The dynamics in implantation for patients with clefts.
OBJECTIVE
To investigate the stresses and strains of an endosseous dental implant in patients with different types of cleft palate in a finite element model.


METHODS
Seven three-dimensional (3D) maxillary models were designed on a personal computer according to computed tomography slice data obtained from seven dry skulls. Next, computer-aided modification was performed on each model to produce three other 3D models with different cleft patterns. Thus, four model types with different cleft patterns were designed and termed NORM (without cleft), ALVEOLAR (only alveolar cleft), PALATAL (only palatal cleft), and COMPLETE (complete cleft). An implant was embedded into the molar region of each model, and a 300-N vertical load and 50-N horizontal load were applied to simulate mastication. Under these conditions, the stresses occurring at the implant-bone interface were calculated by finite element analysis.


RESULTS
Different stress patterns were observed between the models with a palatal cleft (PALATAL and COMPLETE) and those without palatal cleft (NORM and ALVEOLAR). Regarding vertical load application, greater stresses occurred in PALATAL and COMPLETE types than in NORM and ALVEOLAR types. On application of a horizontal load, though the stresses did not show quantitative difference, their vector patterns differed.


CONCLUSIONS
In patients with palatal clefts, characteristic stress patterns occur on the bone-implant interface during mastication. This should be taken into consideration when performing an implant treatment in patients with clefts.
Nagasao
Tomohisa
T
Department of Plastic Surgery, School of Medicine, Keio University, Tokyo, Japan. nagasao@sc.itc.keio.ac.jp
Miyamoto
Junpei
J
Jin
Hongmei
H
Tamaki
Tamotsu
T
Isshiki
Yasushige
Y
Kaneko
Tsuyoshi
T
Nakajima
Tatsuo
T
D000539:Alveolar Process / Q000002:abnormalities; D001696:Biomechanical Phenomena; D001732:Bite Force; D002972:Cleft Palate / Q000503:physiopathology*; D003198:Computer Simulation; D017076:Computer-Aided Design; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008409:Mastication / Q000502:physiology; D008437:Maxilla / Q000503:physiopathology* / Q000601:surgery; D008954:Models, Biological; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed
D015921:Dental Implants