| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Features Section |
Arch Expansion
Immediate Post-expansion Changes Following the Use of the Transpalatal Distractor
Pinto PX, Mommaertts MY, Wreakes G, Jacobs WVGJA
Journal of Oral and Maxillofacial Surgery 2001; 59: 994–1000[Medline]
Purpose: This study analysed the immediate post-expansion positional changes of the maxillary halves resulting from the use of the transpalatal distractor (Surgi-Tec NV, Bruges, Belgium).
Patients and methods: Corticotomies were performed in the same way as surgically-assisted rapid palatal expansion, all from a buccal sulcus approach. Titanium abutment plates with box extension were placed horizontally in the vertical wall of the palatal vault overlying the second premolar root through a mucoperiosteal incision and fixed with titanium screws 5 mm in length. An appropriate telescopic distraction module was fitted in the slots of the boxes. Expansion started 1 week after surgery, at a rate of 0.33 mm/day. Digital measurements on digital photographs of the models were obtained from 20 post-adolescent patients before and immediately after transpalatal distraction. The distractor was placed at the level of the second premolar. Pterygo-maxillary separation was not performed. Changes in the inter-canine, inter-premolar, and inter-molar width, in the dental arch perimeter, and in the premolar and molar angulations in the frontal plane were analysed and correlated.
Results: Width expansions of 35.7, 31.7, and 22.7 per cent were noted in the canine, premolar, and molar regions, respectively. There was a mean increase of the arch perimeter of 10.5 per cent, which correlated well (P < 0.001) with the expansion at the canine and premolar level. The mean angulation changes in the frontal plane of the premolar and molar segments were minimal, –8.3 ± 9.6 and 0.9 ± 9.9 degrees, respectively. The change in angulation at the molar level correlated (P < 0.005) with the amount of expansion in that region. Premolar angulation did not correlate with the expansion, and segment angulation did not correlate with age.
Conclusions: The expansion at the canine level was 1.5 times greater than at the molar level (corrected value relative to the original inter-molar width). The change in arch perimeter can be predicted from the expansion at the canine and premolar level. Expansion in the frontal plane occurs with little tipping of the segments.
Comment: This prospective clinical study was based on 20 consecutively treated patients aged 14–30 years, with an average age of 21.5 years. No orthodontic appliances were used. The paper includes a clear description of the experimental method, but falls down on the lack of raw data, a point clearly noted in the discussion of the paper written by Professor Proffit. According to the authors, as the distractors are bone-borne the expansion effects were different to those reported with either Rapid Maxillary Expansion (RME) or surgically assisted-RME. Greater expansion was noted in the canine than in the molar region and relatively little tipping of the dentition occurred.
Implants for Orthodontic Anchorage
Short Epithetic Implants for Orthodontic Anchorage in the Paramedian Region of the Palate
Bernhart T, Freudenthaler J, Dortbudak O, Bantleon H-P, Watzek G
Journal of Clinical Oral Implantology Research 2001; 12: 624–631
Objectives: To evaluate the efficacy of short epithetic implants for orthodontic anchorage in the paramedian region of the palate.
Study design: A prospective clinical trial.
Methods: Twenty-one patients had implants placed in the paramedian region of the palate. After a mean period of 4 months of unloaded healing the implants were subjected to either direct or indirect orthodontic loading.
Results: No implants were lost during the healing period, although three were considered as failures during the subsequent loading period. The time related survival probability was 85.8 per cent after 22.9 months.
Conclusions: Short epithetic implants are suitable to achieve maximum anchorage in the paramedian region of the hard palate in orthodontic treatment.
Bone grafting in clefts
Bone Volume after Secondary Bone Grafting in Unilateral and Bilateral Clefts Determined by Computed Tomography Scans
Van der Meij AJW, Baart JA, Prahl-Andersen B, Valk J, Kostense PJ, Tuinzing DB
Oral Surgery, Oral Medicine. Oral Pathology, Oral Radiology, Endodontics 2001; 92: 136–141
Objective: The purpose of this study was to evaluate the outcome of bone grafts in cleft palate patients, thus assessing the amount of bone necessary to facilitate eruption—especially in the buccopalatal direction—of the permanent canine into the bone graft.
Study design: Computer tomography scans taken immediately post-operatively and 1 year post-operatively of 42 unilateral and of 8 bilateral cleft lip and palate patients who underwent surgery at the age of 9 years (early secondary bone graft) or 12 years (late secondary bone graft) were compared. Three slices from the computer tomography scans taken immediately after the surgery were selected from the centre of the bone graft and were then compared with corresponding slices from the 1-year post-operative computed tomography scans. Statistical analysis was performed by using the Wilcoxon two-sample Rank Sum test.
Results: In the unilateral cleft group, 70 per cent of the transpalatal bone remained in the cleft area after 1 year, whereas in the bilateral cleft group, only 45 per cent of the initial bone graft remained after 1 year.
Conclusion: No statistically significant difference was found between early secondary bone grafting and late secondary bone grafting. In most cases, a sufficient amount of bone was present in the target area to facilitate eruption of the permanent canine.
Erosion of Enamel
The Erosive Effect of Herbal Tea on Dental Enamel
Brunton PA, Hussain A
Journal of Dentistry 2001; 29: 517–520[Medline]
Objectives: The aim of this study was to determine whether conventional black tea and a herbal tea were capable of eroding dental enamel. A further aim was to investigate whether herbal tea of the type tested eroded dental hard tissues to a greater or lesser extent than conventional black tea.
Methods: Three groups of 21 teeth were exposed to a conventional black tea Typhoo® (Group A), a herbal tea Twinings® Blackcurrant, Ginsing and Vanilla (Group B), and water, which acted as a control (Group C). Sequential profilometric tracings of the specimens were taken, superimposed, and the degree of enamel loss calculated as the area of disparity between the tracings before and after exposure.
Results: Conventional black tea and herbal tea, of the type tested, both resulted in tooth surface loss. Tooth surface loss, which resulted from exposure to herbal tea (mean 0.05 mm2, SD 0.02), however, was significantly greater (P = 0.00) than that which resulted from exposure to conventional black tea (mean 0.01 mm2, SD 0.00) and water (mean 0.00 mm2, SD 0.00).
Conclusions: It was concluded that herbal tea and conventional black tea of the type tested result in erosion of dental enamel. The erosive effect of the herbal tea of the type tested was five times that that of the conventional black tea tested. The cumulative effects of regular consumption of herbal tea of the type tested are likely, therefore, to be of clinical significance.
Comment: The specimens were immersed for 14 days in the test solutions, which, as pointed out in the article, approximates to the equivalent of an individual drinking four cups a day for 18.4 years taking an average of 15 sips, each lasting 3 seconds. Food for thought!
| ||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
