Clinical statistics of 43 cases using midpalatal implants and observations of removed implants tissue after orthodontic treatments

Midpalatal implant was developed as a new orthodontic implant system in 1996, Switzerland. Until now, there is no clinical statistical report involved in the midpalatal implant including the removal in Japan. The aim of this study is to report clinical statistics of orthodontic patients using the midpalatal implants and to propose an application of collagenous sponge material to the defect after the removal of the midpalatal implant. Forty-three patients (thirty-four females and 9 males, operation age: 15 years 3 months to 39 years 5 months, mean age: 21 years 10 months) received one screw-type endosseous implant each (lengths: 4 or 6mm, diameter: 3.3mm; Orthosystem®, Institute Straumann, Switzerland) for maximum orthodontic anchorage. The success rate of the initial midpalatal implants (fixture length: 6mm) was 96.3% (26/27), while the success rate of the length of 4mm was 75.0% (12/16). In all cases, the success rate of the initial midpalatal implants was 88.4% (38/43). Five palatal implants were lost, but the osseointegrations of all 5 cases were achieved by the second implantations. In non-decalcified sections of the removed material, the pure titanium fixture connected with cortical bone, and the network of osteocytes and osteon structure were observed. At the removal after dynamic treatments, metal-like stains were adhered on the surfaces of the defect. The foreign bodies were removed from the defect surfaces by using a curette and/or a bar as possible. As our ideas for bone healing, available collagenous material (TERUPLUG®) was filled in the bone defect, and then covered with an antibiotic ointment (Achromycin carboximethylcellulose sodium). The bioabsorbable medical material consists of 90% atellocollagen and 10% denatured collagen derived from bovine skin. All patients had no problems after accepting the midpalatal implants and the collagenous material filling after the removal. We believe that this sponge technique could contribute to bone healing after the explantation of the midpalatal implant.