Thursday, October 26, 2017

Growth studies of the dentition: A review

Department of Pediatric Dentistry
NYU Langone

Resident’s Name: Suhyun  Rue                                        Date:10/18/17

Article Title: Growth studies of the dentition: A review.
Author(s): Moorrees, C.F.A., Grøn, A.M., Lebret, L.M.L., Yen, P.K.J., Frölich, F.J.
Journal:  American Journal of Orthodontics
Date:  June 1969
Major Topic: Changes in growth in individuals over time
Type of Article: Systematic review
Main Purpose: To determine predictability to determine when to intervene for orthodontic treatment
Key Points/Summary:
- To gain a perspective of dental development as a prerequisite for orthodontic diagnosis till the mixed dentition, growth research at the Forsyth Dental Center has been concerned with topographic aspects, namely, attempts to define the magnitude of change and particularly the differences in growth increments among children.
- Overbite is a symptom determined not only by the position and inclination of the incisors but by a lot of factors involving disproportionate relationships between the heights of the alveolar processes in the incisor and posterior segments of one or both jaws and even disproportions of -vertical facial development. The correction of overbite should be conducted preferably during periods of active vertical growth of the face.
-Vertical changes ( alveolar growth, overbite), available space, arch length, intercanine distance, mesiodistal crown diameters, incisor transition
-Vertical changes range widely, but overbite is similar at ages 5-6 and 16-18.
-Mandibular incisors erupt in crowding normally (1.6mm), but will self correct when fully erupted and properly angulated (called incisor transition)
- Since the leeway space on each side is greater in the mandible (2.2 mm.) than in the maxilla (1.2 mm), neutrocclusion of permanent molars is achieved from the initial cusp-to-cusp relation by greater mesial shifting of the mandibular molar.
- The mean increase in the intercanine distance is virtually completed after full eruption of the crown of the permanent lateral incisors
- Findings for available space, arch length, inter canine distances, and mesiodistal crown diameters in the permanent dentition at the age of 16 to 18 years compared to age 4 in individuals. There is a variation between these two age levels. It is evident that the changes are exceedingly variable in the growth records of these nine individuals.

Class II cases
- Dental development in the untreated malocclusion sample is of specific interest to the orthodontist in determining whether or not self-correction occurs. Examination of these serial dental casts revealed differences among the Class II malocclusions, the Division 1 category was divided into two subgroups. One characterized by moderate overjet, severe crowding of permanent maxillary incisors, and a V-shaped maxillary dental arch and (2) characterized by flaring and spacing of incisors, marked overjet, and a parabolic arch form. In addition, a borderline category (that is, malocclusion characterized by upright, well-aligned maxillary incisors and a slight to moderate overjet) was found to occupy an intermediate status between the Class II, Division 1 and Division 2 malocclusions defined in the classic sense

Key Points:
-Vertical changes (alveolar growth and overbite), available space, arch length, intercanine distance, mesiodistal crown diameters, incisor transition are all variable and change throughout individual growth patterns and tend to be unpredictable.
- The increments in arch size, the changes in available space, and the differences in the crown size of deciduous and permanent teeth are not correlated. Because of marked individual variations, mixed·dentition analysis requires attention to a number of variables.
- It may be concluded that mixed-dentition treatment of Classes I and II malocclusions can be the most efficient orthodontic care for a specific patient if warranted by a carefully made analytical diagnosis
Assessment of Article:  Level III

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