SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Late lower incisor crowding and incisor rotations remain a problem in orthodontics. We describe a new fixed retainer which is simple to use, allows physiological tooth movement, but prevents rotational and labio-lingual relapse.
Fifty consecutive cases presenting with unerupted maxillary incisors at orthodontic clinics were recorded and progress of the unerupted tooth followed up over a 4-year period following the exposure of the unerupted tooth (including removal of supernumerary tooth, etc., if present). The occlusal level, rotation, tilting, and general appearance were assessed at the conclusion of the investigation and the results are presented in this report. The earlier the removal of the causative factor preventing eruption of the incisor the better is the prognosis, and it is suggested that all teeth that have not erupted 6 months after the normal eruption date should be subject to radiological examination to ascertain any possible cause for the delayed eruption.
Solitary median maxillary central incisor syndrome (SMMCI) is a complex disorder consisting of multiple, mainly midline defects of development resulting from unknown factor(s) operating in utero about the 35th-38th day(s) from conception. It is estimated to occur in 1:50,000 live births. Aetiology is uncertain. Missense mutation in the SHH gene (I111F) at 7q36 may be associated with SMMCI. The SMMCI tooth differs from the normal central incisor, in that the crown form is symmetric; it develops and erupts precisely in the midline of the maxillary dental arch in both primary and permanent dentitions. Congenital nasal malformation (choanal atresia, midnasal stenosis or congenital pyriform aperture stenosis) is positively associated with SMMCI. The presence of an SMMCI tooth can predict associated anomalies and in particular the serious anomaly holoprosencephaly. Common congenital anomalies associated with SMMCI are: severe to mild intellectual disability, congenital heart disease, cleft lip and/or palate and less frequently, microcephaly, hypopituitarism, hypotelorism, convergent strabismus, oesophageal and duodenal atresia, cervical hemivertebrae, cervical dermoid, hypothyroidism, scoliosis, absent kidney, micropenis and ambiguous genitalia. Short stature is present in half the children. Diagnosis should be made by eight months of age, but can be made at birth and even prenatally at 18-22 weeks from the routine mid-trimester ultrasound scan. Management depends upon the individual anomalies present. Choanal stenosis requires emergency surgical treatment. Short stature may require growth hormone therapy. SMMCI tooth itself is mainly an aesthetic problem, which is ideally managed by combined orthodontic, prosthodontic and oral surgical treatment; alternatively, it can be left untreated.
In this paper orthodontic treatment involving extraction of a lower incisor is described. This has traditionally been regarded as a compromise as loss of a lower incisor renders it impossible to achieve true ideal occlusion. However, with careful case selection, treatment planning and visualization of the post-treatment occlusion, excellent functional and aesthetic results can be achieved. The various factors that govern the decision to treat certain malocclusions in this way are discussed and a clinical case is presented to demonstrate this type of treatment.
Trauma to the permanent dentition, particularly the maxillary incisors, is common. Prompt and appropriate management can significantly improve the prognosis for many of these dentoalveolar injuries. Unfortunately, much of this trauma is left untreated. This paper discusses the management of children who present with intruded permanent incisors.
In this paper, the current knowledge about Molar Incisor Hypomineralization (MIH) is presented. MIH is defined as hypomineralization of systemic origin of one to four permanent first molars frequently associated with affected incisors and these molars are related to major clinical problems in severe cases. At the moment, only limited data are available to describe the magnitude of the phenomenon. The prevalence of MIH in the different studies ranges from 3.6-25% and seems to differ in certain regions and birth cohorts. Several aetiological factors (for example, frequent childhood diseases) are mentioned as the cause of the defect. Children at risk should be monitored very carefully during the period of eruption of their first permanent molars. Treatment planning should consider the long-term prognosis of these teeth.
Developmentally absent permanent maxillary lateral incisors may be associated with several problems. The decision whether to open or to close the space should involve the patient/parent, orthodontist and restorative dentist. To optimize function and aesthetics, space should be opened using fixed appliances to accommodate an appropriate prosthesis. Implant-retained crowns offer several advantages, although adhesive bridges are more appropriate in certain circumstances. Removable partial dentures may be necessary in some instances. Where space opening is not feasible, practical or desirable, any residual spacing can be closed using fixed appliances and the permanent maxillary canines modified to resemble lateral incisors.
Radicular cysts associated with the deciduous dentition are rare. The literature is sparse regarding cysts associated with primary incisor teeth, which is surprising given the frequency with which these teeth are traumatized. Most cases reported involve molar teeth associated with apical infection following on from caries. A case of a 3-year-old boy who developed a large radicular cyst associated with a previously traumatized upper primary incisor is reported.
Toothwear cases can vary dramatically in their presentation, with some displaying quite peculiar patterns. This case report outlines a patient's unusual eating habit that had led to a localized pattern of toothwear affecting his maxillary and mandibular central incisors. The patient had a habit of eating fresh chillies between his incisors after most evening meals; this was followed by immediate toothbrushing, which he had done for many years. This case illustrates that, not only is diet analysis important in identifying aetiological factors in toothwear cases, but also dietary habits.
We examined the effects of fructooligosaccharides (FOS) on the reduction in the incisor iron content in gastrectomized rat. Twenty-eight 5- wk-old male Sprague-Dawley rats were divided into two groups: sham operated (bSH) and gastrectomized (bGX). After 4 wk, each group was divided into two subgroups according to the presence or absence of 7.5% FOS in the synthetic diet (SH, SH+FOS, GX, and GX+FOS). At 10 wk after surgery, the maxilla was prepared to examine the iron content of the incisor enamel surface at four points. These points corresponded to the iron content at 6, 7, 8, and 10 wk, respectively. Blood was collected to determine serum iron levels at 4 and 10 wk. The serum iron level significantly decreased at 4 and 10 wk in the GX group. At 10 wk, the level in the GX+FOS group significantly increased but did not reach that in the SH group. The iron content of the enamel surface time-dependently increased and no significant differences were seen between SH and GX+FOS at 8 and 10 wk. These results suggest that FOS consumption impaired the loss of enamel content following gastrectomy, and this effect preceded the effect on the serum iron level.
A 3-year-old girl had a darkened and symptomatic maxillary right deciduous central incisor. This report describes the rationale and technique for a labial pulpectomy access opening and subsequent composite resin restoration. This innovative approach for the pulpal treatment of these deciduous incosors not only improves the access for instruments and direct visualization for the operator but also greatly improves the appearance of the dark teeth without complete coverage. Two other clinical applications of this labial approach should also be mentioned. First, anterior stainless steel crowns can be made esthetically pleasing by placing labial resin facings in the crown. Second, access for pulpotomy procedures can be improved with use of a labioincisal approach after the incisal reduction step in the preparation of deciduous incisors for complete coverage.
BACKGROUND: Laser Doppler flowmetry, or LDF, is a noninvasive method used to assess pulpal blood flow, or PBF. Dental avulsion is associated with loss of pulpal sensitivity. The authors conducted this study to assess whether LDF could be used to detect revascularization of replanted teeth. METHODS: The authors used LDF to assess the PBF values of avulsed permanent maxillary incisors treated using replantation and splinting in 17 subjects. They took measurements at four sessions: on the day of splint removal and at 12 weeks, 24 weeks and 36 weeks after splint removal. Five vital control teeth and five nonvital control teeth were used to assess the background signal. At 36 weeks, the authors determined clinically and radiographically whether revascularization had occurred. RESULTS: LDF readings correctly predicted the pulp status in 88.2 percent of the readings. Of the readings for vital teeth, 100 percent were correct, and of the readings for nonvital teeth, 80 percent were correct. Univariate analysis of variance demonstrated that in revascularized teeth, the PBF value increased significantly from splint removal to week 12 after splint removal and from week 24 to week 36 after splint removal. In the teeth that failed to revascularize, the PBF value dropped significantly from week 24 to week 36 after splint removal. CONCLUSIONS: The results of this study suggest that LDF accurately diagnoses revascularization of avulsed maxillary incisors after replantation and splinting. CLINICAL IMPLICATIONS: LDF may become useful in detecting revascularization much earlier than standard sensitivity tests.
The use of post and core systems has become an excellent alternative for restoring endodontically treated teeth. The aim of this study was to evaluate the von Mises, maximal compressive and tensile stresses distribution using the Finite Element Method (FEM) on human teeth restored with different post and core systems. The analysis was made on endodontically treated maxillary central incisors. The post systems used in this investigation were the stainless steel or titanium Flexi Post/Flexi Flange. Composite resin was used as core material and resin cement was the cement material of choice to seat a full porcelain crown. The bi-dimensional mathematical model was created from pictures taken from an intact human maxillary central incisor and prefabricated posts. This image was transferred to a personal computer in the MSC/Nastran 4.5 software. A static and linear analysis treatment was performed when a 45 load of 100 N was applied on the lingual surface of the tooth. Based on the results obtained, it can be concluded that the post design and its material can alter the stress pattern distribution.
As a pilot study, dental casts of 30 patients with unilateral cleft lip and palate were selected and examined from the longitudinal data in the Department of Orthodontics, Kyushu University Dental Hospital. Dental casts of the anterior teeth were sectioned at right angles to the long axis of the tooth 2 to 3 mm below the incisal edge. The teeth were differentiated according to their cross sections. They were classed as lateral incisors or other types by the ratio of labiolingual diameter to mesiodistal diameter and the flatness labiolingually. Dental casts of 309 additional patients with cleft alveolus were examined subjectively based on above findings. In primary dentition, 183 of 184 teeth on the cleft side were incisal type. One tooth was canine type. In permanent dentition, 42 of 78 teeth on the cleft side were conical type, 20 teeth were intermediate type, and 16 teeth were incisal type. As a conclusion, the tooth on the cleft side is almost certain to be a lateral incisor, not a supernumerary canine tooth. As well, their form was normal in the majority of the primary dentition, but malformed in the permanent one.
OBJECTIVE: To examine the changes in jaw movement and temporalis muscle activity of a patient with unilateral cleft lip and palate before and after edgewise treatment. DESIGN: Clinical case study. SETTING: University dental hospital, department of orthodontics. PATIENT: A 12-year 3-month-old male with incisor crossbite, molar malocclusion, and repaired unilateral cleft lip and palate who had completed first-phase orthodontic treatment. MAIN OUTCOME MEASURES: This patient was treated with an edgewise appliance. Jaw movement and temporalis muscle activity during the chewing of a hard gummy jelly were recorded at 2 kHz from the sixth to the twentieth stroke before edgewise treatment and after a retention period of 2 years. RESULTS: Optimum intercuspation of teeth was achieved. The reversed crossing jaw-movement pattern before treatment changed to a normal grinding after treatment. The posterior temporalis muscle on the chewing side exhibited an earlier burst than the contralateral one during chewing at the post-treatment stage, as is observed in cases with good occlusion. CONCLUSION: Improvement in the occlusion using an edgewise appliance is necessary for acquiring a good masticatory function in patients with incisor crossbite, molar malocclusion, and cleft lip and palate.
The postnatal development of innervation in the lingual periodontal ligament of rat incisors was investigated by immunohistochemistry using an antibody against protein gene product 9.5 (PGP 9.5), a neuron-specific protein. Immunostaining with the antibody enabled the clear demonstration of chronological alteration in the distribution and maturation of nerve terminals after birth. At 1 day after birth, thick nerve fibers showing PGP 9.5-immunoreactivity first appeared in the loose connective tissue corresponding to the future periodontal ligament, without forming an apparent terminal structure. At 4 days, two portions became distinguishable in the lingual periodontal ligament: alveolus- and tooth-related parts being comparable to those in the adult ligament. The immunoreactive nerve fibers increased in density and appeared to extend more incisally. Those restricted to the alveolus-related part showed ramifications with a small number of expanded or bulbous portions, and terminated among the periodontal fibers. Characteristic dendritic and expanded terminals, similar to Ruffini endings in the adult ligaments, began to occur in the lingual periodontal ligament at 7 days after birth and gradually increased in number until day 11 when the incisal edges emerged in the oral cavity. At approximately 15 days after birth, nerve endings possessing morphological features similar to Ruffini endings in adult rats were recognizable in the entire length of the periodontal ligament. After the eruption of first molars, the periodontal Ruffini endings drastically increased in number, and by the time the occlusion between the first molars was established, became identical in distribution and density to those seen in the lingual periodontal ligament of adult rat incisors. These findings suggest that the mechanical stimuli due to tooth eruption and occlusion might be a prerequisite for the final differentiation and maturation of the periodontal Ruffini endings.
Vascular architecture in the periodontal ligament of hamster incisors was investigated by use of vascular casts under a scanning electron microscope (SEM). In addition to ordinary nutrient blood vessels, anastomosing vessels of large caliber developed, surrounding the incisor. From their characteristic configuration, these vessels were regarded as "sinusoids". The plexus of sinusoidal vessels was connected with capillaries in the papillary layer of the enamel organ at the labial periodontal ligament, and with veins penetrating into the alveolar bone on the lingual side. Transmission electron microscopic (TEM) observation showed that the sinusoidal wall was composed of only a thin layer of endothelial cells, lacking a smooth muscular element, and surrounded by densely arranged collagen fibers. Although the frequent association of Ruffini-type nerve endings with sinusoidal vessels was noted, neither direct contact nor specialized structures between these was recognizable. A possible function of the periodontal sinusoids is discussed on the basis of their distribution and ultrastructural evidence.
The inhibitory effect of the continual administration of 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) (8 mgP/kg/day) through a mini osmotic pump on dentin mineralization was examined in relation to the diurnal rhythm of the rat and compared with that of daily injections of same amounts of HEBP known to inhibit dentin mineralization. After daily injections of HEBP, a series of alternating rows of mineralized and non-mineralized dentin islands appeared in the newly formed portion of the crown-analogue of rat incisors. A similar phenomenon occurred under the continual administration of HEBP in rats raised either under regular environmental photofraction or constant lighting conditions. The average distance between the adjacent mineralized dentin islands was 521.0 +/- 51.3 microns in the injected rats. After continual HEBP administration, this was 426.0 +/- 13.2 microns and 416.5 +/- 19.4 microns under ordinary photofraction and constant light, respectively. Although the pattern of individual mineralized dentin islands tended to become irregular in nocturnal rats, no statistical difference was noted between the two values. Rows of mineralized and non-mineralized dentin islands also appeared in the root analogue dentin. No sign of the intermittent inhibition of mineralization was recognized in mesodermal hard tissues other than dentin in the HEBP-affected animals. These data implicate the presence of intrinsic cycles in dentin mineralization at the growing end of rat incisors independent of environmental photofraction as well as the ameloblast function.