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Journal (Canadian Dental Association) Jun 2003Mesiodentes are the most common supernumerary teeth, occurring in 0.15% to 1.9% of the population. Given this high frequency, the general dentist should be knowledgeable... (Review)
Review
Mesiodentes are the most common supernumerary teeth, occurring in 0.15% to 1.9% of the population. Given this high frequency, the general dentist should be knowledgeable about the signs and symptoms of mesiodentes and appropriate treatment. The cause of mesiodentes is not fully understood, although proliferation of the dental lamina and genetic factors have been implicated. Mesiodentes can cause delayed or ectopic eruption of the permanent incisors, which can further alter occlusion and appearance. It is therefore important for the clinician to diagnose a mesiodens early in development to allow for optimal yet minimal treatment. Treatment options may include surgical extraction of the mesiodens. If the permanent teeth do not erupt in a reasonable period after the extraction, surgical exposure and orthodontic treatment may be required to ensure eruption and proper alignment of the teeth. In some instances, fixed orthodontic therapy is also required to create sufficient arch space before eruption and alignment of the incisor(s). Early diagnosis allows the most appropriate treatment, often reducing the extent of surgery, orthodontic treatment and possible complications. This paper outlines the causes and modes of presentation of mesiodentes, and presents guidelines for diagnosis and management of nonsyndromic mesiodentes.
Topics: Humans; Incisor; Malocclusion; Maxilla; Orthodontics, Corrective; Tooth Eruption; Tooth, Impacted; Tooth, Supernumerary
PubMed: 12787472
DOI: No ID Found -
Dental Press Journal of Orthodontics 2022There are different possibilities of orthodontic planning for cases with congenital absence of maxillary lateral incisors. This subject divides the opinion of...
INTRODUCTION
There are different possibilities of orthodontic planning for cases with congenital absence of maxillary lateral incisors. This subject divides the opinion of orthodontists and oral rehabilitation clinicians, due to the advantages and disadvantages of each treatment option, which may involve opening spaces for future implants and/or prosthetic restorations, or closing the spaces by positioning the maxillary canines in the place of lateral incisors. The correct diagnosis and careful evaluation of each patient allow to determine the best therapeutic approach. This paper discusses the main topics to be considered when planning these cases.
OBJECTIVES
To evaluate the main aspects related to orthodontic treatment planning in cases of congenital absence of maxillary lateral incisors, to aid the decision-making, with clinical and scientific basis.
Topics: Anodontia; Cuspid; Esthetics, Dental; Humans; Incisor; Malocclusion; Maxilla
PubMed: 35674572
DOI: 10.1590/2177-6709.27.1.e22spe1 -
Clinical Oral Investigations Sep 2009Root resorption of maxillary lateral incisors caused by erupting canines is well known and a relatively common phenomenon. However, much debate and conflicting evidence... (Review)
Review
Root resorption of maxillary lateral incisors caused by erupting canines is well known and a relatively common phenomenon. However, much debate and conflicting evidence exists with regard to the actual resorption trigger and potential etiological factors involved. Consequently, there are no obvious clinical clues concerning prevention and diagnosis as well as subsequent treatment decisions. The introduction of cone beam computer tomography has recently allowed drawing a new and much more documented light on the diagnostic and therapeutic strategies. However, no investigations have determined that this new information may result in another and better diagnostic approach and an improved treatment outcome. Therefore, the present review will attempt to summarize the existing evidence on two- and three-dimensional images and try to link the radiological observations to any further preventive, diagnostic, and/or therapeutic measures. Detection thresholds, accuracy, and reliability of impacted canine localization and neighboring root resorption risks will also be considered. This review demonstrates how adding a third-dimension to the radiographic information may notably alter the prevalence of root resorptions and descriptions of this prevalence. In any case, further investigation is needed to determine resorption detection thresholds in various two-dimensional and three-dimensional imaging techniques, as well as to determine therapeutic thresholds and criteria for strategic tooth extraction based on radiographic manifest and not manageable resorption lesions.
Topics: Cone-Beam Computed Tomography; Cuspid; Dental Sac; Humans; Imaging, Three-Dimensional; Incisor; Maxilla; Orthodontics, Corrective; Root Resorption; Tooth Eruption, Ectopic; Tooth, Impacted
PubMed: 19277728
DOI: 10.1007/s00784-009-0262-8 -
The Angle Orthodontist Nov 2021To analyze the biomechanical system of anterior retraction with clear aligner therapy (CAT) with and without an anterior mini-screw and elastics.
OBJECTIVES
To analyze the biomechanical system of anterior retraction with clear aligner therapy (CAT) with and without an anterior mini-screw and elastics.
MATERIALS AND METHODS
Models including a maxillary dentition (without first premolars), maxilla, periodontal ligaments (PDLs), attachments, and aligners were constructed and imported to finite element software. Three model groups were created: (1) control (CAT alone), (2) labial elastics (CAT with elastics between the anterior mini-screw and buttons on central incisors), and (3) linguoincisal elastics (CAT with elastics between the anterior mini-screw and precision cuts on the lingual sides of the aligner). Elastic forces (0-300 g, in 50 g increments) were applied.
RESULTS
CAT alone caused lingual tipping and extrusion of the incisors. Labial elastics caused palatal root torquing and intrusion and mesial tipping of the central incisors, while linguoincisal elastics produced palatal root torquing and intrusion of both central and lateral incisors. Second premolars were intruded in all three groups, with less intrusion in the linguoincisal elastics group. For the control group, stress was concentrated on both labial and lingual root surfaces, alveolar ridge, and cervical and apical PDLs. Stress was more concentrated in the labial elastics group and less concentrated in the linguoincisal elastics group.
CONCLUSIONS
CAT produced lingual tipping and extrusion of incisors during anterior retraction. Anterior mini-screws and elastics can achieve incisor intrusion and palatal root torquing. Linguoincisal elastics are superior to labial elastics with a lower likelihood of buccal open bite. Root resorption and alveolar defects may occur in CAT, more likely for labial elastics and less likely for linguoincisal elastics.
Topics: Bone Screws; Incisor; Orthodontic Appliances, Removable; Tooth Movement Techniques; Torque
PubMed: 34061964
DOI: 10.2319/120420-982.1 -
The Angle Orthodontist Jan 2022To evaluate incisor position and its relationship to alveolar bone in untreated optimal occlusions and in untreated Class II malocclusions.
OBJECTIVES
To evaluate incisor position and its relationship to alveolar bone in untreated optimal occlusions and in untreated Class II malocclusions.
MATERIALS AND METHODS
Fifty-seven lateral cephalograms of individuals with naturally occurring optimal occlusions (mean age = 23 years) were used to assess positions of central incisors and their relationships to alveolar bone. Data were compared to a sample of 57 individuals with untreated Class II malocclusions with concurrent anterior-posterior (AP) skeletal discrepancies (mean age = 16.9 years).
RESULTS
Significant intergroup differences were found for AP jaw relationship, maxillary alveolar bone thickness, mandibular incisor inclination, maxillary incisor root distance to labial surface of alveolar bone, and mandibular incisor root apex distance to labial surface of alveolar bone. Small differences between females and males existed for several variables. In both samples, maxillary incisor roots were located closer to the labial surface of alveolar process than to the palatal surface by roughly a 2:1 ratio. Mandibular incisor root apices were generally equidistant from the labial and lingual surfaces of the alveolus in the optimal sample but closer to the lingual surface in the Class II sample.
CONCLUSIONS
Maxillary incisors tend to occupy the anterior one-third of the alveolus in untreated individuals, regardless of AP interarch dental relationships or AP jaw relationships. Mandibular incisor root apices tend to be centered within the alveolus in untreated optimal occlusions but are more positively inclined, and their root apices are more posterior in untreated Class II malocclusions.
Topics: Adolescent; Adult; Alveolar Process; Cone-Beam Computed Tomography; Female; Humans; Incisor; Male; Mandible; Maxilla; Young Adult
PubMed: 34383019
DOI: 10.2319/022320-122.1 -
Journal of the Formosan Medical... Apr 2022Incisor liability is the discrepancy in the sum of the mesiodistal crown width between the primary and permanent incisors. Incisor liability affects the integrity and...
BACKGROUND/PURPOSE
Incisor liability is the discrepancy in the sum of the mesiodistal crown width between the primary and permanent incisors. Incisor liability affects the integrity and eruption of the permanent incisors during the transition from the primary to permanent dentition. This study investigated the incisor liability in the primary dentition of Taiwanese children.
METHODS
The digital periapical films of 203 upper arches of 105 boys and 98 girls and 195 lower arches of 119 boys and 76 girls aged between 3 and 6 years were selected in this retrospective study. The mesiodistal crown widths of the primary and permanent incisors were measured using the medical imaging software for both arches. Differences in incisor liability values were statistically analyzed.
RESULTS
The mean ± standard deviation of the incisor liability values were 8.32 ± 1.88 and 6.91 ± 1.13 mm for the upper and lower arches, respectively, in all children. The incisor liability was closely related with the total crown widths of the permanent incisors for upper and lower arches. The incisor liability values were higher among boys than girls for the upper but not lower arch.
CONCLUSION
Incisor liability differs depending on ethnicity. In Taiwanese children, incisor liability was closely related with the crown widths of the permanent incisors. The incisor liability values of boys were higher than those of girls in the upper arch but not the lower arch.
Topics: Asian People; Child; Child, Preschool; Female; Humans; Incisor; Male; Retrospective Studies; Tooth Eruption
PubMed: 34535377
DOI: 10.1016/j.jfma.2021.08.025 -
International Journal of Environmental... Nov 2022The tooth movement in the alveolus is possible due to bone remodeling. This process could be the risk factor for the formation of gingival recessions-the most common... (Review)
Review
The tooth movement in the alveolus is possible due to bone remodeling. This process could be the risk factor for the formation of gingival recessions-the most common side effects of orthodontic therapy. Gingival recessions are found 5.8-11.5% more frequently among the orthodontically treated patients. What is more, anterior mandibular teeth are the ones most prone to gingival recession dehiscences and fenestrations. The aim of this narrative review was to evaluate, based on CBCT (Cone beam computed tomography) scans, the changes in the alveolar bone of lower incisors in adolescent and adult patients after orthodontic tooth movements. From the pool of 108 publications, a total of 15 fulfilled the criteria of this review. Both retrospective and prospective longitudinal studies-using CBCT or CT (Computed Topography) and evaluating alveolar bone changes in mandibular incisors during orthodontic treatment performed before and after teeth movement-were included. In the group of growing patients, either proclination or retroclination of mandibular incisors led to increase of the distance from CEJ (cementoenamel junction) to marginal bone crest. The difference in bone loss was greater on the lingual side of the incisors in both types of tooth movement. The results were similar for adults patients. The thickness of the alveolar bone was reduced after proclination (total bone thickness) among growing and non-growing patients and retraction (lingual and buccal) of lower anterior teeth in the group of growing patients. The only improvement was measured for buccal thickness of mandibular incisor in bimaxillary protrusion patients treated with extraction therapy. The control of retraction movement (more root than crown movement) enhanced preservation on bone height and thickness. In order to minimize possible deterioration and place teeth in the center of alveolus, CBCT monitoring and scrupulous clinical evaluation are recommended.
Topics: Adolescent; Adult; Humans; Incisor; Gingival Recession; Retrospective Studies; Prospective Studies; Bone Remodeling
PubMed: 36429721
DOI: 10.3390/ijerph192215002 -
BMC Oral Health Dec 2022The aim of the study was to evaluate the cephalometric and dentoalveolar characteristics of maxillary lateral incisor agenesis patients, and to compare the findings to a...
BACKGROUND
The aim of the study was to evaluate the cephalometric and dentoalveolar characteristics of maxillary lateral incisor agenesis patients, and to compare the findings to a matched control group without tooth agenesis, excluding third molars, from the same population.
METHODS
The pre-orthodontic records of 72 non-growing patients, who were treated at the Orthodontic Department, Faculty of Dentistry, Alexandria University, were used to address the aim of this retrospective study. Patients having unilateral or bilateral maxillary lateral incisor agenesis, with no history of previous orthodontic treatment, congenital craniofacial malformations, facial trauma, or surgeries were divided into two test groups based on the pattern of maxillary lateral incisors agenesis (group I: unilateral (UMLIA), group II: bilateral (BMLIA)). A control group (group III (CTRL)) having a complete set of permanent dentition (excluding third molars), and having no dental anomalies was age-matched with the test groups. Measurements were performed on the pre-orthodontic lateral cephalometric radiographs and the pre-orthodontic digital dental casts. The measured variables were compared between the groups using one-way ANOVA and Kruskal Wallis tests according to the normality of the variable. In case of significant results, both tests were followed by multiple pairwise comparisons using Bonferroni adjusted significance level. Significance level was set at P < 0.05.
RESULTS
BMLIA group showed a smaller SNA angle and maxillary length, a more negative ANB angle and Wits appraisal, and a larger Maxillo-mandibular differential than UMLIA and/or CTRL group. The dental and soft tissue cephalometric measurements did not show any significant differences between the groups. Dentoalveolar cast measurements showed that BMLIA patients presented with significantly smaller maxillary inter-canine width than UMLIA and CTRL patients.
CONCLUSIONS
Cephalometric analysis has shown that subjects with BMLIA have a statistically significant reduced ANB and maxillary length. Tooth eruption may play a role in the development of the maxillary arch.
Topics: Humans; Incisor; Cross-Sectional Studies; Retrospective Studies; Anodontia; Cuspid; Maxilla
PubMed: 36522742
DOI: 10.1186/s12903-022-02656-7 -
Developmental Biology Apr 2021Mice possess two types of teeth that differ in their cusp patterns; incisors have one cusp and molars have multiple cusps. The patterning of these two types of teeth...
Mice possess two types of teeth that differ in their cusp patterns; incisors have one cusp and molars have multiple cusps. The patterning of these two types of teeth relies on fine-tuning of the reciprocal molecular signaling between dental epithelial and mesenchymal tissues during embryonic development. The AP-2 transcription factors, particularly Tfap2a and Tfap2b, are essential components of such epithelial-mesenchymal signaling interactions that coordinate craniofacial development in mice and other vertebrates, but little is known about their roles in the regulation of tooth development and shape. Here we demonstrate that incisors and molars differ in their temporal and spatial expression of Tfap2a and Tfap2b. At the bud stage, Tfap2a is expressed in both the epithelium and mesenchyme of the incisors and molars, but Tfap2b expression is restricted to the molar mesenchyme, only later appearing in the incisor epithelium. Tissue-specific deletions show that loss of the epithelial domain of Tfap2a and Tfap2b affects the number and spatial arrangement of the incisors, notably resulting in duplicated lower incisors. In contrast, deletion of these two genes in the mesenchymal domain has little effect on tooth development. Collectively these results implicate epithelial expression of Tfap2a and Tfap2b in regulating the extent of the dental lamina associated with patterning the incisors and suggest that these genes contribute to morphological differences between anterior (incisor) and posterior (molar) teeth within the mammalian dentition.
Topics: Alleles; Animals; Animals, Genetically Modified; Epithelium; Female; Gene Deletion; Incisor; Male; Mesoderm; Mice; Molar; Odontogenesis; Signal Transduction; Tooth Germ; Transcription Factor AP-2
PubMed: 33460639
DOI: 10.1016/j.ydbio.2020.12.017 -
The Angle Orthodontist Nov 2008To use published data to evaluate quantitatively the dental effects of noncompliance intramaxillary appliances in individuals with Class II malocclusion. (Review)
Review
OBJECTIVE
To use published data to evaluate quantitatively the dental effects of noncompliance intramaxillary appliances in individuals with Class II malocclusion.
MATERIALS AND METHODS
A literature search was carried out identifing 13 prospective or retrospective clinical studies matching inclusion criteria. Only appliances with conventional anchorage designs were considered for the review. The data provided in these publications were grouped and analyzed in terms of molar distalization, tipping and vertical movements, and incisor and premolar mesialization, tipping, and vertical movements.
RESULTS
Maxillary first molars showed distal crown movement and tipping greater than the mesial crown movement and tipping shown by incisors and premolars. Vertical movements of incisors and premolars were in general extrusive, but molars were intrusive or extrusive, depending on the study and the type of appliance used. Appliances that acted palatally seemed to display a smaller distal tipping movement, as well as smaller incisor and premolar mesial tipping movements, when compared with those that acted buccally. Friction-free appliances, namely the pendulum, produced a large amount of mesiodistal movement and tipping, if no therapeutic uprighting activation was applied.
CONCLUSIONS
Noncompliance intramaxillary molar distalization appliances all act by distalizing molars with a concomitant and unavoidable loss of anchorage, as revealed by incisor and premolar mesial movement. Buccal acting and palatal acting appliances demonstrate almost similar results, with palatal acting appliances showing less tipping. Friction-free palatal acting appliances appear to produce better molar distalizing effects, but with a concomitant notable loss of anchorage.
Topics: Bicuspid; Humans; Incisor; Malocclusion, Angle Class II; Maxilla; Molar; Orthodontic Appliance Design; Orthodontic Appliances; Prospective Studies; Retrospective Studies; Tooth Movement Techniques
PubMed: 18947282
DOI: 10.2319/101507-406.1