“I believe, in a word, that the true scientific method confines the mind without suffocating it, leaves it as far as possible face to face with itself, and guides it, while respecting the creative originality and spontaneity which are its most precious qualities. Science goes forward only through new ideas and through creative or original power of thought. In education we must, therefore, take care that knowledge which should arm the mind does not overwhelm it by its weight, and that rules, intended to support weak parts of the mind, do not atrophy the strong and fertile parts”.
It has been postulated that subjects with high levels of oral sensory perception and motor ability are able to achieve higher standards of oral hygiene even under different dietary regimes. In this study, eleven dental personnel volunteers were started on a low-sucrose diet for one week, followed by a high-sucrose diet for another week, while eleven others followed a reverse-order dietary regime. Oral sensory perception and motor ability were assessed by the oral stereognosis test and a test for oral motor ability. There was a greater trend for subjects to have more plaque on their teeth when they were on the high-sucrose diet, even when normal oral hygiene procedures were taken. There were no significant correlations between the state of oral hygiene and levels of oral sensory perception and motor ability. These results do not support the hypothesis that subjects with high levels of oral sensory perception and motor ability are likely to achieve better oral hygiene.
A study was conducted to evaluate the effects of local drug delivery on subgingival plaque flora using hydroxypropylmethylcellulose (HPMC) and methylcellulose (MC) base material containing 40 % doxycycline (DOXY). Eleven patients who had at least four pockets exceeding 5 mm in depth associated with a single rooted tooth were selected from volunteers after an initial examination. Two of the pockets were chosen at random for insertion of the HPMC and MC strips twice a week for 6 w. One pocket received no treatment, and the other was debrided and root-planed only. Baseline and follow-up measurements at 0, 1, 3, 6, and 10 w included probing depth, gingival shrinkage, bleeding on probing and crevicular fluid flow. Subgingival bacterial samples were also taken for dark-field microscopy. In vitro drug release from the HPMC strips was greater than that from MC. Significant improvements in many clinical parameters occurred in the pockets treated with HPMC or MC strips, or mechanical debridement. There was a marked decrease in the relative proportions of motile organisms during and after treatment.
A study was carried out to compare the effects of subgingival applications of resorbable hydroxypropylmethylcellulose (HPMC) membranes containing 20% chlorhexidine (CHx) and 40% doxycycline (DOXY) placed subgingivally in periodontal pockets greater than 5 mm in depth. Each of 11 patients had at least four pockets. HPMC strips containing CHx and DOXY were inserted into each pocket twice a week for 6 w. One pocket was kept as a control and the other received subgingival scaling and root planing at 0, 1, 3 and 6 w. The microbial flora of 44 pockets from the 11 patients was examined using dark-field microscopy at the baseline and at 1, 3, 6 and 10 w. Clinical parameters including probing depth, crevicular fluid flow, bleeding on probing and gingival shrinkage were also recorded. The CHx and DOXY-administered or root-planed pockets showed marked reduction of both pocket depth and the number of motile organisms. Less bleeding was also observed in CHx and DOXY-inserted pockets.
A study was conducted to observe the effectiveness of an EDTA-based agent, Tubulicid Red, and a polyacrylic acid-based agent, Dentin Conditioner, for removal of the smear layer from a prepared dentin surface, with or without a fluoride dentin reinforcing agent, using the dye penetration test and scanning electron microscopy (SEM). Bovine mandibular first and second incisors were used. After removal of the enamel, the smear layer on the dentin surface was treated with 38% H3PO4, Tubulicid Red, Dentin Conditioner, 1% NaF, 1% SnF2, Tubulicid Red (including 1% SnF2), Dentin Conditioner (including 1% NaF) and Dentin Conditioner (including 1% SnF2). In the dye penetration test, Dentin Conditioner (including 1% SnF2) was the most effective agent for preventing dye penetration. SEM evaluation of the dentin surface after treatment with the smear layer removal agents and/or fluorides showed that the smear layer was removed by H3PO4 and Dentin Conditioner. However, dentinal plugs remained after treatment with Dentin Conditioner alone. The other agents left some layers on the dentin surface.
A study was conducted to investigate subgingival plaque formation on two types of dental implant material in the human oral cavity. Fifteen teeth affected by severe periodontitis and scheduled for extraction in five patients were selected. After thorough root planing, inlay cavities were prepared from the gingival margin to 5 mm subgingivally. Then, rectangular test specimens (polycrystal aluminum ceramic (P), single-crystal aluminum ceramic (S)) or a control dentin specimen (D) were installed in gold inlays, which were placed in the inlay cavities and left for 3, 7 or 21 d. As a consequence, 4 mm of the surface of each specimen was exposed to the environment of the periodontal pocket. After each test period, the specimens were removed from the inlays and examined by scanning electron microscopy (SEM). The results suggested that S is a more suitable dental implant material than P from the viewpoint of clinical application because of its lower degree of plaque accumulation.
According to the authors' clinical experience, malocclusion accompanied by temporomandibular joint disorder involves mainly cross bite, open bite, deep overbite or axillary protrusion. However, it is possible that the symptoms of this disorder are associated with other types of malocclusion or even with nearly normal occlusion. In fact, it can be said that temporomandibular joint disorder may develop with any type of occlusion. This paper reports a case of open bite accompanied by temporomandibular joint disorder occurring in a patient who visited our hospital because of pain in the left temporomandibular joint region, vertigo and partial deafness. In this patient, the temporomandibular symptoms disappeared after orthodontic treatment. The patient received no particular treatment thereafter because follow-up observation confirmed that the therapeutic results were favorable without any relapse of the symptoms of temporomandibular disorder. The positions of the temporomandibular joint and mandibular condyle were determined in lateral-oblique radiograms obtained using our radiographic system, by which the mandibular condyle is radiographed using a projection consistent with its long axis.