The use of Immediate Loading Protocol for Replacement of Missing Mandibular Anterior Teeth with Narrow Available Bone Width: A Clinical Report

INTRODUCTION

Tooth replacement with a dental implant has proven to be a reliable and effective method of restoring edentulous dentition. Traditional dental implant placement protocols required preparation of the surgical site to establish intimate contact of the implant with the alveolar bone¹. After tooth extraction, a 6-month healing period was recommended to allow bone to fill in the extraction socket before implant placement. In addition, a subsequent healing period of 3−6 months after fixture placement was indicated. This protocol could leave patients without teeth or with an uncomfortable temporary prosthesis for a long time during implant therapy². In recent decades, implant treatment protocols have been challenged, and new approaches aim to shorten the overall treatment period as follows:

1) immediate implant placement in extraction sockets;

2) immediate restoration following implant placement;

3) immediate implant restoration in extraction sockets; and

4) immediate implant restoration and immediate tissue reconstruction.

The aim of this article is to describe a clinical condition where implants were immediately loaded to rehabilitate esthetics and function.

CASE REPORT

A 32 year old female patient presented with partially edentulous mandibular condition involving missing lower anterior teeth and first premolars. The patient's medical history was noncontributory. The patient was informed that her restorative options included a removable partial denture, a fixed bridge, and a fixed implant restoration. In order to avoid damaging the adjacent teeth, a fixed implant restoration was selected by the patient.

Clinical examination revealed a Seibert's Class III ridge condition (loss of both width and height of the ridge)³. Radiological evaluation revealed divison B-w bone condition 4 according to Misch's classification for available bone⁴. The available bone width for implant placement was approximately 3mm based on bone sounding in most of the edentulous region. Some amount of ridge expansion was required for placement of implant. The treatment plan included placement of single piece narrow diameter implants (Aeropress, Alpha-Bio) in relation to 33,31,41,43 region and to load them immediately with tooth coloured provisional six unit bridge to rehabilitate both esthetics and function of the patient. The placement of a 1-piece aeropress implant with an incorporated prosthetic abutment simplifies the prosthetic management of such a patient. The 1-piece implant has a tapered root form with a fixed abutment as an integral part of the implant. Thus, there is no microgap between the implant and the abutment that could harbor bacteria nor is there a need to change healing caps or cover screws for abutments at the implant level after implant integration. Also, the narrow diameter at the tip allows placement of implant in extremely narrow ridges with gradual expansion of bone as the implant is screwed into the osteotomy hole⁵.

A clear acrylic resin surgical stent was prepared on the diagnostic cast with the small steel balls of known diameter placed over the proposed implant site. A second OPG was made with stent in the patient mouth to assess the height of the available bone accurately. Later in the same stent the steel balls were removed and the resultant holes were used as a surgical guide during implant placement.

Under local anesthesia, mucoperiosteal flap was reflected and with the help of surgical stent, four endosseous implants (single piece, Aeropress implants, Alpha Bio) were placed. Implants measuring: 3.1 mm x 13mm in incisor region and 3.1mm x 11mm for canine-premolar region were placed at the proposed implant sites .The surgery was uneventful. The primary stability of the implants was excellent which a prerequisite for immediate loading is. A new design for provisional restoration was formulated by addition of both buccal and lingual clasp like acrylic extensions on adjacent natural teeth. This was to avoid any undesirable lateral forces on implants during healing. So the implant was loaded immediately, but only to the axial load.

The patient was instructed to avoid any function of the implant for 6 weeks. The provisional restoration was left undisturbed for 3 months. The implant integration was evaluated both clinically and radiographically before making the definitive impression (Xpress XT; 3M ESPE, St. Paul, Minn) using a closed-tray impression technique. Two definitive metal ceramic three unit bridges were fabricated in relation to implants placed in canine and central incisor region bilaterally. Mutually protected occlusion scheme was provided. The final prostheses were cemented using glass ionomer luting cement giving the patient a boost in self esteem and psychological comfort. The evaluation at 9 months showed a good esthetic result along with patient satisfaction.

SUMMARY

With careful patient selection and precise treatment planning, different strategies of immediate implant placement and/or immediate restoration have shown promising results in providing reconstruction of the dentoalveolar complex in a [1] one stage approach . These protocols benefit patients by reducing surgical procedures and the healing period, decreasing the time when they are toothless, and increasing patient acceptance of dental rehabilitation following tooth extraction. The replacement of six missing lower anterior teeth with 4 single-piece implant was accomplished in minimum time, with a stable, functional, and esthetic result and little discomfort to the patient.