Michael S. Block

Simultaneous maxillary sinus floor bone grafting and placement of hydroxylapatite-coated implants

This article outlines the treatment planning, surgical technique, and experiences with patients requiring maxillary sinus floor elevation for simultaneous autogenous bone grafting and placement of hydroxylapatite-coated dental implants. The results of six cases followed for up to 4 years are described.

Sinus augmentation for dental implants: the use of autogenous bone.

Autogenous bone has been the material of choice at our institution since 1983. The criteria for a successful graft in the sinus have been fulfilled based on functional stability in patients followed-up over 10 years in selected cases. Of 173 implants placed into autogenous bone grafted sinuses, 20 have been lost in four patients. Long-term follow-up is recommended for all graft materials used to support posterior maxillary restorations.

Mandibular alveolar ridge augmentation in the dog using distraction osteogenesis

PURPOSE This study investigated the use of distraction osteogenesis for alveolar ridge augmentation. MATERIALS AND METHODS Four dogs each had two superior and two inferior implants placed horizontally into an edentulous mandibular quadrant and, after integration, a distraction device was applied. An osteotomy was made to allow the ridge to be distracted vertically. After 10 mm vertical distraction, the device was stabilized. RESULTS The vertical augmentation averaged 8.85 +/- 1.05 mm after 10 weeks of healing. Serial sections showed that bone had formed between the distracted segments, creating an augmented ridge. CONCLUSIONS Distraction osteogenesis has the potential for use in augmentation of the alveolar ridge.

Evaluation of hydroxylapatite-coated titanium dental implants in dogs

The endosseous implant design and surgical technique of Branemark et al. have resulted in longterm success of prosthetic rehabilitations.’ When titanium implants are submerged in bone for three to four months before loaded, close proximity of bone to the implant surface develops. Although absence of an intervening fibrous tissue seam is observed,’ direct chemical bonding of bone to titanium has not been shown.* However, it has been shown that dense, nonresorbable. nonporous hydroxylapatite (HA) can bond directly to bone.3 This study compares the histologic response to a HAcoated titanium implant with that of two types of uncoated titanium endosseous dental implants in dogs.

Use of distraction osteogenesis for maxillary advancement: Preliminary results

In this pilot study, the principle of distraction osteogenesis to advance the anterior maxilla of the dog was used. After an anterior maxillary osteotomy, the anterior segment was advanced 10 mm in 10 days. Soft and hard tissue formation resulted in complete healing across the distraction gap without a soft tissue defect.

Factors associated with soft- and hard-tissue compromise of endosseous implants.

This prospective analysis identifies factors associated with endosseous implant removal as well as factors associated with implant morbidity resulting in nonscheduled patient visits. Treatment of the latter conditions is discussed. The most important factors identified for implant success were surgery without compromise in technique, placing implants into sound bone, avoiding thin bone or implant dehiscence at the time of implant placement, avoiding premature implant exposure during the healing period, establishing a balanced restoration, and insuring appropriate follow-up hygiene care. In the posterior mandible, the presence of keratinized gingiva was strongly correlated with optimal soft- and hard-tissue health.

Changes in the inferior alveolar nerve following mandibular lengthening in the dog using distraction osteogenesis

Distraction osteogenesis as per Ilizarov was used to lengthen the canine mandible. In this study, physiological and ultrastructural examination of the inferior nerve was performed. Mandibular body corticotomies were performed, and the mandible was distracted 7 mm. The animals were killed 4 weeks after the distraction was completed. Bone formed within the distraction gap in all dogs. There was no statistically significant difference in the jaw-jerk voltage between control and experimental sides. There was a significant difference between the distracted and control nerves in only one area of one nerve.

Prospective Evaluation of Immediate and Delayed Provisional Single Tooth Restorations

PURPOSE The purpose of this study was 2-fold: to determine whether there is a significant difference in the hard and soft tissue response comparing immediate with delayed implant placement after tooth removal, with immediate provisionalization, in maxillary anterior sites; and to determine and compare the crestal bone levels as the primary endpoint variable for implants placed and immediately temporized in extraction sites, to implants placed into extraction sites after the extraction site has been grafted and healed for 4 months, all immediately restored with an anatomic provisional restoration. This aim was to be evaluated by measuring crestal bone levels on standardized digital radiographs of the implants, using implant threads as a monitor of magnification and a pre-extraction reference. Secondary endpoint variables include soft tissue measures compared with method. MATERIALS AND METHODS A total of 76 patients were recruited and randomized into treatment groups. Group 1 had a maxillary tooth (premolar, canine, lateral or central incisor) removed, with immediate socket grafting, followed by implant placement and provisionalization 4 months later with a single tooth. Group 2 had immediate implant placement and provisionalization. Standardized radiograph holders were used to expose digital radiographs every 6 months from baseline to up to 2 years restored. Soft tissue measures were made from standardized reference points. Data collected were analyzed by a statistician to test the hypotheses. RESULTS A total of 55 patients completed their follow-up. Twenty-one patients were lost to follow-up because of implant loss (n = 5), 1 treated out of protocol because of labial bone loss found at the time of tooth removal (n = 1), geographic relocation (n = 11), dropped for noncompliance (n = 3), or medical problems (n = 1). The analyses showed no significant differences between groups in implant integration or crestal interdental bone movement on either the implant or the adjacent tooth. The bone level on the implants did move from the baseline levels during the first 6 months but not thereafter. There were no differences (P > .05) observed when comparing the interactions between groups, tooth locations, or time. There was a significant (P < .05) difference in the position of the facial gingival margin with a more apical position of the facial gingival margin in the delayed group compared with the immediate group during the course of the study. CONCLUSIONS Crestal bone response to immediate or delayed placement of an implant into an extraction site in the maxillary anterior region with immediate provisionalization is similar regarding hard tissue changes. Support of the gingival margin with a provisional at the time of tooth extraction and implant placement preserved 1 mm more facial gingival margin position compared with the delayed group. The decision to use either method must consider the movement of the facial gingival margin, which, in a critical esthetic patient may require soft tissue support from a provisional restoration or similar type of anatomical healing abutment.

Placement of endosseous implants into tooth extraction sites

This study reports 4-year experiences with placement of hydroxylapatite-coated dental implants into extraction sites immediately after tooth extraction. Small defects present after implant placement were treated with dense, nonresorbable hydroxylapatite. Larger defects present after implant placement were treated with demineralized bone. Indications and contraindications for placement, as well as surgical techniques, are discussed.

Anterior maxillary advancement using tooth-supported distraction osteogenesis

PURPOSE This study used the principle of distraction osteogenesis to advance the anterior maxilla of the dog using a totally tooth-supported distraction device. MATERIALS AND METHODS After an anterior maxillary osteotomy, the distraction device was activated 0.5 mm every 12 hours to advance the anterior segment 10 mm in 10 days. RESULTS Serial tooth and radiographic measurements indicated that on the 10th day the average tooth advancement was 8.4 mm +/- 1.5 mm and the average skeletal advancement was 4.0 mm +/- 1.5 mm. After 6 weeks the average tooth advancement was 7.2 +/- 1.6 mm and the average skeletal advancement was 3 +/- 1.3 mm. At 3 months the tooth advancement was 6.2 +/- 1.5 mm and at 6 months the tooth advancement was 5.0 +/- 1.1 mm. Bone healing was present in all animals. CONCLUSION This results of this study indicate that a tooth-borne maxillary distraction device will result in significantly greater dental movement than skeletal movement and that skeletal fixation may be needed for appliances used to advance the maxilla.