Effects of different consolidation periods on bone formation and implant success in alveolar distraction osteogenesis: A clinical study

Indications and surgical technique for distraction osteogenesis of the alveolar bone for augmentation prior to insertion of dental implants

When bone is limited, short, ultra-short, or narrow implants help to restore oral rehabilitation with an acceptable long-term outcome. This becomes more difficult with severe vertical bone loss. Guided bone regeneration, onlay block transplantation, or sandwich osteotomy have been established to build up these defects. The alternative to the alveolar distraction osteogenesis (ADO) has only been established in some centers, with a standardized protocol. On the one hand, ADO is a biological procedure that allows almost a "restitutio ad integrum" when building up hard and soft tissue. On the other hand, there are clear indications, limitations, and complications of the procedure in the literature. In addition to the literature, concept of Tissue Regeneration by Alveolar Callusdistraction Cologne (TRACC), which has been practiced successfully for over two decades, will be presented for different indications.

Horizontal ridge augmentation using xenogenous bone graft-systematic review

PURPOSE

This study aimed to perform a systematic review about the use of xenogenous bonegraft in horizontal ridge augmentation to answer the following question: In implant patients, treated with xenografts for horizontal ridge augmentation, what would be the outcomes in terms of bone gain, bone resorption, implant survival, and complication rates?

METHODS

The main search was performed at PubMed, Cochrane, and Scopus databases, and found 2610 articles. After selection and duplicate removal, 29 studies were included in the final review. The collected data were sample size, number and type of graft, site, horizontal gain, resorption rate, and complications.

RESULTS

A total of 610 patients were submitted to 853 bone grafts, both in the maxilla and mandible. Most studies (n = 26) used particulate grafts, isolated or associated with autogenous bone, and covered by collagen membrane or titanium mesh. The mean of horizontal bone gain was 4.44 mm. In addition, the augmented ridges allowed placement of 1325 successful dental implants. The complication rate was 7.85%, and membrane exposure was the most reported complication.

CONCLUSIONS

Although the autogenous bone graft remains as the gold standard for alveolar reconstruction, this review suggests that xenogenous bone graft is a feasible alternative for horizontal bone augmentation.

Alveolar distraction osteogenesis for dental implant treatments of the vertical bone atrophy: A systematic review

BACKGROUND

To determine if alveolar vertical distraction osteogenesis obtains better results compared to other bone regeneration treatments (guided bone regeneration with membranes and / or filling material, or autogenous bone graft) in terms of bone gain, complications, and implant survival and success rates.

MATERIAL AND METHODS

An electronic search was performed in Pubmed (MEDLINE), Cochrane Library and Scopus databases in March 2017. Besides, a manual search was carried out. Inclusion criteria were randomized controlled trials published within the last 10 years with at least 1 year of follow-up after implant placement. No language restriction was applied. Exclusion criteria were studies in patients with bone defects produced by trauma, congenital malformation or oncologic surgical treatment. The methodological quality of the selected studies was evaluated by means of the Cochrane Collaboration's Tool for assessing risk of bias. The reports were classified into different levels of recommendation according to the "Strength of Recommendation Taxonomy ".

RESULTS

Out of 221 articles, two randomized controlled trials were finally selected for the inclusion in the systematic review. Bone gain and complications were higher with the alveolar vertical distraction osteogenesis compared to the autologous bone graft. There was higher bone resorption with the autologous bone graft. Implant survival and success rates were similar between studies, despite of the used technique.

CONCLUSIONS

Both alveolar distraction osteogenesis and autogenous bone graft are effective bone regeneration techniques for the treatment of mandibular vertical bone atrophy. A level B recommendation can be established for the use of alveolar vertical distraction osteogenesis for the treatment of the mandibular vertical bone atrophy.

Investigation of effects of low level laser therapy in distraction osteogenesis

PURPOSE

The purpose of the study was to investigate the histopathological effects of low level laser therapy (LLLT) application in distraction osteogenesis (DO).

MATERIALS AND METHODS

Twenty adult female New Zealand white rabbits were included in the study. Under general anesthesia unilateral mandibular corpus osteotomy was performed. Custom made external distractors were placed to right mandibles of rabbits. After five days of latency period, distractors were activated once a day for 5 days with 1mm/day frequency. Animals in the study group were exposed to LLLT from six different points transcutanously after each distractor activation. Control group was not exposed to laser irradiation. Animals were sacrificed after 15 and 30 days of consolidation periods and mandibles were processed for histopathological investigation under light microscope. Bone healing was analyzed with a semi-quantitative 4 point scale.

RESULTS

Osteoblastic activity and vascularization were found higher in the study group than control group after 15 days consolidation. Chondroblastic activity of the control group was significantly higher than the study group in both 15 and 30 days of consolidation groups. Osteoblastic activity and trabecular bone formation were found significantly higher in the study group than the control group after 15 days consolidation.

CONCLUSIONS

The use of LLLT in activation period of distraction osteogenesis stimulates bone repair in the early stages of distraction osteogenesis by inducing intramembranous healing and less cartilage tissue formation in the bone callus.

Rapid Anterior Segmental Maxillary Retraction by Compression Osteogenesis

Maxillary protrusion is one of the deformities of the upper jaw. Orthodontics and orthodontics combined with anterior segmental osteotomy are the common treatment strategies for this deformity. The hypothesis of this study was that the maxillary bone segment could be gradually moved backward safely by using a tooth-borne-specific compression device that causes bone compression at the bony segment interface after performance of surgical bone cuts in cases of anterior maxillary protrusion. Ten patients with skeletal maxillary protrusion were treated by modified subapical maxillary osteotomy. Then the protrusion was gradually set back and fixed in a new position through the use of a compression device. After 8 weeks, the device was removed, and soft and hard tissue was evaluated. The average setback of the anterior maxillary segment was found to be 6.8 mm. The ratio of the upper lip to the maxillary incisor retraction was 0.52:1. The nasolabial angle increased with a change of 13.5°. The mentolabial angle increased with a change of 12.5°. This study is the first clinical study in using compression osteogenesis aided by a modified anterior subapical maxillary osteotomy technique in the management of skeletal maxillary protrusion that considered as an alternative to traditional surgical methods and to avoid its complications. It can be used successfully and safely, leading to rapid maximum setback of the anterior maxillary segment with great contact between bone segment, better and gradual hard and soft tissue remodeling, short treatment duration, and avoid using plates and screws with its complications.

Unusual Spontaneous Mandibular Regeneration of a Large Defect Followed by Orthodontics, Alveolar Distraction, and Dental Implant Rehabilitation: A 10-Year Follow-Up

This report describes an atypical case of spontaneous mandibular regeneration of a large size bony defect after resection of an aseptic osteonecrotic area near the symphysis and parasymphyseal area. The patient underwent orthodontic therapy, vertical osteogenic distraction of the alveolar bone, and oral rehabilitation with an implant borne prosthesis. This case study also describes the 10-year follow-up of comprehensive multidisciplinary treatment and successful recovery of a patient's esthetic and functional aspects.

A patient with severe maxillary gingival exposure treated with combined compression osteogenesis of the anterior alveolar bone and conventional Le Fort I osteotomy

Excessive gingival exposure at the maxillary anterior region during not only smiling (a gummy face) but also at rest creates both functional and aesthetic problems for patients. We herein introduce a unique treatment procedure for mandibular retrognathia with a gummy face. This procedure combines conventional Le Fort I osteotomy and following corticotomy at the anterior region of the maxilla. Subsequently, the anterior segment is continuously compressed (compression osteogenesis) in a posterior-superior direction until it reaches an ideal position. This procedure appears to safely and adequately resolve both the aesthetic and functional complaints associated with patients with a gummy face.

Partially Biodegradable Distraction Implant to Replace Conventional Implants in Alveolar Bone of Insufficient Height: A Preliminary Study in Dogs

BACKGROUND

Dental implants have been widely used in the last few decades. However, patients with insufficient bone height need reconstructive surgeries before implant insertion. The distraction implant (DI) has been invented to simplify the treatment procedure, but the shortcomings of DIs have limited their clinical use. We incorporated biodegradable polyester into a novel DI called the partially biodegradable distraction implant (PBDI).

PURPOSE

The purpose of this study was to assess the radiological, histological, and biomechanical properties of the PBDI in animal models.

MATERIAL AND METHODS

PBDIs were manufactured and inserted into the atrophied mandibles of nine dogs. Box-shaped alveolar bones were segmented and distracted. The dogs were randomly divided into three groups that were sacrificed 1, 2, and 3 months after the implant insertion. Actual augmentation height (AAH) of the bone segments was measured to evaluate the effect of distraction. X-ray examination and micro-CT reconstruction and analysis were used to evaluate the regenerated bone in the distraction gap and bone around the functional element. Histological sections were used to evaluate the osseointegration and absorption of the PBDI. Fatigue tests were used to evaluate the biomechanical properties of the PBDI.

RESULTS

Little change was found in AAH among the three groups. X-ray examination and micro-CT reconstruction showed good growth of regenerated bone in the distraction gap. Alveolar bone volume around the functional element increased steadily. No obvious bone absorption occurred in the alveolar crest around PBDI. Three months after distraction, the functional element achieved osseointegration, and the support element began to be absorbed. All PBDIs survived the fatigue test.

CONCLUSIONS

The PBDI is a novel and reliable dental implant. It becomes a conventional implant after the absorption of the support element and the removal of the distraction screw. It is a promising replacement for conventional implants in patients with insufficient alveolar bone height.

Horizontal Bone Augmentation Using Autogenous Block Grafts and Particulate Xenograft in the Severe Atrophic Maxillary Anterior Ridges: A Cone-Beam Computerized Tomography Case Series

The aim of the present study was to use cone-beam computerized tomography (CBCT) to assess horizontal bone augmentation using block grafts, harvested from either the iliac crest (IC) or mandibular ramus (MR) combined with particulate xenograft and a collagen membrane for in the severe maxillary anterior ridge defects (cases Class III-IV according to Cadwood and Howell's classification). Fourteen healthy partially edentulous patients requiring extensive horizontal bone reconstruction in the anterior maxilla were selected for the study. Nineteen onlay block grafts (from IC or MR) were placed. The amount of horizontal bone gain was recorded by CBCT at 3 levels (5, 7, and 11 mm from the residual ridge) and at the time of bone grafting as well as the time of implant placement (≈5 months). Both block donor sites provided enough ridge width for proper implant placement. Nonetheless, IC had significantly greater ridge width gain than MR (Student t test) (4.93 mm vs 3.23 mm). This was further confirmed by nonparametric Mann-Whitney test (P = .007). Moreover, mean pristine ridge and grafted ridge values showed a direct association (Spearman coefficient of correlation = .336). A combination of block graft, obtained from the IC or MR, combined with particulate xenograft then covered with an absorbable collagen membrane is a predictable technique for augmenting anterior maxillary horizontal ridge deficiency.

Osteodistraction of mandibles with a small bone defect at the planned osteotomy site: a histological pilot study in dogs

AIM

To develop a treatment plan for cases in which a bone defect is located on the osteotomy line of mandibular osteodistraction (DO).

SUBJECTS AND METHODS

Bilateral DO was performed in 17 Mongrel dogs. Prior to surgery, the 34 hemi-mandibles were randomly allocated to three groups: C (n = 10; a standard DO was performed), D - G (n = 12; a bone defect was created on the DO osteotomy line), and D + G (n = 12; the bone defect on the osteotomy line was grafted). After one week of latency, 8 days of distraction, and 4 weeks of consolidation the animals were sacrificed, and the newly formed bone were examined.

RESULTS

In group C, two zones of immature trabecular bone originating from host bone margins were separated by a central fibrous zone. In group D + G uniform new bone formation of the entire distraction gap was observed. In group D - G the distraction gap was mainly filled with fibrous tissue. The values for the newly formed bone volume and trabecular thickness were not significantly different between groups D + G and C, but were higher than values in group D - G (p < 0.05).

CONCLUSION

When a mandibular defect is located at the site of distraction osteotomy, DO can be performed simultaneous with bone grafting of the defect.