Notas Breves

Long-term Results of Implants Treated with Guided Bone Regeneration: a 5-year Prospective Study (*)

The aim of this prospective 5-year longitudinal study was to follow endosteal implants in wich guided bone regeneration (GBR) was applied during implant placement. In 75 patients, defects around implants (Brånemark System) were treated with Bio-Oss and Bio-Gide (112 implants). In split-mouth patients in this group, Bio-Oss and Gore-Tex were used in the second defect site (41 implants). All 75 patients had at least 1 implant that was entirely surrounded by bone and served as the control (112 implants). After placement of the definitive prostheses (single-tooth, fixed, or removable implant prostheses), patients were recalled after 6 months and then every 12 months during a 5-year observation period.
The following variables were investigated: implant survival, marginal bone level (MBL), prescence of plaque, peri-implant mucosal conditions, height of keratinized mucosa (KM), and marginal soft tissue level (MSTL). The cumulative implant survival rate after 5 years varied between 93% and 97% for implants treated with or without GBR. The mean MBL after 60 months was 1.83 mm for sites treated with Bio-Oss and Bio-Gide, 2.21 mm for sites treated with Bio-Oss and Gore-Tex, and 1.73 mm for the control sites. The MBL values were found to increase significantly with time and differed significantly among the treatment groups. During the observation period, KM varied between 3.16 and 3.02 mm. A slight recession of 0.1 mm was observed, and plaque was found in 15% of all sites and was associated with inflammatory symptoms of the peri-implant mucosa. It was observed that such symptoms and recession correlated more strongly with the type of restoration than with the type of treatment. This study demonstrated that implants placed with or without GBR techniques had similar survival rates after 5 years, but that bone resorption was more pronounced in sites with GBR treatment. It was assumed that the use of GBR is indeed indicated when the initial defect size is larger than 2 mm in the vertical dimension.

	Clinical situation during implant placement in the maxilla with exposed implant surfaces to be treated with GBR.
	Re-entry of the same site, with elevated flap for assessment of the former defects.
	Radiographs at 12 months observation.
	Same patient at 60 months observation.

Key words: bone level, dental implants, guided bone regeneration, keratinized mucosa, marginal soft tissue level.

Nicola Ursula Zitzmann, Dr. Med. Dent
Peter Schärer, Prof. Dr. Med. Dent, MS
Carlo Paolo Marinello, Prof. Dr. Med. Dent, MS

(*) Extraido de la revista "The International Journal of ORAL & MAXILLOFACIAL IMPLANTS" - 2001;16:355-366

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Ridge Augmentation Using Mandibular Block Bone Grafts: Preliminary Results of an Ongoing Prospective Study (*)

The aim of the current ongoing study is to evaluate the long-term results of endosseous implants placed into autogenous bone grafts from intraoral donor sites. Patient selection for the correction of bone deficiencies was based on biomechanical and esthetic needs. Donor site selection was dependent upon the type of deficiency and the graft shape needed. Two-stage implants were placed after a healing period of 3 to 6 months, based on an assessment of the graft viability with radiographic and clinical parameters. Thus far, 118 implants have been placed in 60 patients whose alveolar ridges were deficient in height, width, or both height and width and were augmented. The patients were observed for up to 77 months. Two implants failures were encountered before implant exposure (1.7%). No further implants have been lost in function.

	Labial view of cortical block graft from the ramus repairing a deficiency in width.
	Labial view of symphyseal block graft being used to augmented a deficiency in height. Additional stability was gained by the use of titanium bone plates.
	Occlusal view of bone graft reconstructing the alveolar ridge. The graft from the ramus is particulary suited for reconstruction of defects in width and height because of donor site morphology.
	Symphyseal donor site exposed via a full-thickness flap, made using a cervical incision, showing the graft prior to elevation. The superior cut, beveled to avoid the apices, was made more than 5 mm from the apices of the teeth.
	Retromolar donor site with graft outlined prior to elevation. The morphology of the external oblique ridge is particulary suited to augment a ridge deficient in height and width.
	Postoperative periapical radiograph used as a baseline reference. The sharp outline of the horizontal portion of the grafted cortical bone is visible.
	Periapical radiograph taken 3 months postoperatively. A more diffuse appearance of the cortex was considered to be indicative of metabolic activity.

Key words: alveolar ridge augmentation, autogenous bone graft, esthetics, intraoral donor sites, osseointegrated dental implants.

Ashok Sethi, BDS, DGDP, MGDSRCS, DUI
Thomas Kaus, Dr Med Dent

(*) Extraido de la revista "The International Journal of ORAL & MAXILLOFACIAL IMPLANTS" - 2001;16:378-388

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Development and Treatment of Retrograde Peri-implantitis Involving a Site with a History of Failed Endodontic and Apicoectomy Procedures: A Series of Reports (*)

Osseointegrated implants provide predictable restorative support for crowns, restorations, prosthesis abutments, and removable dentures. Their widespread use in recent years has produced different types of complications. Retrograde peri-implantitis, a lesion occurring at the periapical area of an osseointegrated implant, has recently been described. This paper presents a series of reports describing the occurrence and management of retrograde peri-implantitis involving implants replacing teeth with histories of failed endodontic and apicoectomy procedures.

	Patient 1. Note draining fistulous tract on the buccal attached tissue opposite the implant on area of the maxillary left first premolar.
	Patient 1. A periapical radiograph reveals a peri-implant radiolucency involving almost half the length of the implant.
	Patient 1. Flap elevation reveals what appears to be soft tissue in the area of the implant apex.
	Patient 1. A bony defect is apparent after curettage and removal of infected tissue.
	Patient 1. The bony defect and implant apex appear to be free of infected tissue after thorough debridement.
	Patient 1. Tetracycline paste is placed in the area for 1 minute.
	Patient 1. The area has been thoroughly rinsed and irrigated.
	Patient 1. Flap closure.
	Patient 1. Eigth months after treatment, partial resolution of the radiolucency can be noted.

	Patient 2. Note radiolucency surrounding the apical area of the implant.
	Patient 2. Periapical radiograph taken 8 months after surgery. Note partial resolution of the peri-implant radiolucency.

	Patient 3. A periapical radiograph reveals radiolucency around the apex of the implant.
	Patient 3. A radiograph taken 8 years after surgical treatment shows complete resolution of the peri-implant radiolucency.

Key words: apicoectomy, debridement, dental implants, endodontics, retrograde peri-implantitis, tetracycline.

Lilibeth Ayangco, DMD
Phillip J. Sheridan, DDS, MS

(*) Extraido de la revista "The International Journal of ORAL & MAXILLOFACIAL IMPLANTS" - 2001;16:412-417

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