1. Implants for upper incisor replacement in growing individuals: a histomorphometric study in adolescent beagle dogs.
K. Asscherickx*, B. Vande Vannet*, P. Bovend’Eerdt*, H. Wehrbein**
*Orthodontic Department, Vrije Universiteit Brussel, Belgium
** Orthodontic Department , University of Mainz, Germany
Objectives:
Congential partial anodontia or traumatic tooth loss might compromise facial esthetics in children and adolescents. The viability of implant use in these patients is questioned since dental and skeletal growth are still present. Difference in incisor edge level might occur after several years1 and interdental papilla can be absent, due to reduction in alveolar crest height2 .
The aim of the present study was to evaluate histomorphometrically the influence of implant placement in the upper front region in growing individuals on marginal bone level around the neighbouring teeth and on the alveolar growth in this region.
Materials and
Methods:
Four out of 5 adolescent (6.5 months old) beagle dogs received a dental implant immediately after extraction of tooth 1.1. All animals were subjected to a scheme of sequential point labelling with vital stains every 6 weeks (figure). After a period of 25 weeks, dogs were sacrificed and specimens prepared for histological evaluation. Marginal bone level of the implant and lateral incisor were compared between the test side and the control side and between test dogs and control dog. Composite images of left and right side in each dog were obtained and cemento enamel junction of 1.2 or 2.2 was used as reference line (click once). The amount of alveolar growth was evaluated by fluorescence microscopy (click once more).
Fluorescence microscopic images of bone level between teeth 1.1 and 1.2 in the control dog (I) and bone level between implant and tooth 1.2 in one test dog.
Measurements performed between 12 weeks (Tetracycline) and 24 weeks (Calcein Green).
Composite images of 1 test dog (I) and control dog (II)
Distances:
CEJ 2.2 mesial and MBL mesial to 2.2 (a)
CEJ 2.2 mesial and MBL distal to 2.1 (b)
CEJ 1.2 mesial and MBL mesial to 2.1 (c)
CEJ 1.2 mesial and MBL distal to implant or to 1.1 (d)
(CEJ: cemento enamel junction;
MBL: marginal bone level)
Experimental design
Results:
Marginal bone level: MBL mesial to tooth 2.2 in the test dogs (average 1.16mm) was comparable to MBL mesial to tooth 2.2 in control dog (1.19mm). MBL mesial to tooth 1.2 was 2.05mm lower in test dogs (3.21mm on average) than in control dog (1.13mm). Alveolar growth: During the period from 9,5 to 12,5 months old, alveolar growth between teeth 2.1 and 2.2 was comparable between test dogs (average 264,25µm) and control dog (246µm). Alveolar growth between 1.1 and 1.2 was 223µm in the control dog and zero between the implant and 1.2 in the test dogs. Only bone remodelling was present between the implant and tooth 1.2.
Conclusions:
These findings, as evaluated by this method and under these circumstances, demonstrate that both arrest in alveolar growth and bone loss due to implant insertion in the upper front region in adolescent beagle dogs, contribute to a total decrease of marignal bone level of 2.05mm as compared to a situation without implant over a period of 6months (comparable to 3.5 years in humans). Extrapolation to humans must be done with caution.
References:
1. Thilander B; Ödman J, Lekholm U. Orthodontic aspects of the use of oral implants in adolescents: a 10-year follow-up study. Eur J Orthodontics 2001;23:
2. Tarnow DP, Magner AW, Fletcher P. The effect of the distance from the contact point to the crest of bone on the presence or absence of the interproximal dental papilla. J Periodontol 1992; 63(12):995-6.
88th CONGRESS EOS 2012 Santiago de Compostela (Spain) – 18 to 23 june 2012