Severe Crowding Associated with Lower Canine Premature Resorption: Interceptive Treatment with Clear Aligners-A Pilot Study

BACKGROUND

Early mixed dentition represents a critical phase since crowding conditions can occur. The interceptive resolution of dental crowding allows favorable arch and occlusal development. The aim of the present investigation was to evaluate dentoalveolar changes of clear aligner treatment planned to manage lower incisor crowding, loss of arch length, and midline deviation in early mixed dentition.

METHODS

A total of 13 patients (7 females, 6 males, 9.4 ± 1.2 age) treated with clear aligners were selected. Arch dimensions and incisor inclinations were evaluated before (T0) and at the end of interceptive treatment (T1). A paired t-test was chosen to compare T1-T0 changes. The level of significance was set at 5%.

RESULTS

The greatest significant increase in mandibular width was observed at the level of the first deciduous molars (+2.44 ± 1.4 mm), followed by the second permanent molars (+2.16 ± 1.4 mm). Lower arch length and arch depth showed a statistically relevant increase (2 ± 0.6 mm and 4.5 ± 1.6 mm, respectively). The mean lower dental midline changes were statistically significant (1.42 ± 0.73 mm).

CONCLUSIONS

Early treatment with clear aligners, including the combination of transversal arch development, maintenance of leeway space, and guidance of eruption, represents a valid treatment strategy in early mixed dentition to manage arch crowding and occlusion development.

Evolution of the Terminal Plane from Deciduous to Mixed Dentition

(1) Introduction: Correct development and growth of the dental arches and occlusion in the deciduous dentition is crucial for physiological occlusion in the permanent dentition. The present study evaluates the evolution of the terminal plane and canine occlusion class in the same children from deciduous to mixed dentition. (2) Materials and methods: The study included 257 children (164 girls and 93 boys) aged 3-5 years in the first phase and 8-10 years in the second phase. The chi-square test was used for the comparison of qualitative variables, while analysis of variance (ANOVA) or the Mann-Whitney U-test, Kruskal-Wallis test, and Wilcoxon test were used in the case of quantitative variables, as applicable. Statistical significance was considered for p < 0.05. (3) Results: The most common terminal plane in the first phase of the study was a bilateral flush plane (70%), followed by distal and mesial, with few differences between them. In the second phase, the most common terminal plane was mesial, followed by bilateral flush and distal. There were no statistically significant differences according to gender. Canine occlusion in the first phase was predominantly bilateral class I, followed by class II and class III. Similar results were recorded in the permanent dentition, except for a lesser percentage of children with canine class II. Molar occlusion in the second phase was predominantly class I, followed by half cusp class II and full cusp class II and class III. (4) Conclusions: The present study shows that knowing the age range in which maximum dental development and growth in both arches occurs may contribute to avoiding malocclusions and the possible need for orthodontic-orthopedic treatment, resulting in improved outcomes and greater stability.

Rapid maxillary expansion treatment increases mid-facial depth in early mixed dentition

OBJECTIVE

To evaluate the effects of rapid maxillary expansion (RME) on mid-facial depth in early mixed dentition and to investigate the relationship between change in mid-facial depth and maxillary sinus and nasal cavity.

METHODS

A total of 35 patients with mixed dentition treated with a Haas expander were included in this retrospective study. All patients underwent a cone-beam computed tomography scan before and after rapid maxillary expansion. The Wilcoxon signed-rank test was performed to evaluate the changes in maxillary width, facial depth, maxillary sinus, and nasal cavity volume before and after expansion. Multiple linear regression analysis was applied to evaluate the correlations among them.

RESULTS

The hard and soft tissue facial depth in the middle third increased significantly (P < 0.001). The gain on the outer sagittal plane (1.04-1.52 mm) was slightly bigger than that on the inner sagittal plane (0.91-1.30 mm). Maxillary width and nasal cavity width increased 3.42 ± 0.93 mm (P < 0.001) and 2.25 ± 0.77 mm (P < 0.001), respectively, after treatment. A gain was also achieved in both nasal cavity volume (2,236.15 mm³, P < 0.001) and maxillary sinus volume (1,227.33 mm³, P < 0.001). Multiple linear regression analysis showed that with the increase in maxillary sinus volume, the facial depth increased as well (B = 0.455-0.683, P < 0.05). Also, statistically significant correlations were found between nasal width and nasal cavity volume (B = 0.384, P < 0.05).

CONCLUSION

The depth of the middle third face increased significantly. The facial depth increase was related to the enlargement of maxillary sinus volume, while the nasal cavity volume gain was related to the nasal width increase. This indicated that RME might enhance the fullness of the mid-face and facilitate the patency of nose breathing.

Investigation of maxillofacial morphology and oral characteristics with Turner syndrome and early mixed dentition

Turner syndrome is associated with an X chromosome abnormality in women and is characterized by infantilism, congenital webbed neck, and cubitus valgus. The aim of this study was to determine the maxillofacial morphology and oral characteristics of Japanese girls (mean age, 8.5 years) with Turner syndrome and early mixed dentition. Lateral cephalograms obtained at the first visit were used to analyze maxillofacial morphology. Oral characteristics were identified using orthopantomograms, intraoral photographs, and study casts. All patients received growth hormone. Lateral cephalograms showed a retrognathic maxilla and mandible and a small gonial angle. Nine patients had a high-arched palate. Nine patients had class II first molar relationship occlusion and one had mesial step-type occlusion. Three patients showed ectopic eruption of the maxillary first permanent molar accompanied by resorption of the maxillary second primary molar. Eruption of the permanent teeth tended to occur early. The median mesiodistal diameter of the maxillary central incisor was smaller than the Japanese norm. Ectopic eruption of the maxillary first permanent molar may be caused by lack of eruption space and a discrepancy between bone growth and timing of tooth maturation.

[Early orthodontic treatment of the patients with Class III malocclusion combined with the arches discrepancies using the own design appliance. Clinical case]

A 6-year-old boy with a skeletal Class III malocclusion was treated with the use of the fixed own design orthodontic appliance. The device includes acrylic-splint with a three-sided (Bertoni) screw mounted in them, an arc element in the region of the front teeth for protractive action on them, metal hooks for the face mask. Orthodontic treatment using that appliance allowed to normalize the upper dental arche in the sagittal and transversal directions. Thus, conditions for normal growth and development of the dentofacial complex were created, which is the main goal of early orthodontic intervention.