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Biomedical subjects

H Bosker

Publications and source records attributed to H Bosker.

18 recordsLinked to original sources
PubMed1996

Functional and cosmetic reconstruction of the facial lower third associated with placement of the transmandibular implant system.

PURPOSE: Conventional preprosthetic procedures have typically focused on improvement of denture base stability and retention and have ignore patients' concerns about facial appearance and articulation difficulties. Soft tissue procedures have been developed, combined with insertion of the transmandibular implant (TMI) system through a submental incision, for functional and cosmetic reconstruction of the lower face to improve speech and facial esthetics, and prevent gingival hyperplasia along the lateral posts of the implant. PATIENTS: The surgical procedure was evaluated in 146 patients with slight, moderate, severe, and extreme mandibular atrophy classified according to the proportion of muscle origin loss on the edentulous mandible. Preoperative, 3-month, and 1-year postoperative full-face and profile photographs were taken. Patients also were questioned about their satisfaction with their facial appearance and speech at these intervals. Gingival hyperplasia along the TMI posts was scored as present or absent. RESULTS: Satisfaction with the soft tissue reconstruction in 146 patients treated according to this protocol was high, with almost every patient describing the positive comments they had received from their friends and relatives. Postoperatively, none of the patients requested a temporary denture to use during the 12-week incorporation period, although this was a common cosmetic and speech concern preoperatively. Gingival hyperplasia secondary to muscle pull was controlled satisfactorily. CONCLUSIONS: With the described technique for placement of the TMI system, not only is masticatory function improved, but also the lower third soft tissues of the face are functionally and cosmetically reconstructed to the satisfaction of the patients.

Adipose Tissue↗
PubMed1994

The transmandibular implant: from progressive bone loss to controlled bone growth.

PURPOSE: In a prospective study, 146 consecutive transmandibular implant (TMI) patients were treated according to revised surgical and prosthetic protocols to induce and control bone growth. Revisions included 1) placement of transosseous posts and cortical screws between the mental foramina so that two threads extended beyond the alveolar crest of the mandible without protruding through the mucosa and 2) fabrication of an implant-borne prosthesis that rested on the retromolar pads with a gap of 2 mm between the denture base and the mucosal tissues in the saddle areas. PATIENTS AND METHODS: Measurements of the height of the mandible were made using a digital millimeter calliper and panoramic radiographs, with the enlargement calculated for each radiograph. The follow-up period ranged from 18 to 51 months. RESULTS: Bone growth was present in 131 of the 146 patients whereas the bone resorption was arrested in the remaining patients. Increase in bony apposition varied from 9 mm in patients with severe mandibular atrophy to 2 mm in patients with mild atrophy. CONCLUSION: The revised surgical and prosthetic protocols for TMI insertion and rehabilitation are advocated to prevent further alveolar resorption and to promote bone growth in patients with mandibular atrophy.

Adult↗
PubMed1991

The transmandibular implant: a 13-year survey of its use.

During the period from August 1976 until July 1989 the transmandibular implant was introduced in a total of 31 oral and maxillofacial surgery departments in the Netherlands and 1,466 patients were treated. This study includes 1,356 treated patients from 28 departments. The treatment course of 1,201 patients (89.6%) was uneventful. Of the 157 complications, 58 related to the anatomic contour of the mandible, 49 to the surgery, 25 to the prosthetic reconstruction, 8 to the psychosocial attitude of the patient, 8 to the use of medication, 5 to trauma, and 4 to the presence of a skin graft. Treatment of the complications included removal of the implant in 44 patients; in 106 patients the complication was treated satisfactorily. In the remaining 7 patients, hypesthesia was present. The reasons for the removal of the 44 implants were infection (11), operative error (5), premature loading of the implant (3), insufficient width of the mandible after a visor osteotomy (1), loss of osseointegration caused by the prosthesis (14), psychological problems (4), trauma (3), drug-related gingival hyperplasia (2), and inexplicable pain (1). The present survey shows a consistent success rate of 96.8%.

Adult↗
PubMed1990

Characterisation of decay of frequency induced potentiation and post-extrasystolic potentiation.

STUDY OBJECTIVE: The aim was to elucidate the processes underlying the beat by beat decay of frequency induced and post-extrasystolic potentiation. DESIGN: The ventricular pacing protocol consisted of a "priming period" followed by a "decay" period of pacing at 1 s intervals, characterised by a decaying potentiation of left ventricular (LV) dP/dtmax; these were identified as test beats 1,2,3,4,5. The magnitude of potentiation of test beat 1 (P1) was increased both by increased priming frequency (frequency potentiation) and by alternately shorter priming intervals (paired pulse stimulation) at a given average frequency (post-extrasystolic potentiation). The exponential decay constant (P2) and the asymptotic value (P3) were determined and compared with the measured values and with the slope of the linear relationship between the contractility of one beat and that of the preceding beat. The lowest values after decay were related to the magnitude of preceding potentiation. EXPERIMENTAL MATERIAL: Six anaesthetised dogs with induced heart block and beta adrenergic blockade were used. Beat to beat interval was controlled by ventricular pacing from a programmable stimulator. MEASUREMENTS AND MAIN RESULTS: Contractility of each beat was assessed from maximum rate of rise of LV pressure (LVdP/dtmax) obtained from an intraventricular micromanometer. The asymptotic value of the exponential fit to the decay of potentiation (P3) was found to be below the measured nadir value, which was followed by an increase in LVdP/dtmax to the final steady state value P4. The decay constant (P2) was found to be equivalent to the natural logarithm of the slope of the linear relationship between the contractility of one beat and that of the preceding beat; it was unaffected by priming frequency or interval at a given average priming frequency. The asymptote P3 was inversely related to P1. CONCLUSIONS: P1 was interpreted as the expression of accumulation of activator in an internal release store; P3 was interpreted as a manifestation of negative feedback control of activator entry by the released activator itself, and the slow recovery to P4 as due to the slow lengthening of action potential duration and/or recovery from accumulation of an intracellular metabolite or ion.

Action Potentials↗
PubMed1989

The transmandibular implant: a 12-year follow-up study.

A clinical study of the use of the transmandibular implant for reconstructing severely atrophic mandibles in preparation for an implant-borne dental prosthesis was performed. This study included 368 patients with a mean height of the mandible of 10 mm. They were examined clinically, radiographically, and by means of a questionnaire. The follow-up period for 185 patients was 5 years or more, and 55 were followed 10 years or more. Removable dentures were made for 350 patients, and fixed bridges for 18 patients. Forty-three patients had reversible complications, one patient had unilateral hypesthesia, and six patients had their implant removed. Reversible complications of infection, gingival hyperplasia, loading of individual posts, and fenestration of threads were controlled without deleterious effects on the gingival, mucosal, or osseous tissues. The transmandibular implant system was shown to successfully restore function of the severely atrophic mandible in a more predictable manner than augmentation procedures.

Adult↗
PubMed1989

Evaluation of satisfaction of denture wearers with the transmandibular implant.

121 edentulous patients with severe resorption of the mandible (average 10.0 mm, measured in frontal area) who received a transmandibular implant were evaluated from 2 to 8 years after insertion of the implant. Patients' opinion about the implant and denture function after insertion were evaluated using a questionnaire. The results showed that most of the patients (91%) were satisfied because of improved denture function. There were few complaints about looseness, pain and difficulty with chewing. 96% of the patients considered their implant as being a valuable adjunct to denture retention.

Adult↗
PubMed1989

Late secondary autogenous bone grafting in cleft patients comparing mandibular (ectomesenchymal) and iliac crest (mesenchymal) grafts.

A comparative study has been performed between two groups of 25 alveolar cleft patients. The cleft area was restored with mesenchymal (iliac crest) and ectomesenchymal bone (mandibular symphysis). The results are discussed; the mandibular symphysis is a reliable donor site; the ectomesenchymal graft is better incorporated, significantly less resorbed, and the orthodontic treatment postoperatively is not altered.

Adolescent↗
PubMed1985

On the change of cardiac action potential with age: a study in dogs.

The action potential duration (APD) was measured using an Ag-AgCl electrode, in open chest anaesthetised dogs (n = 8) and puppies, 4 to 6 months old (n = 8), with complete atrio-ventricular dissociation and beta-adrenergic blockade. They were paced in the control period at a frequency of 120 beats . min-1. Both adults and puppies showed maximum action potential duration at a test pulse interval of over 700 ms. Below this the adult dogs showed a progressive shortening of the action potential duration (mean APD 81.5% at 200 ms). In contrast, the puppies showed much less shortening (91% at 200 ms; p less than 0.001). Measurements of Na+, K+-ATPase activity by the Rb uptake method gave values of 13.4 +/- 1.3 (puppies, n = 4) and 6.1 +/- 1.1 (adults, n = 6). These results may be consistent with the idea of a greater influx and efflux of sodium in the myocardial cells of the puppy compared with the adult dog.

Action Potentials↗
PubMed1978

Familial reinclusion of permanent molars.

Reinclusion of permanent molars was found in 55 individuals from 9 families. Inheritance is clearly autosomal dominant with complete penetrance. The provisional assignment of its gene locus to the same linkage group as the gene locus of blood group P (Bosker & Nijenhuis 1975) could not be confirmed.

Adolescent↗
PubMed1977

Visor osteotomy and vestibuloplasty--a one-stage procedure. A preliminary report.

The visor osteotomy as described by HARLE gives a considerable increase of the absolute height of the atrophic mandible, between the mental foramina. After 6 weeks a total vestibuloplasty with mucosal grafting (and a lowering of the floor of the mouth) is performed. A method is described in which the visor osteotomy and the vestibuloplasty are performed in one stage.

Atrophy↗
PubMed1977

Treatment of mandibular fractures by means of stable internal wire fixation.

Treatment according to the principles of stable internal fixation offers great advantages for fractures of the mandibular body. Most authors believe that a stable internal fixation can be achieved only by means of bone plating or screw fixation. At Groningen a wire connection was designed by BRONS which could be considered to be stable. The application of this stable internal wire fixation and the results of treatment in 272 fractures of the mandibular body between 1967 and 1976 are discussed.

Fracture Fixation, Internal↗
PubMed1977

Operative treatment of arthrosis deformans of the temporomandibular joint: a preliminary report.

If patients with arthrosis deformans of the temporomandibular joint are treated without success by conservative means, operative therapy may be indicated. The type of operation depends on the complaints: a)resection of the auriculotemporal nerve and superficial temporal artery; or b) the same operation in combination with condylar shaving. Twenty-four joints in 14 patients underwent a denervation. Thirty joints in 19 patients were also shaved. The results were very satisfactory.

Arthritis, Rheumatoid↗