The edentulous ridge expansion (ERE) technique an experimental study in the dog

Objective: To compare the healing and bony crest resorption at implants installed conventionally or applying an edentulous ridge expansion (ERE) technique in the maxilla.Material and methods: In six Labrador dogs, the first and second maxillary incisors were extracted bilaterally. In the left side of the maxilla (Test), the flaps were elevated and the buccal plate of the alveoli and septa was removed. After 3 months of healing, partial-thickness (split) flaps were dissected and the residual alveolar bone was exposed. In the right side of the maxilla, an implant was installed conventionally (Type IV; Control) while, in the left side, the ERE technique was adopted. Hence, an expansion of the buccal bony crest was obtained, and the implant was subsequently installed (Test). After 3 months of healing, biopsies were obtained and ground sections were prepared for histological analyses.Results: A buccal vertical resorption of the bony crest of 2.2 +/- 1.2 mm and 1.6 +/- 0.7 mm was found at the test and control sites, respectively. The difference, however, did not reach statistical significance. The coronal level of osseointegration at the buccal aspect was located at 3.1 +/- 1.0 mm and 2.2 +/- 0.7 mm from the implant shoulder at the test and control sites, respectively, the difference being statistically significant. The mean values of the mineralized bone-to-implant contact (MBIC%) ranged from 43% to 48% at the buccal and lingual sites. No differences reached statistical significance.Conclusions: Implants installed by applying an ERE technique may osseointegrate similarly to conventional implant installation. However, vertical and horizontal resorption of the displaced buccal bony wall occurred as well.

Influence on alveolar resorption of the buccal bony plate width in the edentulous ridge expansion (ERE) - an experimental study in the dog

Objective: To compare the hard tissue changes at implants installed applying edentulous ridge expansion (E.R.E.) at sites with a buccal bony wall thickness of 1 or 2 mm.Material and methods: In six Labrador dogs, the first and second maxillary incisors were extracted, and the buccal alveolar bony plates and septa were removed. After 3 months of healing, partial-thickness flaps were dissected, and the E.R.E. was applied bilaterally. Hence, an expansion of the buccal bony crest was obtained in both sides of the maxilla with a displacement of either a 1- or a 2-mm-wide buccal bony plate at the test and control sites, respectively. After 3 months of healing, biopsies were obtained for histological analyses.Results: A buccal vertical resorption of the alveolar crest of 2.3 +/- 0.8 and 2.1 +/- 1.1 mm, and a coronal level of osseointegration at the buccal aspect of 2.7 +/- 0.5 and 2.9 +/- 0.9 mm were found at the test (1 mm) and control (2 mm) sites, respectively. The differences did not reach statistical significance. The mean values of the mineralized bone-to-implant contact (MBIC%) ranged from 62% to 73% at the buccal and lingual sites. No statistically significant differences were found. Horizontal volume gains of 1.8 and 1.1 mm were observed at the test and control sites, respectively, and the difference being statistically significant.Conclusions: Implants installed using the E.R.E. technique yielded a high degree of osseointegration. It is suggested that the displacement of buccal bony plates of 1 mm thickness is preferable compared with that of wider dimensions.

Implant removal by means of an expansion of the alveolar bony crest: Report of a clinical technique

Aim: To describe the adaptation of the Edentulous Ridge Expansion (E.R.E.) technique for implant removal. Material and Methods: The E.R.E. technique for the removal of failed implants is described in detail. A clinical case is also reported. In a patient carrying a full arch removable prosthesis in the upper jaw, sustained by two bars, two out of five implants were found to be fractured. Bucco-lingual partial-thickness flaps were used to access the fractured implants. The implants were subsequently removed applying the E.R.E. technique. Two recipient sites were prepared in the same position, using bone expanders, and two new implants were installed. Results: After 4 months of healing, the implants were integrated and a new bar was fabricated, and the old prosthesis readapted. Conclusion: The ERE technique may be successfully applied for the removal of failed implants, and the immediate or delayed reinstallation of new implants. © 2012 John Wiley & Sons A/S.

BONE SPREADER TECHNIQUE: A PRELIMINARY 3-YEAR STUDY

The purpose of this study was to observe the clinical outcome of bone spreading and standardized dilation of horizontally resorbed bone during immediate implant placement using a "screw-type" configuration of expansion and threadformers. Fifty-three patients were included in this study, and 41 edentulous areas in anterior and posterior maxillas were treated. Sixty-eight implants were placed using an insertion torque of at least 40 Ncm. Abutments were delivered 4 to 6 months after implant placement. The overall failure percentage was 4.41% (3 failures). A retrieved analysis of I implant removed at 3 years after placement demonstrated bone resorption down to the level of the third thread. The bone spreader technique is different from Summers' osteotome, both in clinical use and in armamentarium. The main advantage of the crest-expanding technique is that it is a less invasive procedure; the facial wall expands after the medullary bone is compressed against the cortical wall. Within the limits of this preliminary study, the cumulative survival rate for this method of implant placement is 95.58% at 3 years. This study confirms that a bone spreader used in the maxilla shows an unusually low failure rate after 3 years.

Bone Spreading and Standardized Dilation of Horizontally Resorbed Bone: Technical Considerations

The uses of a new bone spreading technique with simultaneous implant placement are discussed. The spreading system is an alternative technique to Summers' osteotome. Specific screw designs (spreader) served to laterally compress the bone to increase the cancellous density adjacent to the site. The spreader achieved a controlled and standardized dilation of horizontal bone. The advantages, material selection, and the application of this new procedure are detailed. (Implant Dent 2009; 18:119-125)

Evaluation of Stress Patterns Produced by Implant-Retained Overdentures and Implant-Retained Fixed Partial Denture

The purposes of this study were to photoelastically measure the biomechanical behavior of 4 implants retaining different cantilevered bar mandibular overdenture designs and to compare a fixed partial denture (FPD). A photoelastic model of a human edentulous mandible was fabricated, which contained 4 screw-type implants (3.75 x 10 mm) embedded in the parasymphyseal area. An FPD and 3 overdenture designs with the following attachments were evaluated: 3 plastic Hader clips, 1 Hader clip with 2 posterior resilient cap attachments, and 3 ball/O-ring attachments. Vertical occlusal forces of 100 N were applied between the central incisor and unilaterally to the right and left second premolars and second molars. Stresses that developed in the supporting structure were monitored photoelastically and recorded photographically. The results showed that the anterior loading, the overdenture with 3 plastic Hader clips, displayed the largest stress concentration at the medium implant. With premolar loading, the FPD and overdenture with 3 plastic Hader clips displayed the highest stresses to the ipsilateral terminal implant. With molar loading, the overdenture with 3 ball/O-ring attachments displayed the most uniform stress distribution in the posterior edentulous ridge, with less overloading in the terminal implant. It was concluded that vertical forces applied to the bar-clip overdenture and FPD created immediate stress patterns of greater magnitude and concentration on the ipsilateral implants, whereas the ball/O-ring attachments transferred minimal stress to the implants. The increased cantilever in the FPD caused the highest stresses to the terminal implant.

Tensile bond strengths of hard chairside reline resins as influenced by water storage

Due to gradual resorption of the edentulous ridge bone, removable prostheses often require denture base relines to improve fit and stability. This research evaluated the bond strength between one heat-cured acrylic resin (Lucitone 550®) and two hard chairside reline resins, after two different periods of storage in water (50 h and 30 days). The bond strength was evaluated using a tensile test. The mode of failure, adhesive or cohesive, was also recorded. The results submitted to the Kruskal-Wallis test indicated that the highest tensile strengths were achieved with intact Lucitone 550® denture base resin in both periods of storage in water. After 50 h of storage in water, Duraliner II® reline material exhibited the highest bond strength to the denture base resin. After 30 days of storage in water, Duraliner II® reline resin demonstrated a significant reduction in adhesion, showing lower tensile bond strength than Kooliner® material. Both hard chairside reline materials failed adhesively across Lucitone 550® denture base resin, in both periods of time. © 1999 Blackwell Science Ltd.

Enxerto de osso autógeno em neoformação associado ou não a barreira de tecido conjuntivo no tratamento de lesões de furca Classe II: estudo histológico e histométrico em cães

Pós-graduação em Odontologia - FOA

Avaliação fotoelástica de overdentures mandibulares sobre implantes com três diferentes sistemas de retenção e prótese protocolo de Branemark

Pós-graduação em Odontologia - FOA

Spontaneous osteonecrosis of the jaws in the maxilla of mice on antiresorptive treatment: A novel ONJ mouse model

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Flabby Ridge Correction Using an Auxiliary Technique With Connective Tissue Graft

A common finding in patients with edentulous maxilla and partially dentate mandible is mainly the presence of flabbiness in the anterior edentulous alveolar ridge that can compromise the retention and stability of a denture. Thus, this case report presents the correction of a flabby ridge, using an auxiliary technique combining surgical excision and autogenous connective tissue grafting. The technique improved the quality of the osteomucosal support of the alveolar ridge and increased the vestibule deepness, whose result increased the success rate of the new conventional total prosthesis.

Kinesiographic study of complete denture movement related to mucosa displacement in edentulous patients.

The mucosa that covers the residual ridges of edentulous patients may present some distortion or displacement when occlusal loading is applied in complete dentures. This distortion and movement of the denture can result in acceleration of residual ridge resorption and loss of retention and stability. The aim of this study was to analyze the pattern of upper complete denture movement related to underlying mucosa displacement. A sample of 10 complete denture wearers was randomly selected, which had acceptable upper and lower dentures and normal volume and resilience of residual ridges. The kinesiographic instrument K6-I Diagnostic System was used to measure denture movements, according to the method proposed by Maeda et al.7, 1984. Denture movements were measured under the following experimental conditions: (A) 3 maximum voluntary clenching cycles and (B) unilateral chewing for 20 seconds. The results showed that under physiological load, oral mucosa distortion has two distinct phases: a fast initial displacement as load is applied and a slower and incomplete recovery when load is removed. Intermittent loading such as chewing progressively reduces the magnitude of the denture displacement and the recovery of the mucosa is gradually more incomplete.

Fate of autologous and fresh-frozen allogeneic block bone grafts used for ridge augmentation. A CBCT-based analysis

Objectives: To evaluate dimensional changes in autologous (AT) and fresh-frozen allogeneic (AL) block bone grafts 6 months after alveolar ridge augmentation. Material and methods: Twenty-six partially or totally edentulous patients treated either with fresh-frozen AL bone or AT bone onlay block grafts prior to implant placement (13 patients in each group), were included in this analysis. Patients received CBCT (i-CAT Classic) examinations prior to surgery and 14 days and 6 months after grafting. Differences in alveolar ridge area among the various observation times were evaluated by planimetric measurements on two-dimensional CBCT images of the grafted regions. Nineteen grafted blocks from each group were evaluated. Results: Significant increase in alveolar ridge dimensions, allowing implant placement, was obtained with both types of grafts 6 months after grafting; no significant differences in alveolar ridge area were observed between the groups at the various observation times. However, graft resorption in the AL group was significantly larger compared to that in the AT group at 6 months. Conclusions: Larger bone graft resorption was seen in patients treated with fresh-frozen AL bone than in those treated with AT bone 6 months following alveolar ridge augmentation. © 2011 John Wiley & Sons A/S.

Immunological aspects of fresh-frozen allogeneic bone grafting for lateral ridge augmentation

Objectives: To present some immunological aspects of fresh-frozen allogeneic bone grafting for lateral bone augmentation, based on the quantitative evaluation of IL-10, IL-1β, IFN- γ and TNF- α in patients sera. Material and methods: Thirty-three partially or totally edentulous patients received fresh-frozen allogeneic bone (AL - 20 patients) or autologous bone onlay block grafts (AT - 13 patients) prior to oral implant placement. Blood samples were collected from each patient at various time-points during a 6 month-period (baseline, 14, 30, 90 and 180 days postoperatively). Quantitative evaluation of IL-10, IL-1β, IFN- γ and TNF- α was performed by enzyme linked immunosorbent assay (ELISA). Results: For all evaluated markers and at all evaluated periods, inter-group comparisons showed no statistically significant differences between the groups, while the observed values were within normal levels. For AL-treated patients, intra-group evaluation showed statistically significant increase of TNF-α from baseline to 90 (P < 0.001) and 180 (P < 0.01) days, and from 14 to 90 (P < 0.01) and 180 (P < 0.05) days. IFN- γ showed intercalated results, with a decrease from baseline to 14 days (P < 0.05), and increase from 14 to 90 days (P < 0.001) and 180 (P < 0.05) days. No differences between the periods of evaluation were found for the AT group. Conclusions: AL grafting for lateral bone augmentation, similar to AT grafting, does not seem to challenge the immune system significantly. © 2012 John Wiley & Sons A/S.

Horizontal ridge augmentation of the atrophic anterior maxilla using rhBMP-2/ACS or autogenous bone grafts: A proof-of-concept randomized clinical trial

Aim To compare the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge carrier (ACS) with autogenous bone graft for augmentation of the edentulous atrophic anterior maxilla. Methods Twenty-four subjects were enrolled in a randomized, controlled, parallel-group, open-label clinical trial. Subjects either received rhBMP-2/ACS (1.5 mg/ml) or particulated autogenous bone harvested from the mandibular retromolar region. A titanium-mesh was used to provide space and wound stability. A guide was used to standardize clinical recordings using an analogue caliper. Alveolar ridge width was also assessed using cone-beam computed tomography. Results rhBMP-2/ACS yielded significantly greater radiographic horizontal bone gain compared with autogenous bone graft at immediate subcrestal levels (1.5 ± 0.7 versus 0.5 ± 0.9 mm; p = 0.01); non-significant differences were observed at mid- (2.9 ± 0.8 versus 2.9 ± 0.9 mm; p = 0.98) and apical (1.7 ± 0.9 versus 1.8 ± 1.1 mm; p = 0.85) crestal levels. No significant differences in clinical horizontal bone gain were observed at 6 months between rhBMP-2/ACS and autogenous bone graft (3.2 ± 0.9 mm versus 3.7 ± 1.4 mm; p = 0.31). Sixty-two implants were placed after 6 month of healing with no significant differences between groups for number of implants, implant size, primary stability and survival. Conclusions rhBMP-2/ACS appears a realistic alternative for augmentation of the edentulous atrophic anterior maxilla. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.