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At least 19 recordsLinked to original sources

Use of an incisor diagnostic triangle for evaluating incisor positions relative to the APo line.

Angular values of the upper and lower incisors to the APo line were measured in a sample of fifty subjects with clinically acceptable occlusions, ranging from 10 to 14 years of age. Correlations were high between both upper and lower incisor angulations to the APo line and the interincisal angle. The correlation was low between the upper incisor angulations to the APo line and the lower incisor angulations to the APo line. An incisor diagnostic triangle was introduced. This is made up of the interincisal angle and the intersection of the long axes of the upper and lower incisors to the APo line. Incisor diagnostic templates were introduced and their uses as diagnostic and visual aids were enumerated. These templates were constructed by using an idealized linear position of the tip of the lower incisors on the APo line, the upper incisor angulation to the APo line, and the interincisal angle. By relating both incisors to the APo line and to each other through the interincisal angle, the orthodontist is provided with a simple, specific diagnostic aid. The incisors are positioned in relation to a skeletal reference line (APo) which is more intimately associated with the patient's facial profile than more distant skeletal reference lines or planes, such as sella-nasion, Frankfort horizontal, or the mandibular plane.

Adolescent

Bilateral dens invaginatus in the mandibular incisor region.

A case of bilateral dens invaginatus in the mandibular incisor regions has been reported. Radiographs demonstrated invaginations in both of the incisors in the mandibular incisor region and also demonstrated a periapical radiolucency. Clinical examination revealed two anomalous incisors and apparently there was congenital absence of two mandibular incisors. Dens invaginatus in the mandibular incisors would appear to be a most unusual occurrence.

Adult

The orthodontic center of rotation of the maxillary central incisor.

The cephalometric records of sixty-four Class II, Division 1 cases treated exclusively with removable orthodontic appliances have been used in a study of the manner in which maxillary central incisors tilt. The center of rotation was most frequently located in the middle third of the incisor root. The longer the time interval between the pre- and posttreatment cephalograms, the more apical was the rotation axis likely to be, an effect ascribed to growth changes in the maxilla. If the effects of growth are taken into account, it seems that the maxillary central incisor seldom, if ever, tilts about the apical third of its root when force levels customarily recommended for tipping movements are employed. The results suggest that the instantaneous and orthodontic centers of rotation are one and the same and support the view that the manner in which incisor teeth move in response to a single applied force depends principally on the physical properties of the tooth root, supporting bone, and periodontal membrane. An unexplained correlation was found between the rate of incisor movement measured at the cervical margin of the tooth and the level of the rotation center.

Adolescent

The mandibular dental arch: Part I, lower incisor position.

The position of the lower incisor with respect to hard tissue references has been evaluated. Two samples were used for this purpose: one containing 78 patients with posttreatment records having a postretention period of at least 4 years, and the other composed of 82 normal occlusions. The results indicated: 1) There was no significant difference in relapse of lower incisor crowding between cases where the lower incisor had been moved lingually, labially, or held in the same relative position during treatment. 2) The position of the maxilla should be considered when placing the lower incisor. The APo plane adequately serves as a guide to this purpose, whereas other reference lines such as mandibular plane or facial plane do not. 3) The positions of the incisors with respect to popular cephalometric reference lines such as APo, NB, or mandibular plane were not correlated with the relapse of mandibular crowding. Therefore, other clinical guides might be more successful for determining stability.

Dental Arch

Mucogingival changes resulting from mandibular incisor tooth movement.

This study involved a cephalometric analysis of 1,150 fully treated orthodontic cases evaluated by Kodachrome slides, plaster casts, and cephalometric films to determine changes in the width of keratinized gingiva relative to lower incisor tooth movement and to ascertain the incidence of mucogingival problems in orthodontic patients. It was apparent that in a small percentage of cases visible mucogingival changes occurred and could be statistically correlated with the magnitude and direction of tooth movement. In this group of patients 1.3 percent (sixteen) showed a decrease in the width of keratinized gingiva with either minimal movement or some labial movement of the mandibular incisors; 0.69 percent (eight) had an increase in keratinized gingival width concomitant with significant lingual positioning of the lower incisors. The salient point to be made is that with an initial minimal or inadequate width of keratinized gingiva (0 to 2 mm.), mandibular incisor tooth movement over a period of treatment could significantly affect the final quality of gingival health in the critical mandibular anterior region.

Cephalometry

Relationship of the incisive papilla to the maxillary central incisors.

The average distance between the most anterior point of the maxillary central incisors and the most posterior point of the incisive papilla was 12.454 mm with a standard deviation of 3.867 mm. This distance was measured when these two points were projected on a plane which was parallel to the reference plane formed by the tips of three interdental papillae; i.e., the papilla between two central incisors (A), between the first and second molars on the right side (R), and on the left side (L). The average error incurred due to inconsistency of the method employed was less than 3% or less than 0.372 mm for the position of the central incisor. It is believed that the application of this anatomic relation can provide a reliable point for arranging and checking the position of the anterior maxillary teeth for complete dentures.

Denture Design

Clinical significance of supplementary innervation of the lower incisor teeth: a dissection study of the mylohyoid nerve.

In view of the relevance of the mylohyoid nerve to clinical difficulties in achieving deep analgesia of the lower incisors, a dissection study was undertaken. Dissection from twenty-six adult cadavers of both sexes were studied with the aid of a dissecting microscope. The following observations were made: (1) A supplementary branch of the mylohyoid nerve entered the mandible through accessory foramina in the lingual side of the mandibular symphysis in 50% of the cases. (2) It generally arose from the right side (76.9%) and entered the inferior retromental foramen (84.6%). (3) The mylohyoid nerve branch either ended directly in the incisor teeth and the gingiva or joined the ipsilateral or contralateral incisive nerve. In view of this information concerning the high incidence of possible involvement of the mylohyoid nerve in mandibular sensory innervation, it is advisable to block it whenever intervention in the lower incisors is indicated. Routine mylohyoid injection is recommended after mental nerve block. If the inferior alveolar nerve is chosen for anesthetic purposes, additional mylohyoid injection should be given only if pain persists. The mylohyoid injection should be given at the inferior retromental foramen on the median aspect of the inferior border of the mandible through extraoral approach.

Adult

Prevalence of upper lip posture and incisor overjet.

1,159 children (612 girls and 547 boys) aged 11-12 years were examined to determine the range and mean overjet values in four defined upper lip-maxillary central incisor relationships. No clinically significant differences were found on comparison of the data relative to each upper lip position. The findings suggest that upper lip posture is adaptive to the maxillary central incisor angulation and that the upper lip musculature is unlikely to influence the development of the incisor occlusion.

Child

Fractured and avulsed permanent incisors in Finnish children. A retrospective study.

The frequency of traumatic injuries to permanent incisors was studied in a sample of 1614 children from the city of Lahti in Southern Finland. The children, 801 girls and 813 boys, ranged in age from 6 to 16 years. Injuries to hard dental tissues and exarticulations of teeth were recorded. The prevalence of injuries was 19.8%--14.6% in girls and 25.0% in boys. A rapid growth in the prevalence rates was found at the ages of 9--11 years, at which the estimated mean annual incidence was about 5% in girls and 7% in boys. In 78.4% of the children with injured incisors, one tooth only was injured. The teeth most commonly injured were the upper central incisors, 81.7%; and the most frequent type of injury was an uncomplicated crown fracture, 90.5%.

Adolescent

Effect of Various Types of Remineralizing Agents on the Remineralization of Mild and Moderate Defects Caused by Molar-Incisor Hypomineralization in Mexican Schoolchildren: A 12-month Follow-up Randomized Clinical Trial.

PURPOSE: Using Laser-Induced Fluorescence (LIF), this study aimed to evaluate the effect of three remineralizing agents on permanent molars and incisors with both mild and moderate Molar-Incisor Hypomineralization (MIH) in 8-to-12-year-old Mexican schoolchildren. MATERIALS AND METHODS: In this randomized clinical trial, 104 children were selected to participate and then divided randomly into four groups: Group I: control, Oral-B kids (toothpaste); Group II: Fluor Protector (varnish); Group III: Clinpro White Varnish; and Group IV: MI Paste (CCP-ACP). Both varnishes were applied once every four weeks for twelve months for each group. Remineralization was evaluated by LIF at intervals of 1, 3, 6, 9, and 12 months. Paired-sample t-tests and repeated-measures ANOVA were performed, while the Greenhouse-Geisser correction was used to evaluate sphericity. RESULTS: The three test agents used increased the level of remineralization observed at the site of mild and moderate MIH defects over the course of twelve months (p0.001). A similar decrease in average LIF values was observed across the three treatment groups. CONCLUSIONS: The use of both fluoride varnishes and the CPP-ACP toothpaste was observed to promote the remineralization of both mild and moderate MIH defects.

Humans

A scanning electron microscope study of aberrations in the prism pattern of rat incisor inner enamel.

The prism pattern in the inner enamel of adult rat incisors was studied with the SEM in unfixed tissues that had been sectioned, ground, polished, and etched. Six different types of aberrations in the prism pattern were encountered: 1. Prism lamellae may be shorter than the mesio-lateral width of enamel. 2. Prism lamellae may deviate from a transverse orientation. 3. Prism lamellae may "fuse" or "bifurcate." 4. Prisms of two adjacent lamellae may pursue a common course. 5. Prisms may change direction. 6. Variations exist in the outline of transversely cut prism profiles. Aberrations were observed at any distance from the dentino-enamel junction. These observations were used as a basis for an analysis of the movement of ameloblasts during rat incisor amelogenesis. It was concluded that it is physically possible for the ameloblasts to create the observed aberrations as they move along the path of the prisms. However, the aberrations seem to make it more difficult to understand the factors controlling ameloblast movement. Occasionally crystallite bridges connecting adjacent prisms were observed. A configuration resembling a bifurcating prism is pesented.

Ameloblasts

Lower incisor extraction in orthodontic treatment.

The extraction of a single mandibular incisor can be employed as a compromise treatment of certain malocclusions, if the end result fulfills the requirements for a healthier dentition which is functionally and esthetically harmonized in relation to the surrounding structures. Indications, contraindications, and the procedure of treatment have been presented. Class I malocclusions with normal maxillary dentition and good buccal interdigitation in which there is severe lower anterior crowding are the best cases for this procedure, provided that the lower anterior arch length deficiency is greater than 4 to 5 mm. and the anterior tooth ratio is more than 83 mm. In conditions exhibiting a deep overbite pattern, reduction of the mandibular anterior unit should be avoided. Furthermore, I do not regard mandibular incisor extraction as a routine orthodontic procedure but, instead, consider it to be an almost last resort measure since it involves the most important stabilizing area of occlusion.

Adolescent

Management of cases with upper incisors missing.

A problem often confronting the orthodontist is that of missing upper incisors. In evaluation of the individual case, the dicision as to space closure or space regaining and eventual prosthetic reconstruction can be perplexing. Various diagnostic criteria, such as skeletal relation, arch-length analysis, inclination of teeth, and dental esthetics, must be evaluated. On the basis of this diagnostic information, treatment alternative is chosen to correct the malocclusion. The solution may be found in maintaining space, necessitating postorthodontic prosthetic replacement, or closing space and thus avoiding the need for artificial teeth. Four cases are shown to illustrate different approaches to the treatment of patients with upper incisors missing. Other solutions are possible anc correct. Each case must be weighed on its own merits.

Adolescent

Solitary maxillary central incisor and normal stature.

Two children, one boy and one girl, each with solitary maxillary deciduous and permanent central incisors, normal height, and normal plasma growth hormone levels, are reported. Review of the literature reveals fourteen reports of patients with a similar dental anomaly. Of these, three are normal in height. The height and growth rate of patients with a single maxillary central incisor should be evaluated prior to growth hormone evaluation; such investigation should be undertaken only if the height is two standard deviations below the mean or if there is evidence of plateauing of linear growth.

Abnormalities, Multiple

Mottled permanent incisors in 15-year-old Lagos children.

Mottled permanent incisors were studied in a stratified convenience sample of 206 Lagos schoolchildren aged 15 years. The mouth prevalence of this condition was 32%, and the right-left symmetry of the mottled incisors occurred very approximately in only a third of those persons with mottling. The distribution pattern was similar to that observed in similarly aged children in non-fluoride communities, and also that observed in optimally fluoridated Anglesey, England. The cause of this type of mottling in unknown, but its distribution suggests that endogenous (possibly genetic) factors may be involved.

Adolescent