Ralph A.C.A. Voorsmit

Timing and transplant materials for closure of alveolar clefts: A clinical comparison of 296 cases*

A retrospective study of bone grafting of 296 clefts (165 unilateral and 131 bilateral was required) to answer questions about the most favourable timing and the most appropriate bone graft material. The results as such are not exceptional in comparison with earlier publications by the same or other authors, but it is of special interest that operations with different graft materials applied at different times in development, in (usually) a sufficient number of cases, can be compared together. The patients have been operated on during a period of 11 years, by the same surgeons, applying the same principles and techniques. It is shown that early secondary grafting, before the eruption of the canine, results in by far, the highest success rate. Similarly, chin bone is considerably better than any other type of transplant. Aspects of general planning, timing, technique and failures are extensively discussed. Besides the afore-mentioned most significant findings, it is also concluded that the results of grafting during osteotomies are better than they appear; that tertiary grafting is extremely difficult, and requires special surgical skill; that rib grafts score as high as iliac crest grafts and that materials other than these three types of bone should be avoided.

Open bite deformity in amelogenesis imperfecta part 1: an analysis of contributory factors and implications for treatment

Anterior open bite (AOB) is often seen in patients with amelogenesis imperfecta (AI). The skeletal and dental components were analysed in 15 patients with AI and AOB. Measurements on cephalometric radiographs and dental models were compared with those of 130 patients with AOB but without enamel anomalies. Skeletal components in the AI and non-AI group were comparable. The AI group showed omega-shaped dental arches and a reversed mandibular curve of Spee. Orthodontic treatment options are limited because of the conical form of the teeth, tight contacts in the posterior regions and the condition of enamel resulting in difficulties in bonding brackets. Fixation problems encountered during surgery are discussed. A multidisciplinary treatment is outlined consisting of a multi-segment Le Fort I osteotomy followed by prosthetic rehabilitation to stabilize occlusion for at least one year postoperatively.

Randomized prospective clinical trial of two implant systems for overdenture treatment: a comparison of the 2-year and 5-year results using the clinical implant performance scale.

In a prospective randomized clinical trial, edentulous patients were treated with dental implants and overdentures. The results of treatment with two IMZ implants connected by a Dolderbar, and a transmandibular implant (TMI) were compared. By using the clinical implant performance scale, the clinical and radiographic data were evaluated and compared after a two-year and five-year follow up. After the five-year follow up, significantly less problems and complications were recorded in the IMZ group than in the TMI group (Wilcoxon, P=0.03). When compared to the two-year follow up, there was, however, a gradual increase of scores on the clinical implant performance scale in the IMZ group, while in the TMI group only a slight increase was recorded.

Transmandibular implant versus intramobile cylinder implants: a randomized, prospective clinical trial

A randomized, controlled clinical trial was conducted to compare two different implant treatment modalities for edentulous patients with severely resorbed mandibles. In one modality (the IMZ group), two intramobile cylinder implants were placed, connected by a Dolder bar and provided with an overdenture, and in the other (the TMI group), a transmandibular implant with a triple bar and cantilever extensions was placed, likewise provided with an overdenture. The conditions of the overdentures, the peri-implant tissues, and the implants were evaluated. Orthopantomograms were taken for radiologic evaluation. An overall complication scale which took account of all aspects was devised to compare the results. The follow-up period was 2-4 years, with a mean follow-up of 3 years. The condition of dentures and oral hygiene aspects were comparable for both groups. The complication rate in the TMI group was significantly higher than that in the IMZ group. The scores on the complication scale resulted in a significant difference between the TMI and the IMZ groups (Wilcoxon, P = 0.0044).

Treatment of the edentulous mandible with a vestibuloplasty combined with Intramobil Zylinder implants: a 5-year follow-up

The long-term success of endosseous implants is related to healthy peri-implant tissues. Attached keratinized mucosa does not seem important for the prevention of soft tissue complications. Prevention of muscle attachment near the implants, however, seems more decisive for maintaining a favourable peri-implant environment. We treated 150 patients from 1990-91 with two Intramobil Zylinder implants and modified vestibuloplasty, 65 of whom were randomly selected for evaluation at 1 year; 48 of the 65 were also seen at 5 years. The vestibuloplasty was done by the technique of Pichler and Trauner, to prevent muscle pull and to create a thin layer of mucosa around the implants, and endosseous osseointegrated implants were inserted. The results show an adequately depended vestibulum with no muscle pull around the implants and significantly lower pocket depth after 5 years of follow-up compared with similar studies.

Open bite deformity in amelogenesis imperfecta Part 2: Le Fort I osteotomies and treatment results

Functional conditions, skeletal and dento-alveolar stability and condylar changes in 15 patients with mandibular hypoplasia, anterior open bite (AOB) and amelogenesis imperfecta (AI), who had undergone a Le Fort I osteotomy, were analysed after a mean follow-up of 5 years. Two patients underwent a one-piece Le Fort I intrusion osteotomy and 13 patients a multi-segment Le Fort I osteotomy. In three of these patients, an additional bilateral sagittal split osteotomy was performed. Thirteen patients underwent a genioplasty. Surgery was followed by prosthetic rehabilitation in 10 patients. Skeletal and dento-alveolar stability were analysed on lateral cephalometric radiographs and condylar changes on orthopantomographic radiographs. Transverse stability of the dental arches was analysed on dental casts. The treatment results in this group were compared with patients with similar skeletal features but without amelogenesis imperfecta. The harmony of the long faces was restored and a reasonable vertical stability of the maxilla was achieved, however, a slight open bite and tongue interposition was still present. The transverse stability of dental arches (60%) was disappointing. Rigid internal fixation produced better transverse stability. Progressive condylar resorption was seen in two patients (13%). Less occlusal stability could be achieved in patients with AI, but resulted neither in less skeletal stability nor in more susceptibility to morphological condylar changes.

Bone level changes in patients with transmandibular implants

PURPOSE In this article, the mandibular bone height in edentulous patients previously treated with a transmandibular implant was evaluated after the dentures were modified according to the latest prosthetic protocol. PATIENTS AND METHODS The bone height of 36 patients was measured on three radiographs; the first at the time of insertion of the implant, the second just before using the latest prosthetic protocol, and the third 1 year later. RESULTS A slight bone increase at the lateral posts and at the cortical screws mesial to these posts was measured. No significant bone increase was found above the lateral cortical screw. CONCLUSION The bone increase that is found in this study was not of the extent indicated in earlier reports.

Improvement in oral function following tumour surgery by a combination of tongue plasty by the Steinhäuser technique and osseointegrated implants

Oral functions such as speaking, chewing and swallowing are often reduced after ablative tumour surgery in the mouth and oropharynx. For restoration of at least a part of these functions, stable dentures and satisfactory mobility of the tongue are necessary. Dental implants can be used to achieve stable dentures. Pre-implant surgery, however, is often needed to reduce the amount of bulky tissue when myocutaneous flaps have been used for reconstruction, and to achieve adequate mobility of the tongue. A combination of tongueplasty by the Steinhäuser technique and osseointegrated implants will be described and discussed. Twelve patients have been treated by this technique between 1992 and 1995, with a mean follow up of 11.6 months. All patients reported an improved tongue mobility and ability to chew. Tongueplasty by the Steinhäuser technique with secondary epithelialization, in combination with osseointegrated implants, is a simple and effective means of improving oral function.