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Mandibular Arch (mandibular + arch)

Distribution by Scientific Domains

Medical Sciences	90%

Selected Abstracts

Dental arch morphological and dimensional characteristics in Jordanian children and young adults with ,-thalassaemia major

INTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 2 2005
A. AL-WAHADNI
Summary. Objective. , The aim of this study was to examine the arch dimensions of Jordanian patients with ,-thalassaemia major in comparison with an unaffected control group. Methods. , The sample consisted of 24 patients who suffered from ,-thalassaemia major (mean age = 13·9 ± 3·1 years) and an unaffected control group (mean age = 13·5 ± 2·9 years) matched for dental age, sex, and incisor and molar relationships. The unaffected control group was randomly selected from four public schools in the Governate of Irbid-Jordan. Alginate impressions were taken of the maxillary and mandibular dental arches of all participants. All measurements of the arch dimensions were made on the casts using an electronic digital sliding calliper. Results. , In the mandibular arch, when compared with the patients with thalassaemia, the unaffected control group subjects showed a (statistically) significantly larger incisor width, larger arch depth, and larger left and right anterior arch lengths (1·18, 2·58, and 1·85 and 1·12 mm, respectively). In the maxillary arch, there was a statistically significant difference in the mean incisor width (± 2·16 mm), arch depth (± 3·14 mm), inter-molar width (± 1·21 mm) and in the left anterior arch length (± 1·97 mm). The canine widths, premolar widths, left and right posterior arch length, and curve of Spee of both arches showed no statistically significant differences between the two groups. Conclusion. , When compared to unaffected subjects, patients with ,-thalassaemia major exhibited: a narrower maxilla; a shorter maxilla and mandible; and smaller incisor widths for the maxillary and mandibular arches. [source]

Evolution of the vertebrate jaw: comparative embryology and molecular developmental biology reveal the factors behind evolutionary novelty

JOURNAL OF ANATOMY, Issue 5 2004
Shigeru Kuratani
Abstract It is generally believed that the jaw arose through the simple transformation of an ancestral rostral gill arch. The gnathostome jaw differentiates from Hox -free crest cells in the mandibular arch, and this is also apparent in the lamprey. The basic Hox code, including the Hox -free default state in the mandibular arch, may have been present in the common ancestor, and jaw patterning appears to have been secondarily constructed in the gnathostomes. The distribution of the cephalic neural crest cells is similar in the early pharyngula of gnathostomes and lampreys, but different cell subsets form the oral apparatus in each group through epithelial,mesenchymal interactions: and this heterotopy is likely to have been an important evolutionary change that permitted jaw differentiation. This theory implies that the premandibular crest cells differentiate into the upper lip, or the dorsal subdivision of the oral apparatus in the lamprey, whereas the equivalent cell population forms the trabecula of the skull base in gnathostomes. Because the gnathostome oral apparatus is derived exclusively from the mandibular arch, the concepts ,oral' and ,mandibular' must be dissociated. The ,lamprey trabecula' develops from mandibular mesoderm, and is not homologous with the gnathostome trabecula, which develops from premandibular crest cells. Thus the jaw evolved as an evolutionary novelty through tissue rearrangements and topographical changes in tissue interactions. [source]

Thickness of gingiva in association with age, gender and dental arch location

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 7 2005
K. L. Vandana
Abstract Background: It has been long known that the clinical appearance of healthy marginal periodontium differs from subject to subject and even among different tooth types. Many features are genetically determined; others seem to be influenced by tooth size, shape and position and biological phenomena such as gender, growth and age. Aim: The purpose of this study was to determine the thickness of facial gingiva among Indians and its association with age, gender and dental arch. Methods: The study group included 16 males and 16 females with an age range of 16,38 years. Gingival thickness was assessed in the maxillary and mandibular anteriors by transgingival probing. Results: It was observed that the younger age group had significantly thicker gingiva than that of the older age group. The gingiva was found to be thinner in females than males and, in the mandibular arch than the maxilla. Conclusion: In the present study, it was concluded that gingival thickness varies according to age, gender and dental arch. [source]

In vivo mandibular elastic deformation during clenching on pivots

JOURNAL OF ORAL REHABILITATION, Issue 2 2002
Ting Jiang
Lower rigidly connected long span bridges supported by natural abutments or implants sometimes become loose, come off, or fracture after a period of usage. Many reasons have been discussed for these failures. However, few researchers have shown the influence of mandibular elastic deformation on the abutments, although this influence is likely to produce a distortion force between the abutment and prosthesis. Therefore, this study measured the elastic deformation of the human mandibular arch during clenching on pivots by using charge-coupled device (CCD) cameras and an image analysing system. When the subjects clenched on the canines (unilaterally or bilaterally) or bilateral second molars, no mandibular deformation was found; whereas when the subjects clenched on the unilateral second molars, the mandibular arch on the non-pivot side moved upward and inward and the straight line distances between the right and left measurement points decreased by 0·2 mm. The magnitude of deformation is smaller than the depressible limit of periodontal membrane. This suggests that the influence of mandibular deformation on the connected prosthesis is negligible in the case of the natural root supported long span bridge but should probably be considered in the case of the implant supported bridge. [source]

Periodontal condition of the mandibular anterior dentition in patients with conventional and self-ligating brackets

ORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 4 2008
N Pandis
Structured Abstract Authors,,, Pandis N, Vlachopoulos K, Polychronopoulou A, Madianos P, Eliades T Objectives,,, To explore whether the use of self-ligating brackets is associated with better values for periodontal indices because of the lack of elastomeric modules and concomitantly, reduced availability of retentive sites for microbial colonization and plaque accumulation. Setting and Sample Population,,, Private practice of the first author. Patients were selected using the following inclusion criteria: age range 12,17 years, fixed appliances on both arches, aligned mandibular arch, and absence of oral habits and anterior crossbites. Materials and Methods,,, Prospective cohort investigation. Participants were grouped for bracket type, thus 50 patients formed the conventional bracket cohort and 50 patients the self-ligating bracket cohort. Both cohorts were followed with the purpose to examine periodontal status. Average length of follow-up was 18 months. This time period was considered adequate for a proportion of study participants to experience the outcome of interest. Outcome variables were plaque index, gingival index, calculus index, and probing depth for the two bracket cohorts. Results,,, No difference was found in the indices recorded between the two bracket cohorts studied. Conclusion,,, Under the conditions as applied in this study, the self-ligating brackets do not have an advantage over conventional brackets with respect to the periodontal status of the mandibular anterior teeth. [source]

Dental arch morphological and dimensional characteristics in Jordanian children and young adults with ,-thalassaemia major

Hereditary gingival fibromatosis: a case report

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 9 2002
Isabel Poiares Baptista
Abstract Background/Aims: Hereditary gingival fibromatosis is characterized by various degrees of attached gingival overgrowth. It usually develops as an isolated disorder but can be one feature of a syndrome. A case of a 38-year-old female is reported who presented a generalized severe gingival overgrowth, involving the maxillary and mandibular arches and covering almost all teeth. The clinical differential diagnosis included drug-induced overgrowth as well as idiopathic gingival fibromatosis. Treatment: Excess gingival tissue was removed by conventional gingivectomy. As the gingival enlargement was generalized to all quadrants, on both sides, the surgery was carried out under general anaesthesia. The postoperative course was uneventful and the patient's appearance improved considerably. Post-surgical follow-up after 20 months demonstrated a slight recurrence Conclusions: Hereditary gingival fibromatosis is a rare disorder characterized by the proliferative fibrous overgrowth of the gingival tissue. Resective surgery of the excess tissue is the treatment available. However, recurrence is a common feature. [source]

TOOTH WHITENING IN CHILDREN

JOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 6 2005
K.J. Donly
ABSTRACT Objective: This clinical study evaluated the efficacy and tolerability of tooth whitening in children and adolescents, using a marketed, tray- based tooth-whitening system and a disposable polyethylene strip system. Materials and Methods: A study population of 106 children and adolescents, ages 11 to 18 years, participated in this study. There were 61 girls and 45 boys, with a mean age of 14.7 years. Subjects were divided into two experimental treatment groups, the groups being balanced with respect to demographic characteristics and baseline tooth color. All subjects had to have all permanent anterior teeth erupted, a baseline Vita shade (Vita Zahnfabrik, Bad Säckingen, Germany) score of A2 or darker, and the desire to whiten their teeth. One experimental group included 71 subjects who used a 6.5% hydrogen peroxide strip system (Crest Whitestrips Professional Strength, Procter & Gamble, Mason, OH, USA) for 30 minutes twice daily. The other experimental group included 35 subjects who used a 10% carbamide peroxide tray system (Opalescence, Ultradent Products, South Jordan, UT, USA) overnight. Subjects who had previously vital bleached their teeth, exhibited apparent caries or periodontal problems, had orthodontic appliances or anterior restorations, or reported dentin hypersensitivity were excluded. The study population was treated in two separate cohorts, by two independent investigations, to minimize the effects of examiner bias. Digital images were collected for all subjects at baseline, 2 weeks, and 4 weeks, with the maxillary and mandibular arches being treated separately for 4-week intervals. An oral examination was conducted at baseline and at all recall intervals. Subjects reported any adverse events in interviews. Color change was calculated from digital images where L* indicated lightness, a* redness, and b* yellowness. Comparisons between the two experimental groups were made using a two-sided analysis of covariance with a 5% significance level. Results: Both experimental systems exhibited significant (p < .001) tooth-whitening improvement relative to the baseline. Color change was greater in the maxillary teeth than in the mandibular teeth for both systems evaluated. The color change for maxillary teeth was not significantly different between the two systems evaluated; however, the tray system demonstrated significantly (p < .05) greater toothwhitening effectiveness for the mandibular teeth. Both treatment regimens were well tolerated. Minor tooth sensitivity and oral irritation were the most commonly reported adverse events, being reported by 49% of the subjects assigned to the strip group and 43% of the subjects in the tray group. All reported that adverse events were relieved immediately upon discontinuance of product use. Conclusion: The 6.5% hydrogen peroxide gel strips and the 10% carbamide peroxide gel delivered overnight in customized trays effectively whitened teeth, and both treatment regimens were well tolerated. [source]

Influence of surgical repositioning of mature permanent dog teeth following experimental intrusion: a histologic assessment

DENTAL TRAUMATOLOGY, Issue 6 2002
R. F. Cunha
Abstract,,, The aim of this study was to evaluate, through histologic examination, the effect of surgical repositioning of intruded dog teeth upon the pulpal and surrounding tissues. Thirty teeth in 10 adult dogs, aged 2,3 years, were used. Fifteen teeth were intruded, surgically repositioned and fixed using orthodontics wire, composite resin, and enamel acid conditioning. All these teeth served as the experimental group. The remaining intruded teeth were not treated (control group). The animals were sacrificed to allow observations at 7, 15, and 30 post-operative days. The maxillary and mandibular archs were removed and processed for histologic exam. Based on the methodology and observed results, we concluded that: pulpal necrosis, external root resorption and ankylosis were common sequelae to severe traumatic intrusion; a careful immediate surgical repositioning of severed intruded permanent tooth with complete root formation has many advantages with few disadvantages. [source]