Tenting Abutment Technique Versus Screw"Tent-Pole" Technique for Augmentation of Posterior Atrophic Mandible

To evaluate a novel method using a designed tenting abutment to reduce number of surgeries and the edentulous healing period is shortened. In addition, to prevent vertical and horizontal collapse of the bone graft and minimizes resorption of the bone graft during the healing the atrophic posterior mandible.

The tent pole provides excellent mechanical properties; stability \& fixation, yet very poor features to preserve the integrity of the soft tissue.

Using the tenting abutment technique will help preserve the soft tissue and decrease the amount of dehiscence that might accompany the use of the tent pole.

Augmentation of insufficient bone volume can be brought about by different methods, including, particulate and block grafting materials, guided Bone Regeneration with or without growth and differentiation factors, ridge splitting, expansion and distraction osteogenesis, either alone or in combination. These techniques may be used for horizontal/vertical ridge augmentation.

Xenograft bone has been utilized for the reconstruction of large 3-dimensional defects because it has no donor site morbidity and is of an unlimited volume in quantity.

Guided bone regeneration (GBR) describes the use of membranes to regenerate bony defects. A membrane for GBR needs to be biocompatible, cell occlusive, non-toxic, moldable and possess space-maintaining properties including stability.

* e. Explanation for choice of comparators (conventional titanium mesh): Tent pole offers superb mechanical properties for guided bone regeneration treatment in larger areas and it is regarded one of the most available covers for guided bone regeneration yet one of the cheapest.

  B. Objectives:
* a. Aim of the study:

  * To evaluate the quantity of gained bone under tenting abutment compared to a tent pole.
  * To evaluate amount of wound dehiscence postoperatively using tenting abutment technique compared to a tent pole.
  * ·To optimize the anatomical situation in order to facilitate implant installation.

7b. Hypothesis:

* Bone is a dynamic and living tissue with the capacity to repair and regenerate in response to injury. It is further possible to guide bone cells into an area that previously consisted of bony tissue to regenerate bone and increase the bone volume.
* Tenting abutment is suitable as a biomaterial for creating a space between the bone cortex and the periosteum to enhance new bone regeneration.
* Tenting abutment material will enhance the quantity and quality of newly formed bone.
* Tenting abutment will cause less soft tissue dehiscence and will dramatically decrease the percentage of the collapse of the space produced by the bone graft and minimizes resorption of the grafting material compared to the titanium mesh.

  7c. Primary and secondary objectives:
  1. Primary objective:

     Evaluate bone gained (height and width) and the period of time of healing in the atrophic posterior mandible when using tenting abutment technique compared to tent pole.
  2. Secondary objectives:

Evaluation of soft tissue dehiscence and resorption of the grafting material that might occur using tent pole compared to the tenting abutment.

Eligibility Criteria:
Inclusion Criteria:

* Patients with atrophic posterior mandible.
* Both sexes.
* No intraoral soft and hard tissue pathology.
* No systemic condition that contraindicates implant placement

Exclusion Criteria:

* Local criteria:

  * Untreated gingivitis, periodontitis.
  * Insufficient oral hygiene.
  * Previous radiation therapy for the head and neck neoplasia, or bone augmentation to implant site..

Systemic criteria:

* Systemic disorders.
* Heavy smoking of more than 20 cigarettes per day.
* Bone pathology.
* ·Psychiatric problems. Emotional instability. Unrealistic aesthetic demands.