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The retentive part of parapulpal pins is often very bulky, and this may compromise the strength of the amalgam restoration. This in turn may considerably limit the range of applications of parapulpal pins. For this reason the geometry of the retentive pin portion was optimized with the aid of a finite element analysis. This manoeuvre resulted in a better stress distribution and improved retention, although the pin size was reduced. In clinical terms this implies a wider range of possible applications, because these pins allow safe anchorage of extensive amalgam restorations and do not affect the strength of the restoration.

Titanium-plasma-flame-spray coated endodontic stabilizers have been implanted in six patients after apicectomy. These endodontic stabilized teeth have been postoperatively under physiological stress. Histologically in one case there was six month post-operatively bone in direct contact to the implant surface and in certain areas the structure of a new periodontal membrane was formed.

The range of indications for amalgam includes class I cavities, when the occlusal carious lesions do not permit "extended fissure sealing," and similar class II cavities. Amalgam is not usable for class III and IV cavities in visible areas of the anterior teeth for aesthetic reasons. The standard rules for the class V preparation are also unreservedly valid for the preferred use of composite filling materials. Cervical lesions are not treatable according to the principles of adhesive restoration, or only as an exception. The construction of amalgam crowns represents an attempt at temporary restoration. Inlays, onlays, or crowns are the best methods of treating larger defects.

A clinical follow-up of 238 patients confirmed the good results of root amputation with titanium pin for apical closure. An analysis of reoperations because of failure of primary surgery rendered similarly good results. Therefore the use of a titanium pin will not impair the success of secondary surgery for root amputation which shows good results most of the time anyway.

According to our in vitro experiments, a combination of caustic acid and the brush technique with peripulpar screw dowels appears to be the method to be recommended for the optimal plastic build up of anterior teeth.

The use of implants in bone represents an extension of prosthetic possibilities. Clinical cases are used to demonstrate how additional supports can be created by means of implants of Linkow-blades which allow the incorporation of periodontally damaged teeth into prosthetic care. In addition the use of transdental fixation in the stabilisation of badly loosened teeth is pointed out.

A new procedure for apical closure after apical root resection with a metal filling is presented which is easy to handle with appropriately standardized equipment and ensures exact apical closure. By conical preparation of the whole root, a standardized metal peg which resists distortion can be used for anchoring the crown prosthesis without further preparation. Temporarily a standardized guttapercha peg can be used for closure. Even if renewed work on the root becomes necessary later, the apical metal closure remains firm because of its wedging.

The recommendation to use pin implants as fixing elements in horizontally fractured roots of anterior teeth is based on our own animal experiments as well as on clinical and radiological examinations of six patients. The examinations were made in 14 anterior teeth fixed to the bone by a pin the roots of which had been reduced to about half the physiologic length by resorption, amputation or fracture. The original biomechanical situation was the same in all three types of root reduction. We observed the pin-fixed teeth for 2 1/2 years on the average.

A combined light and scanning electron microscopic study in human molars examined the effects of seven different parapulpal screw systems on dentin structure. Dentin changes were systematically categorized into four different groups occurring alone or in combinations. Based on these observations a less traumatic screw system must be postulated. The assessment of a modified system demonstrated a considerable reduction of dentin lesions.

Transdental fixation, as closed implant, offers the most favourable preconditions of all dental procedures of implantation. Teeth where the root-crown relation is altered to the detriment of root length, which is held firm in bone, can with its help be made functional. Loosening and premature loss of teeth can be prevented. Further discussed is the indication for this procedure, especially in tooth fractures and luxations as well as the operative steps. Up to now transdental fixation has proved itself although the number of cases and the follow-up time are insufficient to allow final judgment.

Comparative tests of stress exerted on dowel constructions with secondarily attached crowns were carried out in 60 plastic roots. With one half of the roots, the final preparation was first determined after the dowel construction was inserted; a circular shoulder was uniformly sunk. The margin of the crown and the dowel construction therefore were not at the same level. The remaining half was not reprepared; the margin of the crown and dowel construction were at the same level. The test teeth were loaded palatally as far as the fracture. Most fractures were characteristic oblique fractures in the region of the gingiva. The differences between the two groups were impressive. The load capacity for constructions with level crown margins and dowel constructions as far as the fracture was 6 kp less in the middle than those not at the same level.

Following earlier studies on corrosion of silver pins in the root canal experience will be presented with the use of high-karat gold pins for apical closure of root amputations. The commercially available standardized Ackermann silver pins were replaced by high-karat gold pins of similar Vicker hardness and inserted in 218 patients with 264 root amputations since 1986. A clinical and radiological follow-up demonstrated a success rate of over 90%.

If temporary crowns are lost following preparation in the supporting areas, the condyles may be displaced. It however was established that the normal position of the condyles can be approximately reproduced with a central bearing device. On the basis of the results, it was determined that the support pin method is superior to the procedure using central wax registration.

Pathologically movable anteriors with horizontal root fracture can be fixed by endodontal bone pins, unless the fracture is located in the cervical third of the root canal. The apical root fragment needs to be removed for fixation. As the anatomic conditions in monkeys do not permit adequate preparation of the root canal required for endodontal pin fixation, the histological findings can be transferred to man to a limited extent only.