis of presence or absence of plaque. Loss of attachment and its relationship to local etiological factors can also be established. The method is particularly useful for experimental investigation on periodontal problems in man.

Adult↗