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At least 217 records · Page 12Linked to original sources

The effect of the position and orientation of unerupted premaxillary supernumerary teeth on eruption and displacement of permanent incisors.

The hospital records of 101 consecutive patients admitted for removal of premaxillary supernumerary teeth were examined. From the clinical notes and preoperative anterior occlusal radiographs the following information was noted: the position and orientation of the supernumerary teeth, and whether they caused delayed eruption, rotation or displacement of the associated permanent incisors. There were 140 supernumerary teeth (mean per child = 1.39). Delayed eruption of permanent incisors occurred in 56% of cases. Supernumerary teeth situated between central incisors caused eruption delay infrequently, but were associated with rotation and displacement of permanent incisors more frequently than those that overlapped the incisors on the radiographs. Supernumerary teeth that were orientated vertically caused eruption delay more frequently than those that were inverted, but the orientation of supernumerary teeth did not influence rotation or horizontal displacement of the permanent incisors.

Adolescent↗

A review of 47 cases of unerupted maxillary incisors.

OBJECTIVES: To study the prevalence of aetiological factors associated with unerupted maxillary incisors and to follow the outcome of treatment in a study of 47 cases. DESIGN: A retrospective study. SETTING: The Dental Department, St Luke's Hospital, Malta, the School Dental Clinic of Malta and the private practices of two orthodontists in Malta. SAMPLE AND METHODS: Forty-seven patients with a total of 53 unerupted maxillary incisors were classified according to the aetiological factors causing non-eruption. The relative prevalence of the various aetiologies were ascertained, and the outcome after treatment was recorded to assess the efficacy of the treatment methods being used. RESULTS: The most common cause of lack of eruption was the presence of supernumerary teeth (47% of patients). The other 53% of cases were distributed more or less equally between the remaining aetiological factors, which were odontomes (9%), dilacerations (9%), tooth germ malposition (12%), crowding (4%), one case of a calcifying odontogenic cyst (2%) and one case of trauma to the preceding deciduous tooth (2%). The aetiology of 15% of cases could not be ascertained. Once supernumerary teeth were removed, maxillary incisors usually erupted successfully with the help of conventional treatment methods such as surgical exposure and orthodontics. A relatively large number of incisors that failed to erupt due to other aetiological factors had to be extracted. CONCLUSIONS: Maxillary incisors that fail to erupt due to the presence of supernumerary teeth have a better prognosis than unerupted incisors with less common aetiologies.

Adolescent↗

Aesthetic effect of minor changes in incisor angulation: an internet evaluation.

The aim of this study was to evaluate the aesthetic assessment of different tiltings of the upper incisors with surrounding tissues. A picture of a smiling mouth revealing the upper anterior teeth from 15 to 25 was digitally transformed producing different tiltings of the incisors. These seven versions presented in a web-based survey were evaluated concerning their attractiveness. Overall 439 judges joined the evaluation. However, 249 judges were included in analysis, because only judges with normal wellbeings and completed questionnaires were accepted. These judges consisted of 38 dentists, 26 dental and 24 other students, 45 academics and 89 non-academics, while 27 gave no data about their profession. The results [median (first; third quartile)] showed significant that symmetrical incisors [67.5 (47.5; 85.0)] and minor changes in the angulation of one [65.0 (42.5; 80.0)] or both lateral incisors [65.0 (42.5; 80.0)], respectively, are aesthetically more attractive than the angulation of one [45.0 (27.5; 62.5)] or both central incisors [27.5 (16.3; 45.0)], or the combination of one tilted lateral and central incisor [37.5 (25.0; 60.0)]. These results confirm the results of a previous study where similar image versions without surrounding tissues were assessed concerning their attractiveness on printed photos.

Beauty↗

Subjective and objective perception of upper incisors.

The purpose of this study was to evaluate the subjective judgment (SJ) of patients on their own dental appearance and to correlate the results with objective measurements (OM) of their dentition concerning the appearance of the upper incisors. Seventy-five participants (30 men and 45 women) with normal well-being were included in the study. In a questionnaire they judged the appearance of their upper incisors. Furthermore, OM were evaluated by the investigator with regard to the following points: (i) absolute length of the upper central incisors, (ii) their length exposed during laughing, (iii) width-to-length ratio of central incisors and (iv) the proportion between the width of the lateral and central incisors. The subjective results were registered on visual-analogue scales. For the objective results standardized photographs were taken. No gender dependent differences could be found for the objectively measured parameters (median): OM1, 10.7 mm; OM2, 8.1 mm; OM3, 0.81; OM4, 0.79. However, significant correlations between subjective and objective results (SJ1/OM1, SJ2/OM2, SJ3/OM3) could be shown for men, but not for women. The maximum of the calculated regression-curves for men reflect 'golden standard values' well known from the literature. The degree of satisfaction concerning appearance of anterior incisors in accordance with golden standard values is higher for men than for women.

Adult↗

Effects of serum phosphate level on formation of incisor dentine in hypophosphatemic mice.

The effects of serum phosphate level on the formation of incisor dentine were investigated in hypophosphatemic (Hyp) mice fed a diet high in calcium and phosphorus (high Ca/P diet). Feeding a high Ca/P diet for more than 10 days resulted in an increase in the serum phosphate level in Hyp mice to one similar to that of normal mice. Lower incisors were cut transversely at the centre of the length of the incisor, a point that had taken approximately 40 days to be reached from the start of dentine formation in Hyp mice. Transverse views of the incisors showed a triangle-like outline in Hyp mice fed a control diet, while the outline became rounded in Hyp mice fed the high Ca/P diet for more than 40 days. In Hyp mice fed the high Ca/P diet for 40 days interglobular dentine was still observed and fluorescent lines produced by tetracycline showed a diffuse and wavy pattern in incisor dentine; however, interglobular dentine became indistinct and fluorescent lines showed a relatively smooth pattern in the incisor dentine of Hyp mice fed the diet for more than 60 days.

Animals↗

Maxillary incisor root resorption after rapid palatal expansion in Felis catus.

Root resorption after rapid palatal expansion (RPE) treatment was found in anchored teeth but has not been studied on non-anchored incisors. This study evaluated root resorption, root tipping, and root proximity of maxillary incisors after RPE treatment. Fourteen cats were divided into treated (n = 10) and untreated (n = 4) groups. The RPE treatment consisted of active, retention, and relapse phases, lasting 25, 60 and 60 d, respectively. Standardized occlusal radiographs were taken to measure tipping and root proximity before and after each treatment phase. Maxillary incisors were analysed histologically by fluorescent microscopy for root resorption. Data was analysed statistically with anova with repeated measures, t-test and Pearson's coefficient of correlation. Root resorption was confined to the first incisors and was 750-fold greater in the treated vs. the control group. Root tipping and root proximity were significantly greater (2.5- and 17-fold, respectively) in the first than in the second maxillary incisor and highly correlated with root resorption (r = -0.927 and 0.723, respectively). This suggests a cause (tipping and root proximity) and effect (root resorption) relationship. Data suggest that first maxillary incisor susceptibility to root resorption during RPE is associated with severe tipping and root proximity.

Animals↗

The association between incisor trauma and occlusal characteristics in individuals 8-50 years of age.

To explore the association between incisal trauma and occlusal characteristics using oral examination and health interview data from the Third National Health and Nutrition Examination Survey 1988-1994 (NHANES III). Incisal trauma examinations were performed on 15 364 individuals 6-50 years of age using an ordinal scale developed by the National Institute of Dental and Craniofacial Research. Occlusal examinations were performed on 13 057 individuals 8-50 years of age. We fitted separate multivariate logistic regression models for maxillary and mandibular incisor trauma adjusting for socio-demographic variables (age, gender, race-ethnicity) and occlusal characteristics (overbite, overjet, open bite). 23.45% of all individuals evidenced trauma on at least one incisor, with trauma more than four times more prevalent on maxillary (22.59%) than on mandibular incisors (4.78%). Males (OR = 1.67) had greater odds of trauma than females; Whites (OR = 1.37) and non-Hispanic Blacks (OR = 1.37) had greater odds of trauma than Mexican-Americans. The odds of trauma increased with age, peaked from age 21 to 30 (OR = 2.92), and declined. As overjet increased, so did the odds of trauma. Compared to individuals with < or =0-mm overjet, odds of trauma increased from 1-3 mm (OR = 1.42) to 4-6 mm (OR = 2.42) to 7-8 mm (OR = 3.24) to >8 mm (OR = 12.47). Trauma to incisors is prevalent but mostly limited to enamel. Trauma to maxillary incisors is associated with overjet, gender, race-ethnicity, and age, while trauma to mandibular incisors is associated with gender, age, and overbite.

Adolescent↗

Effect of root canal infection and treatment of traumatized primary incisors on their permanent successors.

The purpose of the present retrospective study was to evaluate the effect of trauma, root canal infection and treatment of non-vital primary incisors on their permanent successors. A total of 117 permanent central incisors were examined clinically and radiographically for the presence of discolorations, hypoplasia, or disturbances in root development. Of these, 29 were succedaneous to traumatized, endodontically involved and treated primary incisors (Group A). Another 29 had their traumatized, endodontically involved, primary predecessors extracted or left untreated (Group B). The remaining 59 incisors were intact and had no history of trauma (Group C). Severe hypoplasia could not be observed in any of the teeth, and no disturbances in root development could be disclosed radiographically. The incidence of defects in Groups B and C was similar, whereas in Group A it was 2 or 3 times higher than in each of the other two groups. Despite this fact, root canal treatment of traumatized non-vital primary incisors should be considered a treatment option, as premature extraction of a primary incisor may lead to speech problems, premature eruption and/or malalignment of the permanent successor, or affect the child's self image.

Chi-Square Distribution↗

Survival of avulsed permanent maxillary incisors in children following delayed replantation.

The purpose of this study was to identify the variables that significantly influenced the survival of incisors replanted after extended extra-alveolar duration at The Hospital for Sick Children, Toronto, Canada, between June 1988 and December 1993. Survival analysis was used to identify variables that significantly influence the retention of replanted incisor teeth. Survival was defined as the time that elapsed between the replantation of an avulsed incisor and the time it was finally lost. Information on 9 variables was collected for 38 patients (25 males; 13 females) and 52 replanted permanent maxillary incisors. The mean extra-alveolar duration for the sample was 123 min. The mean follow-up interval was 942 days (range: 364-2126 days). Incisors replanted with open apices had a significantly decreased survival compared with teeth with mature apices (P = 0.04; relative risk 4.2). There was also a significant association between increased survival and obturation of the root canal with gutta-percha and sealer (P = 0.006; relative risk 10.0). A trend towards improved survival of replanted incisors was found for children older than 11 years old at the time of replantation (P = 0.09; relative risk 2.8). These results are consistent with previous studies and may assist clinicians and parents in the decision-making process associated with the management of avulsed teeth in children.

Child↗

Development of clinical and radiographic signs associated with dark discolored primary incisors following traumatic injuries: a prospective controlled study.

The purpose was to evaluate late complications of asymptomatic traumatized primary incisors with dark coronal discoloration. The clinical and radiographic signs of 97 teeth of the study group were recorded along a follow-up period that ranged between 12 and 75 months (mean >36 months). Children's age at time of injury ranged between 18 and 72 months (mean 40). The control group consisted of 102 non-discolored maxillary primary central incisors in 51 children older than 54 months with no history of dental trauma. In 50 teeth (52%) the color faded or became yellowish and in 47 (48%) it remained dark. Clinical signs of infection, that were diagnosed 5-58 months after the injury, were associated significantly more with dark than yellowish hues (83 and 17%, respectively). Teeth that had changed their color to become yellow presented more PCO than teeth with black/gray/brown coronal discoloration (78 and 6%, respectively). Arrest of dentine apposition was found in 15 teeth, one had yellow coronal discoloration and the remaining 14 had a dark shade. Eleven teeth showed inflammatory root resorption all with dark discoloration. Two atypical types of root resorption were observed: a surface resorption restricted to the lateral aspects of the apical half of the root while the root length remained unchanged and in the other expansion of the follicle of the permanent successor was observed. Expansion of the dental follicle was observed in 72% of all teeth with no significant difference between the various types of coronal discoloration but only half of the cases were associated with resorption of the root of the primary incisor. The various pathologic findings observed in the study group were either absent or rarely seen in the control group. It can be concluded that more than 50% of the primary incisors that retain their dark coronal discoloration acquired after dental injuries remain clinically asymptomatic till the eruption of the permanent successor even if they present accelerated root resorption. Asymptomatic traumatized primary incisors that retain their dark coronal discoloration may develop a sinus tract and inflammatory root resorption years after the injury. There is still a dilemma: which treatment is better for dark discolored primary incisors: early endodontic treatment or follow-up with the risk of development of infection and root resorption that may require extraction?

Bacterial Infections↗

Central incisor width as a predictor of appropriate curette size in adenoidectomy.

As inadvertent eustachian tube injury during adenoidectomy can have serious short- and long-term implications, a simple anatomic correlate that could predict the optimal curette choice for adenoidectomy, especially in severely hypertrophic cases, is beneficial. This study evaluates the correlation of the distance between the lateral borders of the upper central incisors and the distance between the tori tubarius in the nasopharynx. One hundred one consecutive patients undergoing adenoidectomy at a pediatric tertiary care hospital were enrolled in this study. The patients ranged in age from 7 months to 15 years. No complications were noted in any of the procedures. During the operation, the distance between the central upper incisors was measured in millimeters, as was the inter-tubarius width (ITW). A multiple regression analysis was completed to assess the correlation between central incisor width and ITW. Age and inter-incisor width were positively correlated with ITW in a statistically significant manner (p = .007 and p = .006, respectively). The distance between the lateral borders of the upper central incisors predicts the distance between the tori tubarius in the nasopharynx. Therefore, an adenoid curette the window of which does not overlap the lateral aspects of the central upper incisors can be used relatively safely, even in fields with poor visualization.

Adenoidectomy↗

Prenatal development of the alveolar bone of human deciduous incisors and canines.

The formation of the human alveolar process around the incisors and canines is a hitherto unreported aspect of fetal oral development. The question is how, where, and when the alveolar process is formed. The purpose of this study was to elucidate the questions where and when and hence to analyze the pattern of formation of the alveolar bone around developing human deciduous canine and incisor teeth. The study was conducted with material selected from a sample of 61 normal human fetuses, legally or spontaneously aborted. Fertilization ages ranged from 9 to 22 weeks, crown-rump Length from 25 to 205 mm, and foot length from 4 to 34 mm. From this material, 7 maxillae and 10 mandibles were selected for the study according to developmental stages of the canines and incisors and according to the orientation of the histological sections. The skeletal investigation consisted of macroscopic and microscopic analysis of the mandibles and maxillae. The investigations revealed the absence of bone between the central and lateral incisors in the mandibles and maxillae of fetuses below the ages of 21 and 22 weeks, respectively. In three specimens, alveolar bone between the central and lateral incisors was recorded (21, 21, and 22 weeks of fertilization). Absence of bone labial to the canine was recorded in all fetuses investigated. In all other regions, alveolar bone occurred as a regular finding. The present study has shown that alveolar bone formation is strictly coordinated with tooth formation. Alveolar bone occurs later in the area labial to the canine and in the region between the central and lateral incisors than it does in other areas associated with the incisor/canine regions. Knowledge of this pattern in the formation of the alveolar process seems to be of importance for a future elucidation of how the alveolar process is initially formed.

Alveolar Process↗

Review article. The rat incisor in toxicologic pathology.

Microscopic examination of the incisors of rats and mice may reveal toxicologically significant changes. First, the incisor morphology reflects the nutritional status of the animal: fluctuations of mineral metabolism and vitamin availability are disclosed by the rodent incisors, because the incisors continue to grow during life. Similarly, direct or indirect changes of mineral metabolism by a test substance are reflected in the morphological appearance of the incisor dentin. In addition, hormonal disturbances may give rise to typical structural alterations of the incisor in the test animal. Certain chemicals may have deleterious effects upon the odontogenic tissues, resulting in tooth malformation and malocclusion and eventually in odontomas. Apparent nasal tumors may turn out to be of dental origin. Nasal luminal masses that are discussed within this scope are dental malformation, dental callus, and true odontogenic tumors. According to our experience, odontogenic tumors might possibly develop within the scope of a reaction to mechanical tooth trauma as well. In carcinogenicity studies, this consideration deserves attention when evaluating treatment-related putative odontogenic tumors.

Animals↗

A comparison of two- and three-dimensional incisor angles.

Two- and three-dimensional incisor angulations are compared in 40 patients using lateral radiographs and direct dental cast measurement using the Reflex Metrograph coupled to a computer. The two-dimensional upper and lower incisor angulations to the occlusal plane were also compared by the two methods. It was found that: The two-dimensional radiographic and three-dimensional dental cast inter-incisor angulation showed a significant difference at a probability level 0.01 greater than p greater than 0.001. The two-dimensional radiographic and two-dimensional dental cast upper left and right incisor angulations to the functional occlusal plane showed a significant difference at a probability level of 0.01 greater than p greater than 0.001. The significant differences can be attributed to the measurement of the incisor crown angulation in the dental cast measurement and the incisor tip and apex assessment in the radiographic technique. The system of dental cast measurement arguably provides a more realistic and reliable assessment of incisal angles than conventional radiographic measurement techniques.

Cephalometry↗

Post-retention crowding and incisor irregularity: a long-term follow-up evaluation of stability and relapse.

The aim of the present long-term follow-up study of orthodontically-treated patients (mean: 15.7 years) was to analyse post-retention changes and to reveal factors which may play a role as predictors for long-term prognosis. Pretreatment, end-of-treatment, and post-retention models of 226 cases with all types of anomaly were used to measure intercanine and intermolar width, arch length, and sum of the mesiodistal dimension of the incisors, Irregularity Index, crowding, molar and canine relationship, overjet, and overbite. In order to assess the influence of sex, initial and end-of-treatment alignment, type of therapy, amount of tooth movement, and presence of third molars on the extent of post-retention changes, the total sample was divided into subgroups. Findings indicated that post-retention crowding and incisor irregularity increased more frequently in the mandible than in the maxilla. Pretreatment variables such as increased mesiodistal incisor dimension, severe crowding and incisor irregularity, arch length deficiency, arch constriction, and increased overbite as well as post-treatment spacing, arch expansion, increased arch length, and residual Class II or III molar relationships were found to be associated factors in the process of post-retention increase of crowding and incisor irregularity. 'Overexpansion' was found to be a factor in mandibular incisor relapse.

Analysis of Variance↗

Surgical repositioning of an impacted dilacerated incisor in mixed dentition.

BACKGROUND: Treatment options for a dilacerated incisor are either extraction or surgery and orthodontic traction. Because patients with such incisors usually are young, and because of the root angulation of the impacted incisor, treatment usually is lengthy and complicated. Surgical repositioning provides another option for treatment of this unique problem. CASE DESCRIPTION: The author presents the case of a 9-year-old girl with an impacted dilacerated maxillary central incisor to demonstrate the timing, technique and results of the surgical repositioning treatment approach. The advantages of this approach include immediate esthetic improvement, use of a single and simplified surgical procedure, simple and short orthodontic therapy, a normal gingival margin and the possibility of the developing root's adapting to the new position. CLINICAL IMPLICATIONS: Surgical repositioning is a simplified treatment for dilacerated incisors. It is especially valuable in cases of difficult-to-treat impaction. Timing of surgical repositioning depends on the incisor's root development and the space available for the transplant.

Child↗

Maxillary lateral incisors of subjects with cleft lip and/or palate: Part 2.

Maxillary lateral incisors on the alveolar cleft were investigated in 431 cleft children registered in the Department of Orthodontics, Kyushu University Dental Hospital. The majority of primary maxillary lateral incisors were located on the distal side of the alveolar cleft in both unilateral cleft lip and alveolus (UCLA) and unilateral cleft lip and palate (UCLP) subjects. Permanent teeth in UCLA tend to be located distally, but in UCLP they tend to be congenitally absent (p less than .01). The majority of primary teeth had normal shapes; the majority of permanent teeth were of intermediate type or were missing congenitally. One third of the UCLA and one half of the UCLP subjects who had primary maxillary lateral incisors were not followed by permanent replacements. The location of the majority of permanent maxillary lateral incisors tallied with that of the primary ones except in four UCLA, ten UCLP, and two bilateral cleft lip and palate (BCLP) subjects. Four UCLA and ten UCLP subjects who had primary lateral incisors on the distal side were followed by their permanent successors on the mesial side. Three UCLP and one BCLP subjects had permanent maxillary lateral incisors even though they had no temporary predecessors.

Adolescent↗

The relation between tooth shape ratio and incisor arrangement in Japanese children.

To investigate whether the relationship between tooth shape ratio and incisor arrangement proposed by Peck et al. in 1972 was applicable to Japanese children, we compared two groups, one with normal permanent dentition and another with crowded permanent dentition, using chronologically constructed plaster dentition models. Tooth shape ratio was obtained by dividing the incisor mesio-distal width by the labio-lingual width and then multiplying the result by 100. The results revealed a significant difference in the coronal mesio-distal diameter of the incisors between the two groups, but the other items showed no significant differences, suggesting no clear relationship between tooth shape ratio and incisor arrangement. That was, our results suggest that there is no clear relationship between tooth shape ratio of the mandibular incisors and arrangement of the permanent incisors in Japanese children.

Adolescent↗