DISCUSSION.
Patients with highly compromised situations may have either an open bite, inadequate axial inclination of the implant crown, or poor treatment planning. Prosthodontic treatment using endosseous osseointegrating dental implants has proven to be a successful treatment method for complete and partially edentulous patients. The severe or inadequate angulation of an implant is a common problem in implant treatment. The inadequate angulation of the implant is inevitable in many cases. The following common causes of this problem must be considered:

1. inadequate surgery not using the surgical template;
2. placing the implant to get the maximum intrabony fixation not considering the final shape of the prosthesis;
3. inadequate angulation and shape of remaining alveolar bone with missing parts of alveolar process in the case of tooth and alveolar bone trauma;
4. anatomical structures such as mandibular nerve and maxillary sinus;
5. the shape and position of the jaw; and
6. the occurrence of the oroantral fistula.

The angulation of the implant site should be checked carefully with direction indicators throughout the drilling sequence in relation to the surgical template and the opposing jaw/dentition. The angulations should be checked from different views (eg, buccal and occlusal).
Inadequately placed implants may result in poorly contoured restorations, labial or incisal access hole location, improper prosthetic design, and biomechanical problems. Adequate diagnosis, treatment plan, and meticulous surgery should be performed to prevent these inadequate angulation cases.
Maxillary implants are rarely placed in the direction of the occlusal forces. After tooth loss, the bone is resorbed from the labial aspect first, and labial concavities are often present in this region. Therefore, the implant apex must be placed with a palatal angulation. This anatomical configuration affects the implant angulation and the final treatment plan.
Implants that are angled too far labially can result in placement of screw-access holes through the labial or buccal surfaces of the replacement teeth. Angulated abutments or mesostructures may be necessary for proper placement of screwaccess holes. These implants may even have to be buried to avoid irritation of the movable mucosa with resultant mucosal hyperplasia. Implants that are angled too far lingually can irritate the free mucosa of the mouth floor and cause difficulty with hygiene procedures. In the anterior maxilla, palatally placed implants may interfere with tongue function during speech. In the posterior molar area, a bending moment relative to the implant is created by lateral force, and bending has been demonstrated to produce a poorer distribution of the stresses to the implant and peri-implant bone than an axial load. Bending overload can be prevented by controlling the forces applied to the implants and by obtaining axial implant loading.
Inadequately placed implants have been managed by overcontouring the porcelain and by using angled abutment, custom fabricated abutment, double casting, or overlay casting, screw-retained crown, long crown, secondary bone or soft tissue graft, and additional implants. Maxillary surgical implant repositioning is a reliable, pre dictable method of correcting implants that are malpositioned vertically, anteroposteriorly, transversely, or axially. An implant should be placed to provide for mechanical loading down the long axis of the implant body to the maximum extent possible.4 Bell and Levy reported that an osteotomy was to be performed 5 mm away from the tooth apices to ensure and maintain blood supply with positive pulp tests at six months after surgery. The following are the precautions for surgery: minimal periosteal elevation of the segment, copious irrigation to avoid bone overheating, fixation of the segment, avoidance of intranasal and sinus pressure buildup by having the patient not blow their nose, and keeping the mouth open when sneezing for a period of one month.
From the results of this case, the procedure of the implant segmental osteotomy using the microplate may be recommended for use in association with the immediate correction of an inadequately placed endosseous implant. Continued follow-up is needed to assess the results obtained from using this procedure. Maintenance is an aspect of care that is commonly overlooked but cannot be overstressed.
Fixation of the segment after maxillary or mandibular osteotomies is carried out with microplates and microscrews. A four- to six-month bone healing period has been adequate after osteotomies. However, if any movement of the segment occurs after this period, a longer period (6–8 weeks) of immobilization is indicated and the occlusion should be checked to eliminate any premature contact.
In summary, the best treatment for malpositioned implants is the prevention of their occurrence. To place ideal orientation of the implant, the most important factor is good treatment planning. The successful outcome begins with clearly understood communication between the oral surgeon and the restoration dentist.

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