Skeletodental patterns in patients with multiple congenitally missing teeth

Objectives: To determine the skeletal relationships in patients with hypodontia and analyze the effects of severity and pattern. Materials and Methods: Pretreatment lateral cephalograms from 277 patients with hypodontia, categorized by the number of missing teeth as mild (1-2), moderate (3-5), or severe ($6), were digitized recording angular measurements and ratios and compared with published norms matched for age and gender. Pattern was determined as mandibular, maxillary, bimaxillary, bilateral, anterior, posterior, and anteroposterior. Linear regression models assessed relationships between number of missing teeth and cephalometric parameters, controlling for the pattern of hypodontia. Results: For every additional missing tooth, SNA, SNB, and ANB decreased 0.3u, 0.1u, and 0.2u, respectively; this was clinically significant for .4, .10, and .5 missing teeth, respectively. Mandibular to cranial base ratio decreased 0.3% for every additional missing tooth; this was clinically significant for .10 missing teeth. The MMPA decreased 0.3u for every additional missing tooth; this was clinically significant for .7 missing teeth. Percentage LAFH decreased 0.2% for every additional missing tooth; this was significant for .7 missing teeth. Jarabak ratio increased 0.2% for each additional missing tooth; this was clinically significant for .10 missing teeth. Anterior hypodontia significantly decreased most cephalometric parameters. Conclusions:Patients with hypodontia demonstrated a tendency toward a Class III relationship, caused by decreased maxillary and mandibular angular prognathism and MnCB ratio, though the effect was greater on the maxilla than the mandible. Clinical significance was only associated with severe hypodontia. Vertically, there was a tendency toward decreased MMPA and %LAFH; this was clinically relevant only with severe hypodontia. Anterior hypodontia had a significant effect on skeletal relationship. (Angle Orthod. 2010;80:699-706.)

Section: Discussionmentioning

confidence: 99%

A cephalometric study to investigate the skeletal relationships in patients with increasing severity of hypodontia

Acharya¹,

Jones²,

Moles³

et al. 2010

“…[12][13][14][15][16][17][18][19][20][21][22] In the present study, we made an extensive investigation of the possible influences of the congenital absence of mandibular incisors on the mandibular symphysis morphology using area measurements in addition to traditional measurements. The mandibular symphysis area was significantly smaller in groups 2M and M than in group C, although neither mandibular symphysis height nor thickness showed any significant differences between the groups.…”

Section: Discussionmentioning

confidence: 99%

“…Several studies have shown the association of hypodontia with smaller cranial base length [12][13][14] and angle, 12,15 more retrognathic [15][16][17][18] and shorter maxilla, [12][13][14]17,19 more prognathic mandible, [12][13][14]20 smaller mandibular plane 13,15,20 and sagittal jaw relationship angles, 15,16 straighter facial convexity, 15,17,18 greater retroclination of maxillary 12,[14][15][16]18 and mandibular incisors, 12,[14][15][16] larger interincisal angle, 12,14,15,18 and shorter lower anterior facial height. 13,15 However, some other studies have revealed that hypodontia has little or no effects on craniofacial morphology.…”

Section: Introductionmentioning

confidence: 99%

Congenitally Missing Mandibular Incisors and Mandibular Symphysis Morphology

Endo

Ozoe

Kojima

et al. 2007

Objective: To explore the association between congenital absence of permanent mandibular incisors and craniofacial and mandibular symphysis morphology in Japanese orthodontic patients. Materials and Methods: A total of 27 girls with one or two congenitally absent mandibular incisors (group M) were selected and divided into group 1M (16 girls with the absence of one incisor) and group 2M (11 girls with the absence of two incisors). In addition, 20 other Japanese girls without hypodontia and with little or no mandibular incisor crowding were enrolled as a control (group C). Using the lateral cephalogram of each subject, 17 angular, 8 linear, and 3 area measurements were made for evaluation of craniofacial and mandibular symphysis morphology. The cephalometric data thus obtained were statistically analyzed and compared between the groups. Results: A significantly greater retroclination of the retained mandibular incisors was found in group 1M than in group C. Groups 1M and M showed a significantly greater retroclination of mandibular alveolar bone than group C. Groups 2M and M exhibited a significantly smaller mandibular symphysis area than group C. Conclusion: The retroclination of the mandibular incisors and alveolar bone and the reduced mandibular alveolar bone area should be taken into consideration in planning orthodontic treatment on patients with congenitally missing permanent mandibular incisors.

“…1,2 It is one of the most common dental anomalies in the permanent dentition. [3][4][5] To describe the phenomenon of congenitally missing teeth, hypodontia is the term most frequently used. 6 Another term used to describe a reduced number of teeth is oligodontia.…”

Section: Introductionmentioning

confidence: 99%

Tooth sizes in nonsyndromic hypodontia patients

Gungor

Türkkahraman

2013

Objective: To evaluate and compare the sizes of teeth in mild and severe hypodontia patients with those of healthy controls. Materials and Methods: Dental casts of 154 patients with two or more congenitally missing teeth were obtained. Patients were divided into two groups according to severity of hypodontia. Group I (mild) consisted of 118 patients with two to five missing teeth. Group II (severe) consisted of 36 patients with six or more missing teeth. In addition, a control group was included, which consisted of 50 patients who had an Angle Class I jaw relationship and no missing teeth. Mesiodistal and labiolingual dimensions of the teeth were measured with a digital caliper on dental casts. The independent-samples t-test was used to evaluate the effect of gender on measurements. Intergroup differences for mesiodistal and labiolingual dimensions were evaluated with analysis of variance and post hoc Tukey tests. Results: Statistically significant differences were found between girls and boys with hypodontia in the mesiodistal dimension of the mandibular first premolar and the labiolingual dimension of the mandibular lateral incisor (P , .01). Mesiodistal and labiolingual width measurements of the teeth of hypodontia patients showed statistically significant differences compared with the control group (P , .05). Most teeth showed significant dimensional reductions in severe hypodontia compared with mild hypodontia (P , .05). Conclusions: The mesiodistal and labiolingual dimensions of teeth in both mild and severe hypodontia groups were smaller than those in control subjects. The reduction in size was more excessive in the severe hypodontia group. The teeth showing the greatest difference in tooth dimensions were the maxillary lateral incisor (in mesiodistal dimension) and the mandibular canine (labiolingual dimension). (Angle Orthod. 2013;83:16-21.)