Wednesday, October 28, 2015

Longitudinal study of tooth formation and root resorption

Department of Pediatric Dentistry
Lutheran Medical Center

Resident’s Name: John Kiang                                                            Date: 10/27/15
Article Title: Longitudinal study of tooth formation and root resorption.
Author(s): Fanning, E.A.
Journal: NZ Dent J
Date: (1961) 57: 202-217.
Major Topic: Tooth development and root resorption
Type of Article: Longitudinal Study
Main Purpose: designed to provide norms of tooth formation and root resorption for the maxillary incisors and all mandibular teeth except third molars
Key Points/Summary:
  • Lateral skull radiographs were taken at birth, two weeks, at three month intervals to the age of one year, and thereafter at six-monthly intervals from the first to the fourth year.
  • Intra-oral radiographs of max and mn incisors taken at six-monthly intervals between 4 and 11.5 years of age.
  • Fourty-eight males and 51 females who had the most complete record of radiographs were chosen.
  • Sex differences in tooth formation (increased as children got older) and root resorption were observed; biggest difference is the mn canine in which root resorption begins earlier in females
  • Tooth to shed first, mn  first incisor had least sex difference; with greatest diff resorption of the deciduous canine and second molars
  • Rate of growth decelerated when the tooth crowns were completed and root development commenced. Root development accelerated while the tooth was in active eruption.
  • Clinical emergence of the perm teeth generally took place in the time interval between two-thirds of the root being formed and commencement of apical closure.
  • Association appeared to exist between dental caries of the mesial or distal surfaces of the deciduous molar crown and the resorption of the corresponding root (caries eliciting an inflammatory tissue response causing increased root resorption).
  • After extraction, the eruption of the premolar did not change; but if there was presence of long standing necrosis/infection, the premolars eruption was accelerated
  • Early eruption and clinical emergence occurred if the extraction coincided with the eruptive phase of the premolar.
  • Initial spurt in eruption of the premolar followed very early extraction, but this spurt leveled off and the tooth then remained stationary and erupted later than its antimere.
  • Agenesis of a permanent tooth was followed by delayed root resorption of the deciduous precursor, but this delay was less marked in the anterior.
  • Fusion of deciduous incisors resulted in exfoliation at a time intermediate between the first and second incisors on the opposite side.

Orthodontic Procedures after Trauma

Department of Pediatric Dentistry
Lutheran Medical Center

Resident’s Name:                                                                                                        Date:
Article Title: Orthodontic Procedures after Trauma
Author(s): Fields, Christensen
Journal: Pediatric Dentistry
Date: 2013
Major Topic: Trauma
Type of Article: Conference Paper (Opinion)
Main Purpose: To review the available evidence regarding orthodontics as an adjunct to post-oral trauma treatment for permanent teeth
Key Points/Summary:
·      Studies have been continuously published that support the increased risk of trauma with increasing overjet and inadequate lip coverage
o   Early orthodontic treatment to retract the incisors or early reduction of the overjet by growth modification should reduce the incidence of oral trauma
·      It is important to stress the importance of the mouth guard in prevention of oral injuries.
·      Orthodontics as an Adjunct to PostTrauma Treatment
o   Primary treatment-urgent care provided as soon as possible after traumatic incident
o   Secondary treatment-consists of monitoring the pulp and periodontal tissues for healing and treatment; it also involves orthodontic treatment of displaced teeth.
§  Trauma ortho kit: hand instruments, cheek retractors, self-etching primer or traditional etchant, self-ligating or twin brackets, flexible NiTi wire, cell-phone
o   Tertiary treatment-addressed the ramification of orthodontic treatment for previously traumatized teeth; timing of orthodontic treatment after trauma is an unresolved issue (3, 6, 12 months)
·      Trauma during orthodontic treatment: Teeth experiencing trauma during ortho tx are significantly more likely to have pulpal necrosis than orthodontic or trauma only teeth

Level of Evidence: Opinion in Orthodontic Journal

The ‘functional matrix’ hypothesis current concepts and confilicts

Department of Pediatric Dentistry
Lutheran Medical Center

Resident’s Name:             Leslie M Slowikowski                                                        Date: 10/28/2015
Article Title: The ‘functional matrix’ hypothesis current concepts and confilicts
Author(s): Fuller M.D.Sc.; West M.D.Sc., B.Sc.
Journal: Australian Orthodontic Journal
Date:  1986
Major Topic: functional matrix
Type of Article:  literature review
Main Purpose: Review support/problems with functional matrix theory
Key Points/Summary:  There is a clear idea of how the face grows and where it grows, but why it grows is not fully understood.  There are three hypotheses, which have been proposed to account for the control of growth of the skull. 

Classic approach: control for skull growth largely to intrinsic genetic factors.  Sicher and Van Limborgh held this theory.  That apart from minor modeling which could be caused by local environmental factors such as muscular forces, bond growth was independent.  Growth of skull and soft tissues were independent of each other. 

Second Major hypothesis:  Scott.  He proposed that intrinsic, growth-controlling factors were present only in the cartilage and in the periosteum.  He claimed that the growth of the sutures was secondary and entirely depending on the growth of cartilage and adjacent soft tissues. 

Moss’s ‘functional matrix’:  hypothesis held that the head can be considered as a series of encapsulated volumes, each of which subserves a basic function – digestion, respiration, vision, olfaction, audition, etc. The soft tissue of each capsule, as well as it’s contents (brain, eyeball, spaces, etc.) constitutes a group of functional matrices, each of which, as it grows and functions, serves to more, shape and maintain those specific osseous parts with which it is a associated. 

Inference which can be drawn from studies of the suture: experimental evidence ahs given great support to the hypothesis that sutural growth is secondary.  Support of functional matrix. 

Inferences which can be drawn from studies of cartilage: studies showed that poor or irregular growth happens intrinsically, but the nasal septal cartilage will grow after transplantation.  But never the less most studies are consistent with Moss

The role of mandibular condyle:  studies can be interpreted differently and fails to clarify the mechanisms of mandibular growth and does not necessarily support Moss. 

The role of the nasal septum:  There seem to be numerous data that support the contention that the cartilaginous nasal septum plays an important role in midfacial translative growth.

Inferences drawn from the study of spaces:  The evidence dealing with the effect of spaces or their function is scant. 

Inferences drawn from the study of neurotrophism:  studies have been completed and they could not support the conclusion that trophic effects constitute a major factor in the regulation of craniofacial growth. 

The ‘functional matrix’ hypothesis might not be ‘the answer,’ it has nevertheless contributed significantly to the extension of knowledge in the field of craniofacial growth. 

Assessment of Article:  Level of Evidence/Comments: III

Prediction of Tooth Emergence

Department of Pediatric Dentistry

Lutheran Medical Center


Resident’s Name: John Diune                                                                Date: 10/28/2015

Article Title: Prediction of Tooth Emergence
Author(s): Anna-Marie Grøn
Journal: Journal of Dental Research
Date: 1962
Major Topic: Growth and Development
Type of Article: cross-sectional study
Main Purpose: To try to narrow the time interval of estimated time of eruption of certain teeth considering root development (4 phases) and skeletal development and chronological age.
Key Points/Summary:
  • Materials and Methods:
    • sample studied consisted of 874 healthy, Caucasian children (434 males / 440 females) from lower socio-economic group in Greater Boston area
    • selection based on actual “emergence” (tooth that had just pierced the gingiva but was no more than 3mm above gingival level) of one or more of following teeth: permanent maxillary incisors and all permanent mandibular teeth (except 3rd molars)
      • Exclusion: those with insufficient space for eruption and early loss of deciduous teeth
    • Radiographs taken of left hand and wrist and of emerging tooth and its antimere
      • Tooth formation estimated using 4 stage rating: approximate attainment of ¼, ½, ¾, and full root length (w/ open apex)
      • Hand radiographs analyzed according to method described by Greulich and Pyle (Radiographic Atlas of skeletal Development of the Hand and Wrist 1959)
  • Results and Discussion (MAIN Takeaways)
    • Majority of all teeth studied attained approximately ¾ of root development at time of clinical emergence (formation of less than ¼ root length or a closing apex was never observed)
    • Mandibular 1st molar and central incisor generally had about ½ of root formed at emergence
    • Typical mandibular canine and 2nd molar emerge after passing the ¾ root development mark
    • It was found that using estimated root development stage gives a better precision than from chronologic age, and chronologic age gives a better precision than skeletal age
  • Consideration of problems with predictive methods
    • Predicting skeletal age is very difficult; from results either tooth emergence is not closely associated with skeletal age, or difficulties in measuring skeletal age concealed the association
    • For estimating eruption based on root development, will need to factor in the time duration that the tooth is in a given stage; whether tooth is at beginning of a given stage of development or at the end  (the duration a tooth is in a given stage is also variable; author cited Fanning for estimated duration of a tooth in a given stage)
Assessment of Article:  Level of Evidence/Comments:


Treatment response and stability of slow maxillary expansion using Hass, hyrax, and quad-helix appliances: A retrospective study

Department of Pediatric Dentistry
Lutheran Medical Center

Resident’s Name: Nicholas Paquin                                                                             Date: 10/28/2015

Article Title: Treatment response and stability of slow maxillary expansion using Hass, hyrax, and quad-helix appliances: A retrospective study
Author(s): Huynh T, Kennedy D., Joondeph D, Bollen AM.
Journal: Am J Ortho and Dentofacial Ortho
Date: 09/2009
Major Topic: Slow palatal expansion
Type of Article: Retrospective study
Main Purpose: Determine stability and effectiveness of different slow palatal expanders.
Key Points/Summary:
- Retrospective study, short and long term effects of slow maxillary expansion with Haas, hyrax, and quad-helix appliances on posterior crossbite correction stability, and maxillary intermolar width and angulation, in the deciduous and mixed dentition.
Methods: The inclusion criteria were models and treatment notes of patients with posterior cross-bite at the start of treatment (T1), after correction (T2), and at least 2 years posttreatment (T3). Exclusion criteria were craniofacial anomalies, fixed appliance use, or more than 1 expander type. From 312 consecutive expansion patients, 74 Haas, 41 hyrax, and 45 quad-helix subjects were evaluated regarding posterior crossbite correction, intermolar width, and angulation and compared with published norms to separate treatment effects from growth. The mean ages at T1, T2, and T3, were 8, 9 and 13 years.
Results: There were no significant differences in posterior crossbite corrections stability or treatment responses at T2 and T3 among the 3 expanders. Expansion increased intermolar width by 5mm and tipped each molar by 2.3 degrees. At least 2 years after expander removal, molar width decreased by 1.3mm and the molars uprighted by 6 degrees. Compared with noncrossbite norms, posterior crossbite subjects had narrower intermolar width before treatment and greater width after expansion, and were slightly wider at least 2 years posttreatment. Both younger age at T1 and retainer use resulted in statistically greater intermolar width at T3.
Conclusions: 84% of posterior crossbite correction remained with about one third of the initial expansion lost; retainer use and early treatment provided increased intermolar width. Haas, hyrax, and quad-helix appliances were equally effective. Slow maxillary expansion altered the posterior crossbite patients’ maxillary widths from narrower to slightly wider than the widths of the noncrossbite norms.

Take home:
-The maxilla is symmetrical, but with a functional shift it can lead to skeletal asymmetry. If the cross bite with functional shift is corrected early, symmetry improves.
-Slow maxillary expansion, in young patients, provides the maximum rate at which the midface sutures can adapt, with minimum tearing and hemorrhaging compared to MPE. Studies show it can produce a more stable result than MPE, however the samples were small.
- In younger patients, sutures open more easily that older (pubescent) patients, so light force is acceptable, and allows better tissue response.
-The Haas, hyrax and quad-helix are equally effective for posterior cross bite correction, intermolar expansion and intermolar angulation.

Early treatment of palatally erupting maxillary canines extraction of the primary canines.

Department of Pediatric Dentistry
Lutheran Medical Center

Resident’s Name: Mark Dawoud, DMD                                           Date: 10/28/15
Article Title: Early treatment of palatally erupting maxillary canines extraction of the primary canines.
Authors: Ericson et al.
Journal: European Journal of Orthodontics
Date: 1988
Major Topic: Ectopic canines
Type of Article: Prospective study
Main Purpose: Analysis the effect of extraction of primary canine on palatally erupting maxillary canines in young individuals.

Key Points:
·      In 36 of the 46 canines of children aged 10-13 years of age (78%) the palatal eruption changed to normal; 23 already showed improved positions after 6 months and 13 after 12 months. No new cases normalized after 12 months.
·      The permanent canines’ impaction is 2nd only to third molars. 85% of the time they a impacted palatally and 15% of the time they are impacted lingually.
·      Resorption of the permanent incisor roots is always a risk.

Level of Evidence/Comments: Extraction of the primary canine is the treatment of choice in young individuals to correct palatally ectopically erupting maxillary canines provided that normal space conditions are present and no incisor root resorptions are found.

Internal Validity: II-B;