Complication rates and associated factors in alveolar distraction osteogenesis: a comprehensive review

Vertical Alveolar Ridge Regeneration by Means of Periosteal Activation-A Proof-of-Principle Study

AIM

To assess the possibility of vertical alveolar ridge augmentation by means of activation of the periosteum.

MATERIALS AND METHODS

Six adult male Beagle dogs were used for the study. All premolars and first molars were extracted, and one vertical saucer-shaped bony defect was created on each side of the mandible. After 3 months of healing, full-thickness muco-periosteal flaps were elevated, and one distraction device was placed on each side of the mandible. The distraction plate was left submerged, and the activation mechanism connected to the distraction rod was exposed intra-orally. The protocol of periosteal activation (PP: periosteal 'pumping') was initiated after a latency of 7 days. The alternation of activation and relaxation at the rate of 0.35 mm/12 h during 5 days was followed by the sole activation of 0.35 mm/12 h for 5 days (PP group). Devices were left inactivated on the contralateral control side of the mandible (C group). All animals were euthanized after 8 weeks of consolidation. Samples were analysed histologically and by means of micro-CT.

RESULTS

New mature lamellar bone was formed over the pristine bone in all groups. More intensive signs of bone modelling and remodelling were observed in the PP group compared to the C group. Mean new bone, bone marrow, connective tissue and total volumetric densities were greater in the PP group (p < 0.001, p = 0.001, p = 0.003 and p < 0.001, respectively). No differences were observed in the relative area parameters. Total tissue volume and bone volume were higher in the PP group (p = 0.031 and p = 0.076, respectively), while the bone mineral densities were higher in the C group (p = 0.041 and p = 0.003, respectively). Trabecular number, trabecular thickness and trabecular separation values were similar between the two groups.

CONCLUSIONS

Regeneration of vertical alveolar bone ridge defects may be enhanced by activation of the periosteum, without the application of bone grafting materials.

Scalp-Split Technique: A Concept of Bone Splitting and Expansion for Thin Alveolar Ridges to Place Dental Implants

Bone expansion is when the existing bone at the implant site is split and separated to create a gap to widen it. This article introduces a novel concept of bone expansion for the ultrathin alveolar ridges to place dental implants with zero wastage of existing natural bone in long-term edentulous arches. Instead of using twist drills and piezo surgery kits, the bone is split with a surgical scalpel blade to prevent natural bone wastage. The split helps to expand the bone horizontally by using expanders to accommodate the smaller diameter implants. This technique was applied to 12 individuals to rehabilitate their atrophic edentulous mandibles to facilitate the implant-supported overdentures, and it revealed that all the cases achieved successful osseointegration after placing implants following this method. The scalp-spilt technique is promising for providing implant-retained or implant-supported prostheses over ultrathin edentulous alveolar ridges.

Long-term Follow-up of Implant Installation Following Multiple Distraction Osteogenesis in Maxillofacial Gunshot Wounds

Distraction osteogenesis (DO) is a reconstruction technique developed in the fields of oral and maxillofacial surgery and plastic surgery, addressing both vertical and horizontal bone deficiencies and enhancing soft tissue volume to facilitate subsequent dental implant placement. In this treatment method, devices are placed to stretch the bone gradually to stimulate the formation of new bone, effectively filling the existing defect to treat maxillofacial deformities or repair posttraumatic injuries. This case report presents an almost 20-year long-term follow-up of jaw defect reconstruction resulting from a gunshot injury, using DO with multiple distractors. Details on the frequency, period of DO, and subsequent implant installation in the distracted anterior jaw area are outlined. This case exhibits DO treatments that reconstructed effectively severe bone defects in the jaws. The quality of bone generated during the DO process was both functionally and esthetically satisfactory for subsequent implant rehabilitation.

Simultaneous or staged lateral ridge augmentation: A clinical guideline on the decision-making process

Lateral ridge augmentation is a standard surgical procedure that can be performed prior to (staged) or simultaneously with implant placement. The decision between a simultaneous or staged approach involves considering multiple variables. This paper proposed a decision-making process that serves as a guideline for choosing the best treatment choice based on the available evidence and the author's clinical experience.

Evaluation of osteogenic potential of Cissus quadrangularis on mandibular alveolar ridge distraction

BACKGROUND

This randomized clinical trial was designed to evaluate osteogenic potential of Cissus quadrangularis in alveolar distraction to facilitate implant installation.

MATERIAL AND METHODS

Twenty patients with atrophic ridge were treated by alveolar distraction. After completing distractor activation, patients were randomly divided into two equal groups according to administered drug (placebo and Cissus quadrangularis group). After a consolidation period, distractors were removed and implants were inserted. Clinical evaluation was done to assess wound healing, and distractor and implant stability. Histological evaluation was performed at time of implant insertion. Radiographic evaluation was performed to assess bone volume and density after distraction, as well as, density and bone loss around implant.

RESULTS

Radiographic and histological results showed that bone formation and maturation of study group were faster than that of control group. There was a significant increased bone density in distracted area and around implant in study group than control group. A significant bone loss at end of consolidation period, and around implant at end of the study was reported in control group than study group.

CONCLUSION

Cissus quadrangularis administration during the consolidation period is associated with increased osteogenic potential of distracted bone. The histological and radiographic findings of current study proved that Cissus quadrangularis not only enhances rate of new bone formation, but also bone density to withstand the biomechanical requirements of implant placement in a shorter time. Trial registration This study was retrospectively registered on www.ClinicalTrial.gov : NCT04669795-17\12\2020.

Evaluation of Resorption and Osseointegration of Autogenous Bone Ring Grafting in Vertical Bone Defect With Simultaneous Implant Placement in Dogs

The aim of this research was to evaluate the resorption and osseointegration of an autogenous bone ring, which was grafted in a local vertical alveolar defect with simultaneous implant placement. Six Beagle dogs were enrolled in the study; their 4 nonadjacent mandibular premolars were extracted, and the buccal plate was removed to create bone defects in 2 of the 4 sites. Three months after extraction, Straumann implants (Ø 3.3 mm, length of 8 mm) were placed in the bone defect sites with simultaneous autogenous bone ring grafting and in the conventional extraction sites. After a 3-month healing period and a 3-month loading period, the animals were euthanized. The harvested samples were analyzed using micro-computed tomography (CT) scanning and histological analysis. From the micro-CT measurements, the average vertical bone resorption of the bone ring was 0.23 ± 0.03 mm, which was not significantly different from that around the conventional implant, 0.24 ± 0.12 mm (P > .05). The ratio of the bone volume to the total volume of the bone ring group was 91.11 ± 0.02, which was higher than that of the control group, 88.38 ± 2.34 (P < .05). From the hard tissue section, the bone rings developed fine osseointegration with the implants and the base alveolar bone. The results suggest autogenous bone ring grafting with simultaneous implant placement can survive in a local vertical bone defect with little bone resorption and good osseointegration in dogs with strict management. A bone ring graft must be compared with guided bone regeneration, and a larger and longer observation must be confirmed in clinical patients.

Does the Animal Model Influence in Vertical Alveolar Distraction? A Systematic Review of the Literature

Simple Summary

Vertical alveolar osteogenesis distraction (VAOD) technique appears to provide the best results in terms of vertical bone gain. Before its use in humans, most devices are tested on experimental animals. Currently, there is no consensus on which is the ideal biological animal model for VAOD studies. In this review, it has been found that the animal model influences the results. In addition, the most used, easier to handle, and with less complications was the Mongrel dog. The use of pigs and minipigs, given their difficult handling and poor hygiene, is not recommended.

Abstract

This study is aimed at synthesizing all available evidence on vertical alveolar osteogenesis distraction (VAOD) in animal trials to determine whether the animal model used and its handling influence or not, and find which is the most appropriate animal model for this specific technique. This systematic review has been carried out following the PRISMA statements. Bibliographic sources have been consulted manually by two reviewers. Risk of bias was assessed using a version of the Newcastle-Ottawa-Scale (NOS). The selection criteria established by expert researchers were applied in order to decide which studies should be included in the review. Twenty-six studies met the inclusion criteria and were included in the review. Twenty-four of them had a high quality (score between 7 and 9), two medium quality (score between 4 and 6), and none low quality (score between 1 and 3). The highest possible score was 9 (using the NOS). Six studies complied with all NOS criteria. The animal model has been seen to influence the results, leading to failure in some cases. The most used animal model on VAOD, with fewer complications, was the Mongrel dog. The use of the pig and minipig is not recommended, due to the difficulties in handling and complications encountered.

Experiment of Mechanical Properties of a Customized Distractor Based on 3D Printing Technology

This study aimed to design and fabricate a customized distractor based on 3D printing technology and compare its mechanical properties with conventional distractor. The investigators designed and implemented a study composed of conventional and customized distractors. The design of customized distractor was based on the specification of conventional mandibular distractors and was fabricated using selective laser melting (SLM) technology. The same type of conventional distractors served as control group. Vickers-hardness test, three-point bending test and welding strength test were carried out for the conventional and customized distractor respectively and data was analyzed with t test using SPSS13.0 software package. The sample was composed of 18 distractors grouped as follows: customized distractor (n = 9) and conventional distractor (n = 9). The customized distractor showed better result than the conventional distractor in mechanical property tests, with statistically significant differences in Vickers-hardness and maximum load (P < 0.05), and no significant differences in yield strength and welding strength (P > 0.05). The results of this study suggest indicated that compared to the conventional distractor, the customized distractor had better mechanical properties and could be used in maxillofacial distraction osteogenesis.

Bone Augmentation Techniques for Horizontal and Vertical Alveolar Ridge Deficiency in Oral Implantology

Bone deficiency is the major obstacle in implant dentistry. Guided bone regeneration (GBR) with particulate bone and barrier membranes has been the primary surgical technique used to regenerate alveolar bone for dental implant therapy. This procedure has been used in implant dentistry for more than 30 years and continues to be developed and refined for more predictable surgical outcomes. This article reviews GBR and alternative ride expansion procedures and reviews the use of various particulate graft materials. Alveolar distraction osteogenesis, used as an augmentation technique, is also presented.

Does Guided Bone Regeneration Prevent Unfavorable Bone Shapes in Distraction Gap?

PURPOSE

Complications related to distraction osteogenesis can cause degradation of newly regenerated bone. Additionally, an unfavorable shape of the regenerated bone at the distraction gap can reduce the quantity of regenerated bone. The aim of the present study was to report on the prevention of unfavorable shapes of regenerated bone using guided bone regeneration during distraction.

MATERIALS AND METHODS

Bilateral alveolar distraction was performed in 10 beagle dog mandibles. One side of the mandible formed the experimental group and the other side served as the control group. In the experimental group, guided bone regeneration was performed simultaneously with distraction osteogenesis. In the control group, only alveolar distraction was applied. At the end of a 1-week latent period, all mandibles were distracted 10 mm (1 mm/day). After the distraction period, 3 months were allowed for consolidation. After consolidation, all the dogs were euthanized, and the shape of the regenerated bone was determined to be either favorable or unfavorable. Densitometric evaluation and area measurements were performed using computed tomography scans. Statistical evaluation was performed using the independent t test, with a significance level of P < .05.

RESULTS

In the experimental group, no unfavorable bone shape developed in the distraction gap, and the new bone had a surface and volume similar to those of the segments. In contrast, in the control group, 4 mandibles had an unfavorable bone shape in the distraction gap and 4 showed favorable bone healing with no defect. The surface area of the regenerating bone in the experimental group was significantly greater than that in the control group. Also, the surface area differed significantly between the experimental and control groups (P < .05). However, the densitometric values did not differ between the 2 groups (P < .05).

CONCLUSIONS

Concomitant use of guided bone regeneration with distraction osteogenesis could be an optimal method for generating a favorable bone shape within the distraction gap.

Alternative Distraction Osteogenesis Technique After Implant Placement for Alveolar Ridge Augmentation of the Maxilla

An alternative technique to reconstruct atrophic alveolar vertical bone after implant placement is presented. The technique consists of distraction osteogenesis or direct surgical repositioning of an implant-and-bone block segment after segmental osteotomies that can be used in esthetic or unesthetic cases. Initially, casts indicating the implant position are obtained and the future ideal prosthetic position is determined to guide the model surgery. After the model surgery, a new provisional prosthesis is fabricated, and an occlusal splint, which is used as a surgical guide and a device for distraction osteogenesis, is custom fabricated. Then, the surgery is performed. For mobilization of the implant-and-bone block segment, 2 vertical osteotomies are performed and then joined by a horizontal osteotomy. The implant-and-bone block segment is moved to the planned position. If a small movement is planned, then the implant-and-bone segment is stabilized; for larger movements, the implant-and-bone segment can be gradually moved to the final position by distraction osteogenesis. This technique has good predictability of the final position of the implant-and-bone segment and relatively fast esthetic rehabilitation. It can be considered for dental implants in regions of vertical bone atrophy.

Is it possible to change of the duration of consolidation period in the distraction osteogenesis with the repetition of extracorporeal shock waves?

BACKGROUND

In this study we examined the effects of two different repeated Extracorporeal Shock Waves (ESW) on the consolidation period of the distraction osteogenesis (DO) of the rabbit mandible using stereological, radiological and immunohistochemical methods.

MATERIAL AND METHODS

DO was performed unilaterally in the mandible of 18 New Zealand rabbits (six months old, weighing between 2.5-3 kg). In the consolidation period, rabbits were divided into three groups randomly after the distraction period. The distraction zone of the mandible was received no treatment as controls (E0*2). Group 2 (E 500*2) received ESWT (twice 500 impulses at 14 kV and 0.19 mJ/mm2 energy) in the first and fourth days of the consolidation. Group 3 (E1000*2) treated with ESWT (twice 1000 impulses at 14 kV and 0.19 mJ/mm2 energy) in the first and fourth days of the consolidation period. After the sacrification, radiologically bone mineral density, new bone formation, new fibrous tissue and new vessel formation were analyzed by stereological.

RESULTS

It was found a statistically significant difference between the study groups and control group in the bone mineral density measurements and the highest value was in the E1000*2 group. In the stereological analysis, new bone formation was highest in the E1000*2 group and there was a significant difference compared to the other groups (E0*2 and E500*2) (p=0.000). The lowest connective tissue volume was found in the E500*2 and there was a significant difference compared to the other groups (E0*2 and E1000*2) (p=0.000). The volume of the new vessel was highest in the E500*2 and lowest in the E0*2 group. It was found statistically significant difference between the values of the study and control groups.

CONCLUSIONS

Interestingly, we found that repetition of the 1000 impulses ESWT accelerated the consolidation, 500 impulses ESWT extended consolidation period of the DO.

Vertical Alveolar Distraction Osteogenesis of the Atrophic Posterior Mandible Before Dental Implant Insertion

PURPOSE

Augmentation of deficient mandibular posterior alveolar ridges poses a great challenge because of extensive bone deficiency and the presence of the inferior alveolar nerve. This study sets its focus on vertical alveolar distraction osteogenesis (ADO) at the posterior mandible before dental implant placement.

MATERIALS AND METHODS

The study included 21 sites in 18 patients with severe mandibular posterior alveolar ridge deficiency. A trapezoidal osteotomy was performed, and an extraosseous alveolar distraction device was fixed and activated after a 4-day latency period at a rate of 0.5 mm/day. After a 4-month retention period, the distraction device was removed and titanium dental implants were placed.

RESULTS

A mean vertical augmentation of 14.47 mm was gained. The newly formed bone was shown using panoramic radiography and computed tomography. We placed 56 dental implants, and during a minimum follow-up period of 36 months, 2 implants were lost, resulting in a success rate of 96.42%.

CONCLUSIONS

ADO offers marked vertical ridge augmentation with simultaneous soft tissue expansion and stable results. ADO diminishes the need for autogenous bone graft, thus sparing donor-site morbidity. ADO of the deficient posterior mandibular alveolar ridge is useful in moderate to severe bony deficiencies and allows for adequate bone formation, which allows implant insertion.

Vertical distraction osteogenesis combined with bilateral 2-step osteotomy for preprosthetic rehabilitation of edentulous mandible

The aim of the current study was to appraise the effectiveness of distraction osteogenesis combined with bilateral 2-step osteotomy for the vertical augmentation of atrophic edentulous mandibles. To verify the predictability of this technique, we evaluated bone density and vertical bone gain of a cohort of 27 patients. The intraoral alveolar distractor was placed in the symphyseal area; then, it was left in situ for 2 months after surgery to consolidate the newly formed bone. A total of 189 implants were inserted. The main complications' issue was tied up to the neurosensory disturbances of the inferior alveolar nerve, which disappeared few months after the surgery.At the end of the distraction osteogenesis, a mean vertical bone gain of 10.5 mm evaluated by comparing preoperative and postoperative computed tomography was reached. Three months after the surgery, the radiologic data indicated that the difference in the mean bone density, recorded in Hounsfield units (HU), between the distracted bone and the preexisting mandibular bone was not statistically significant (P > 0.05). The last measurements done showed that the osseous density in the distraction chamber was higher than the original medullary bone density: the regenerated bones were more dense (876.8 [205.9] HU) than the preexisting medullary bone (312.1 [142.3] HU) and less dense than the preexisting cortical bone (1721.1 [170.4] HU) at the ninth month.In conclusion, this approach appeared to be a viable solution for the improvement of vertical volume in atrophic mandibles.

Complications in the treatment with alveolar extraosseous distractors. Literature review

Background

To review the literature that analyses the types and frequency of complications associated with the use of extraosseous alveolar distraction from 2007 to 2013.

Material and Methods

Review of the literature in PubMed, using these keywords; alveolar ridge, alveolar distraction osteogenesis, complication, literature review. Inclusion criteria were: articles published between 2007 and 2013 that included the distraction protocol, the complications encountered and the time when they occurred.

Results

According to the above criteria, 12 articles were included in this review, where 334 extraosseous distractors were placed and 395 complications were encountered, of which 19 (4.81%) were intraoperative, 261 (66.07%) postoperative and 115 (29.11 %) were postdistraction. The most common complication was the incorrect distraction vector found in 105 cases (26.58%), in 23 cases (5.82%) there were severe complications, of which 14 (3.54%) were mandibular fracture and 9 (2.27%) were fractures of the distractor elements.

Conclusions

According to this review, although alveolar distraction is a safe and predictable technique, it can cause complications; however, they are usually minor and easily resolved without affecting the treatment outcome.

Key words: Alveolar ridge, alveolar distraction osteogenesis, complication, literature review.

Clinical study comparing alveolar distraction using the lead system and MODUS MDO 1.5/2.0

This article compares 2 different alveolar distractors: Lead System (LS) and MODUS MDO 1.5/2.0 (M-MDO). This is a clinical retrospective study; 32 distractions were performed. We used the LS distractor (intraosseous) on 24 patients and the M-MDO (extraosseous) on the other 8. The variables included bone alveolar ridge height, alterations of the oral mucosa, number of distractors, implant survival, and complications. We also developed descriptive and univariate statistical analysis. The mean increase of bone height after performing the alveolar distraction was 6.15 mm, 5.74 mm with LS, and 8.36 mm with M-MDO (P < 0.0001). The survival rates of the implants in the intraosseous and extraosseous groups reached 100%. However, the use of M-MDO resulted in a significant defect in the alveolar mucosa during implant insertion (100%), an event that did not occur when using LS (P < 0.001). The most common complication in the intraosseous group was the tilting of the segment (25%), whereas, in the extraosseous group, the main difficulty was the rod interference with the opposing arch (75%). Bone defects after alveolar distraction appeared both in the intraosseous group (66.7%) and in the extraosseous group (50%). Both the LS and the M-MDO distractors are effective for alveolar bone distraction. The choice of one distractor over another depends on the clinical characteristics of each case, such as the size and shape of the defect, the patient's tolerance, the distance to the opposing arch, and the surgeon's experience.

Modified ridge splitting and bone expansion osteotomy for placement of dental implant in esthetic zone

Ridge splitting with bone expansion is a technique of manipulation of bone to form receptor site for implant without removing any bone from the implant site. Maxillary bone has inherent quality of flexibility which can bemolded to desire location by using series of instrument namely chisels and osteotome. This further improves quality of bone all around implant, at the crest and apex both. This article describes a report of a clinical case with management of bucco-palatal ridge defect with modified ridge splitting and expansion osteotomy technique using chisel and osteotomes in an esthetic zone.

An alternative solution for a complex prosthodontic problem: a modified Andrews fixed dental prosthesis

This report describes the prosthodontic rehabilitation of an alveolar defect in the posterior mandible after the excision of an odontogenic myxoma. A minimally invasive technique that involves a modification of the traditional Andrews fixed dental prosthesis was used to replace both soft and hard tissues. The clinical stages and materials used to provide this treatment are discussed.

The animal experiment of a new optimised distraction implant

Our aim was to evaluate the function of a new optimised distraction implant. Six dogs with alveolar bone defects had a total of 18 distraction, and 6 normal, implants inserted into edentulous mandibular ridges after osteotomy. Five days after insertion the distraction implants were activated at a rate of 1 mm/2 days to achieve a distraction height of 6mm. Radiographs were taken at 0, 1, 2, and 3 months after distraction. Two dogs were killed after 1, 2, and 3 months, respectively, and 12 distraction implants taken from the different time points were evaluated by microcomputed tomographic (MicroCT) scanning and histological examination. The other 6 distraction, and the 6 normal, implants were compared after osseointegration with a fatigue test. The results showed that all the distraction implants had successfully distracted the bone to the anticipated height. Radiographs showed that the density of the regenerated bone increased steadily during the consolidation period. MicroCT showed that the regenerated bone was comparable with the native bone 3 months after distraction. Both native and regenerated bone had osseointegrated histologically by 1 month and 3 months after distraction. The experiment successfully confirmed the usefulness and feasibility of this new distraction implant, and suggests interesting clinical uses.

Lateral transport osteogenesis in maxillofacial oncology patients for rehabilitation with dental implants: a retrospective case series

Objectives: To report on the use of lateral transport osteogenesis in cancer patients after maxillo/mandibular resections and on the implant survival rate in the generated bone Material and Methods: Four patients treated using lateral transport osteogenesis entered this descriptive study and were retrospectively studied (mean age 55; range 41-62). Results: Reconstruction of segmentary defects after surgical and radiological cancer treatment on maxilla and mandible was achieved. No relevant intra- or post-operative complications occurred. No differences on implant survival were observed between patients who had received radiotherapy and those who had not. Conclusions: This approach can be considered a recommendable reconstructive option after oral cancer treatment –including radiotherapy- particularly for high-surgical-risk, collaborative patients.

Key words:Distraction osteogenesis, oral cancer, radiotherapy, reconstruction, dental implants.

Prevention of lingual inclination of the transport segment in vertical distraction osteogenesis in the mandible

Vertical distraction osteogenesis can extend not only to hard tissues but also to soft tissues. There is a tendency to cause progressive lingual inclination of the distracted segment. This study describes a method for preventing the lingual inclination of the transport segment in patients with vertical distraction osteogenesis in the anterior region of the mandible and reports the results of long-term follow-up. The subjects included 5 patients who had severely atrophic ridges in the anterior mandible. In all cases, a part of the mental protuberance was scraped out, and the distractor was placed suitably in a labioinclination beforehand. Therefore, the transport segments did not lean to the lingual side and had long-term stability.

Biomechanical optimisation of the length ratio of the two endosseous portions in distraction implants: a three-dimensional finite element analysis

Insufficient alveolar height is one of the most common problems in oral implantation, and it may preclude placement of an implant or compromise the final aesthetic outcome of the restoration. To solve this problem, distraction implants (DIs) have been introduced because they can fulfill the functions of bony augmentation and implantation simultaneously and facilitate the operation, minimise the trauma, and shorten the duration of treatment. However, the high risk of complications such as device fracture from uneven distribution of stress or transport bone resorption from insufficient blood supply, has impeded their clinical use. As the cortical transport portion of the DI is more important for bearing occlusal force than the apical support portion, and the length of the transport portion is normally the height of the transport bone segment, lengthening the transport portion may help to obtain a rational distribution of stress and increase the blood supply to the transport bone. For those cases in which alveolar height is limited, the dimension of the DI must be minimised to be applicable, so it is important to find an optimised balance between the lengths of the transport and support portions for a better performance. We have made a finite element analysis to optimise the length ratio of transport:support portions. The effects of the length ratios on the stress distribution in the jawbones were evaluated. A ratio of 8:2 showed the minimum stress and most resistance to displacement. These results provide a valuable reference for further improvement of designs of DI and help to promote its clinical application.

Relative contributions of osteogenic tissues to new bone formation in periosteal distraction osteogenesis: histological and histomorphometrical evaluation in a rat calvaria

BACKGROUND

The relative contributions of different, potential factors to new bone formation in periosteal distraction osteogenesis are unknown.

PURPOSE

The aim of the present study was to assess the influence of original bone and periosteum on bone formation during periosteal distraction osteogenesis in a rat calvarial model by means of histology and histomorphometry.

METHODS

A total of 48 rats were used for the experiment. The contribution of the periosteum was assessed by either intact or incised periosteum or an occlusive versus a perforated distraction plate. The cortical bone was either left intact or perforated. Animals were divided in eight experimental groups considering the three possible treatment modalities. All animals were subjected to a 7-day latency period, a 10-day distraction period and a 7-day consolidation period. The newly formed bone was analyzed histologically and histomorphometrically.

RESULTS

New, mainly woven bone was found in all groups. Differences in the maximum height of new bone were observed and depended on location. Under the distraction plate, statistically significant differences in maximum bone height were found between the group with perforations in both cortical bone and distraction plate and the group without such perforations.

CONCLUSIONS

If the marrow cavities were not opened, the contribution to new bone formation was dominant from the periosteum. If the bone perforations opened the marrow cavities, a significant contribution to new bone formation originated from the native bone.

3D vector control during alveolar ridge augmentation using distraction osteogenesis and temporary anchorage devices: a new technique

This report describes a combined orthodontic surgical technique involving vertical alveolar distraction using temporary anchorage devices (TADs) in cases of massive alveolar ridge bone and teeth loss. A combined surgical orthodontic protocol included presurgical orthodontic preparation and a preimplantation surgical augmentation stage for insertion of a vertical distractor. During the active vertical alveolar distraction process TADs were inserted. Intraoral orthodontic elastics were attached to the main orthodontic archwire exerting multidirectional forces to control the vertical distraction vector. After 3 months of vector controlling and active bone moulding, the TADs were removed. Anterior alveolar ridge augmentation using distraction osteogenesis was achieved. The application of TADs for better anterior segment curvature enabled dental implant insertion, better positioning and restoration. A combined surgical orthodontic management protocol involving vertical alveolar distraction osteogenesis for augmentation purposes is an efficient treatment method to improve alveolar ridge volume for the preimplantation stage.

Soft tissue changes during distraction osteogenesis

This study aimed to investigate soft tissue changes in distraction osteogenesis depending on various distraction and consolidation periods. Fifteen male rabbits were divided into three groups and evaluated for five parameters. An external custom-made device was placed on the right side of the mandible. The postoperative latent period was 4 days. The groups were distracted for different periods (6 days, 3mm; 11 days, 5.5mm, 16 days, 8mm). For histomorphometric analyses, specimens were retrieved from both study and control sides of the mandible and were examined with light microscopy. The number of muscle fibres and nuclei on the study side increase proportionally with the distraction period. Regeneration in the first group continued in its natural pattern; in the second group, there seemed to be degeneration rather than regeneration; and in the third group there seemed to be a balance between regeneration and degeneration processes. In conclusion, when a massive amount of bone is to be obtained, instead of distracting the bone at once, it is thought to give better results if the total amount of distraction is divided into several time periods.

Single-stage implantation in the atrophic alveolar ridge of the mandible with the Norian skeletal repair system

Dental implants have played a part in rehabilitation of the jaws for more than 40 years, but in some cases they alone are inadequate because of extreme alveolar resorption. Correction may necessitate a two-stage procedure with additional interventions. We have made a preliminary study of the use of the Norian skeletal repair system (SRS), a carbonated calcium phosphate bone cement used to augment the alveolar ridge as a single-stage procedure, with the placement of implants. Ten edentulous patients with insufficient vertical bone in the interforaminal area were treated. After a horizontal osteotomy and crestal mobilisation of the alveolar ridge, implants were placed through the crestal part and fixed in the basal part of the mandible. Norian SRS was used to fill the gap created. The prostheses were inserted 3 months later. Forty implants were inserted. The follow up period was 60 months, and no fractures or dislocations developed. One of the implants was lost and there was one wound dehiscence, but no surgical intervention or revision was necessary. Radiographs showed good consolidation of the bony structure in all cases. We have described a reliable, single-stage procedure for augmentation and implantation in a highly atrophic alveolar crest. A 98% survival is comparable with those of other techniques. Further clinical trials are necessary to replicate these promising results.

Prosthetic rehabilitation of edentulous ridges following alveolar distraction osteogenesis: clinical report of three cases

Patients with complete edentulism who have insufficient bone for endosseous dental implant treatment present a challenge for dental practitioners. Distraction osteogenesis of the edentulous alveolar ridges is a process for augmentation of atrophic alveolar bone before dental implant placement. This clinical report describes the use of distraction osteogenesis and rehabilitation of patients with a fixed or removable implant-supported prosthesis to treat mandibular defects. Two female patients with segmental alveolar atrophy at the posterior regions of mandible and one female patient with defect at the anterior region of mandible were treated using distraction devices. However, lingual tipping of the distraction vector occurred during the distraction phase in patient 1. The morphology of the alveolar bone was also analyzed in relation to the planned implant position. After a consolidation period of 12 weeks on average, radiologic observation suggested that there was sufficient bone formation for implant installation. In all patients, implant-supported fixed or removable prosthetic oral rehabilitation was successfully performed, and the clinical and radiologic findings were satisfactory. After 4 years of follow-up, no functional or esthetic difficulties with the implants and restorations were noted. These case reports suggest that although alveolar distraction osteogenesis seems to be an effective technique for augmenting atrophic alveolar bone for creating bone and soft tissue, complications may occur after surgical procedures.

Miniscrew-anchored alveolar distraction for the treatment of the ankylosed maxillary central incisor

This report presents the case of a 20-year-old female patient exhibiting an infraoccluded ankylosed maxillary central incisor that was avulsed and replanted after traumatic injury during childhood. To reposition the osseous and gingival margins of the ankylosed tooth to an ideal level, a new alveolar distraction device that uses anchoring miniscrews with a single tooth dento-osseous osteotomy was fabricated and the ankylosed tooth was successfully treated with exceptional patient compliance.

Curvilinear mandibular distraction results and long-term stability effects in a group of 40 patients

BACKGROUND

The mandibular internal curvilinear distractor design produces a curvilinear vector to provide ideal three-dimensional curvilinear movements compared with the limited straight unidirectional predecessor devices. In this manner, it corrects craniofacial deformities as anatomically as possible, allowing simultaneous bidirectional (rotational and translational) mandibular movement and multidirectional distraction. The aim of this study was to quantify the sagittal and vertical mandibular changes achieved through curvilinear distraction and to assess the long-term effect of this generated bone.

METHODS

Forty patients (20 male and 20 female), with ages ranging from 5 to 55 years, who underwent mandibular distraction from December of 1999 to August of 2007 at Lucile Packard Children's Hospital in Stanford, California, were included. Preoperatively, postoperatively, and at follow-up (at least 2 years following distraction), panoramic and lateral cephalometric radiographs were traced by plotting different skeletal landmark points and were then analyzed.

RESULTS

All patients tolerated the curvilinear distraction process well through completion. The average of the mandibular body elongation recorded was 8 to 9 mm and 6 to 8 mm in the panoramic and cephalometric radiographs, respectively; whereas the vertical change of the mandibular ramus achieved was 10 to 12 mm and 10 to 11 mm, respectively. The curvilinear distraction effect on the mandible was found to be significantly stable when the long-term follow-up measurements were compared with the postoperative data revealed in the panoramic and lateral cephalometric radiographs for the two dimensions.

CONCLUSION

The internal curvilinear device is an effective tool that achieves a stable mandibular distraction, resulting in the correction of craniofacial deformities.

Bone morphogenetic proteins in critical-size bone defects: what are the options?

The recent development of new orthopaedic devices and advanced techniques for soft-tissue reconstruction have clearly improved the outcome in trauma and orthopaedic surgery. Nevertheless, large bone defects are still difficult to treat and require a careful analysis of the situation. Individual planning of the reconstructive strategy is desirable. Bone morphogenetic proteins (BMPs) have successfully been applied in the clinical setting for the treatment of spinal fusion, fracture healing and delayed and non-unions. Following the 'diamond concept', surgeons have begun using BMPs for treatment of critical-size defects also--in most cases, 'off label'; different treatment strategies are currently being evaluated. BMPs are often used in combination with autogenic, allogenic, xenogenic or synthetic grafting materials and even with mesenchymal stem cells. In addition, gene therapy approaches present an attractive option. Experimental studies and first clinical results are promising in the use of BMPs for treatment of critical-size defects; however, there is obvious need for further controlled studies to define strategies.