Alveolar Distraction Osteogenesis for Dental Implant Preparation: An Update

Evaluation of the Effectiveness of Bone Grafting in Alveolar Ridge Augmentation Using the Two-Stage Splitting Technique

Stimulation of neoosteogenesis is the main mechanism of osseointegration during installation of dental implants, bone tissue recession, and alveolar process augmentation in adentia. In experiments on miniature pigs, we used the technology of two-stage splitting of the ridge of the alveolar process of the mandible in combination with a xenograft that was placed between the fragments of the split bone plate. The morphology of the reparative process and the distribution of osteogenic differentiation markers in the compact and trabecular bone of the alveolar crest were studied. Signs of reparative osteogenesis were observed in the bone regenerate that had a lamellar structure, formed osteons, and foci of woven tissue. It was found that the xenograft was replaced by newly formed trabecular bone tissue. These sites were characterized by increased expression of osteocalcin and CD44. Augmentation technology through two-stage splitting provides trophic relationship of osteoprogenitor cells and is an effective method of osteogenesis stimulation in the alveolar process.

Vertical Ridge Augmentation Using Distraction Osteogenesis Versus Autogenous Bone Grafting: A Systematic Review and Meta-Analysis

Aim

The aim of this systematic review was to systematically assess the papers comparing the surgical techniques of Alveolar Distraction Osteogenesis(ADO) and Autogenous Bone grafting (ABG) for Vertical Ridge Augmentation in terms of bone gain, bone resorption and incidences of complications.

Metholodology

The review was registered on PROSPERO with the ID : CRD42021237671. A broad electronic survey was conducted in the PubMed, Scopus, Web of Science, Cochrane Library, and Virtual Health Library databases of all studies published till 08/03/2022. Four studies fulfilled the criteria to carry out a meta-analysis a in which a total of 58 patients underwent ADO and 43 patients for ABG. A total of 133 implants were placed in the ABG group and 124 in the ADO group.

Statistical Analysis

DerSimonian-Laird estimator of variance was used for Random effect meta-analysis. The estimates of an intervention were expressed as the odds ratio (OR) and standard mean difference (SMD) in millimeters.

Results

There was statistically significant difference in terms of bone height gain with SMD of - 0.78 (95% 0.04-1.55) in ABG. Bone resorption and complications were statistically insignificant with SMD of 0.52 (95% - 1.59 to 0.56) and OR 0.55 (95% 0.18-1.70), respectively.PROSPERO Registration ID: CRD42021237671.

The orthodontic implant site-switching technique: a preliminary study in dogs

BACKGROUND

To evaluate the quantity and quality of bone in the newly formed edentulous area produced by the orthodontic implant site-switching technique.

METHODS

The bilateral maxillary first premolars of five beagle dogs were extracted and bone defects were created. The right and left sides of the maxilla were randomly divided into control and experimental sides. On the experimental side, the maxillary second premolar was mesially moved into the position of the missing first premolar. On the control side, the second maxillary premolar was extracted. Six months later, the beagles were euthanized. Microcomputer tomography was used to analyze bone microstructure parameters, alveolar bone height and alveolar bone width of the regenerated bone. Histological analysis was performed by staining tissue sections with toluidine blue.

RESULTS

Median BV/TV values in the experimental group (81.78%) were significantly larger than those in the control group (35.67%; p = 0.04). Median Tb.Sp values in the experimental group (0.14 mm) were significantly lower than those in the control group (0.54 mm; p = 0.04). Median Tb.Th values in the experimental group (0.48 mm) were significantly higher than those in the control group (0.21 mm; p = 0.04). Median Tb.Pf values in the experimental group (0.65/mm) were significantly lower than those in the control group (3.15/mm; p = 0.04). There was no significant difference in the trabecular number (Tb.N) between the two groups (p = 0.23). The median alveolar bone height values in the experimental group (-0.81 mm) were significantly higher than those in the control group (-2.11 mm; p = 0.04) at a distance 5 mm from the mesial CEJ of the third premolar. The median alveolar bone height values in the experimental group (0.45 mm) were significantly higher than those in the control group (-1.70 mm; p = 0.04) at a distance 6 mm from the mesial CEJ of the third premolar. There was no significant difference in alveolar bone width when compared between the two groups (p > 0.05).

CONCLUSIONS

The newly formed edentulous area created by orthodontic treatment had more compact and thicker trabeculae than the extraction socket. Furthermore, the newly formed edentulous area had a greater alveolar bone height available for the placement of implants.

Maxillary vertical alveolar ridge augmentation using computer-guided sandwich osteotomy technique with simultaneous implant placement versus conventional technique: A pilot study

BACKGROUND

Sandwich osteotomy technique (Inlay bone grafting) is considered as a highly reliable procedure for vertical bone augmentation in the maxillary anterior esthetic zone. The aim of this study was to compare vertical bone gain and palatal tipping using computer-guided inlay technique versus the conventional technique.

MATERIAL AND METHODS

This was a randomized clinical trial including 12 patients who were randomly divided into two groups: sandwich osteotomy with simultaneous implant placement at the anterior maxillary esthetic zone (six patients) using patient-specific guides (PSGs) in the study group versus conventional technique (six patients). In the control group, free-hand sandwich osteotomy was done, while in the study group all the procedures were performed with two sequential PSGs with cutting slits, guiding holes, and implant sleeves. Radiographic assessment included measurements of linear changes in the vertical dimensions of the labial plate of bone and palatal tipping on cross-sectional cuts of cone-beam computed tomography using special software.

RESULTS

All the procedures were uneventful except one case of the study group showed a cracked bony segment that did not affect the final outcome. Radiographic results showed comparable bone gain in both groups with no statistical significance difference (study group 4.4 mm, control group 3.9 mm). To the contrary, the computer-guided approach significantly reduced the palatal tipping to 0.4 mm compared to 2.1 mm in the conventional group, and there was a statistically significant difference between the two groups (p-value <0.001).

CONCLUSION

Sandwich osteotomy using PSGs appears to be efficient and showed promising results regarding improving the palatal tipping compared to the free-hand technique.

Maxillary horizontal alveolar ridge augmentation using computer guided ridge splitting with simultaneous implant placement versus conventional technique: A randomized clinical trial

BACKGROUND

Ridge splitting technique is considered one of the successful horizontal bone augmentation procedures especially for the maxillary bone, the aim of this study was to compare marginal bone loss using a novel ridge splitting protocol versus the conventional technique.

MATERIAL & METHODS

This was a randomized clinical trial including 20 patients who were randomly assigned to ridge splitting with simultaneous implant placement at the anterior maxillary aesthetic zone (10 patients, 29 dental implant) using patient specific guides (PSGs) or conventional technique (10 patients, 29 dental implant). In the control group free hand ridge splitting was done, while in the study group all the splitting and drilling procedures were done through specific slits and sleeves at the patient specific guides. Radiographic Assessment included measurements of linear changes in the vertical dimensions of the labial plate of bone on cross sectional cuts of computed tomography (CBCT) using mimics software.

RESULTS

Wound healing was uneventful for all the patients except one patient in the control group that showed bad split and another showed buccal fenestration. The study group showed lower bone loss (1.38 ± 0.61 mm) compared to the control group (2.42 ± 0.63 mm), with statistical significance difference (P value = 0.001). The loss percentage also was higher in the study group (10.99 ± 4.76%) compared to the control group (19.12 ± 4.53%), and there was statistical significance difference between the two groups (P value = 0.001).

CONCLUSION

Ridge splitting using PSGs appear to be efficient and promising than the free hand technique.

Vertical and Horizontal Augmentation of Deficient Maxilla and Mandible for Implant Placement

Ridge augmentation for implant procedures has been shown to be highly successful. There are several techniques available to the dentist, but they require some degree of surgical expertise and experience. No particular technique has been shown to be superior. This article presents the indications, techniques, and complications of the various procedures for alveolar ridge augmentation. This information will educate the general dental practitioner of the techniques available and provide information on the surgical procedures that could be used to discuss with patients when they are being referred to a specialist.

Implant Therapy in Alveolar Cleft Sites

Dental implant therapy in the non-cleft patient is familiar to most oral and maxillofacial surgeons. Understanding the differences in surgical treatment planning in the cleft patient versus the non-cleft patient is the key to highly functional and esthetic long-term outcomes. CBCT and computer-assisted planning, as well as improved technology in grafting and implant materials, result in excellent outcomes. Communication with the restorative team remains of paramount importance in planning treatment.

Cephalometric studies of the mandible, its masticatory muscles and vasculature of growing Göttingen Minipigs-A comparative anatomical study to refine experimental mandibular surgery

Over many decades, the Göttingen Minipig has been used as a large animal model in experimental surgical research of the mandible. Recently several authors have raised concerns over the use of the Göttingen Minipig in this research area, observing problems with post-operative wound healing and loosening implants. To reduce these complications during and after surgery and to improve animal welfare in mandibular surgery research, the present study elucidated how comparable the mandible of minipigs is to that of humans and whether these complications could be caused by specific anatomical characteristics of the minipigs' mandible, its masticatory muscles and associated vasculature. Twenty-two mandibular cephalometric parameters were measured on CT scans of Göttingen Minipigs aged between 12 and 21 months. Ultimately, we compared this data with human data reported in the scientific literature. In addition, image segmentation was used to determine the masticatory muscle morphology and the configuration of the mandibular blood vessels. Compared to data of humans, significant differences in the mandibular anatomy of minipigs were found. Of the 22 parameters measured only four were found to be highly comparable, whilst the others were not. The 3D examinations of the minipigs vasculature showed a very prominent deep facial vein directly medial to the mandibular ramus and potentially interfering with the sectional plane of mandibular distraction osteogenesis. Damage to this vessel could result in inaccessible bleeding. The findings of this study suggest that Göttingen Minipigs are not ideal animal models for experimental mandibular surgery research. Nevertheless if these minipigs are used the authors recommend that radiographic techniques, such as computed tomography, be used in the specific planning procedures for the mandibular surgical experiments. In addition, it is advisable to choose suitable age groups and customize implants based on the mandibular dimensions reported in this study.

Horizontal alveolar transport distraction osteogenesis followed by implant placement

Alveolar transport distraction osteogenesis (ATDO) is an alternative treatment method to vertical alveolar distraction osteogenesis in cases of large bony defects, especially when the bone is limited in size. ATDO was performed in 10 patients with 12 defects. The mean age of the patients was 39.1years. The average bone length gain was 18.2mm. Implants were inserted following a 3-month consolidation period. Three patients needed additional bone grafting for horizontal widening. Final prosthetic rehabilitation was performed at least 3 months following implant insertion. The mean follow-up period was 63 months and the survival rate of the 25 implants placed was 92%. All failures (n=2) occurred during the early healing period. Although the results are not totally predictable, it can be concluded that ATDO can be effective in the reconstruction of the alveolar crest prior to implant placement.

Strategies for alveolar ridge reconstruction and preservation for implant therapy

PURPOSE

In dental implant treatment, ridge preservation and immediate or early implant placement are recommended to minimize bone resorption after tooth extraction and achieve esthetic outcomes. However, there is no consensus concerning the efficacy of this surgical method. There is also no consensus on the efficacy of bone and soft tissue grafts and surgical methods for alveolar ridge reconstruction.

STUDY SELECTION

This paper reports ridge alteration in the anterior maxilla after tooth extraction, and summarizes the efficacy of various ridge preservation methods and immediate or early implant placement as alveolar ridge preservation methods to minimize bone resorption after tooth extraction. The advantages and complications of alveolar ridge reconstruction methods, and the efficacy and surgical method of soft tissue graft are reviewed.

RESULTS

The anterior maxilla is in the esthetic zone, and the thickness of the bone on the labial side around the natural tooth is less than 1mm in many cases. Therefore, it is impossible to prevent bone resorption completely, even if ridge preservation and immediate or early implant placement are performed after tooth extraction. It is necessary to obtain stable and long-term esthetics by combining connective tissue and free gingival grafts, in addition to hard tissue augmentation.

CONCLUSIONS

It is important to consider the burden and level of satisfaction of patients, such as in terms of donor site morbidity in hard and soft tissue grafting, and to pay attention to appropriate indications to avoid overtreatment.

A simple solution for vector control in vertical alveolar distraction osteogenesis

One of the important and frequent complications in alveolar distraction osteogenesis is vectorial change of the transport segment. This report presents a simple solution for vector angulation control by placing intermaxillary fixation screws intraoperatively. Advantages of the technique are also discussed.

Tilted implants for the restoration of posterior mandibles with horizontal atrophy: an alternative treatment

PURPOSE

Horizontal atrophy in the posterior mandible presents serious limitations on conventional implant placement. The purpose of this study was to evaluate the use of tilted implants angled in a buccolingual direction for restoring atrophic posterior mandibular sectors.

MATERIALS AND METHODS

A cohort study was performed of 25 patients who had partial prostheses supported by more than 1 implant (≥ 1 tilted and 1 axial implant) to restore molar areas in the mandible. When the bone thickness was at least 5 mm, axial implants were placed; when the alveolar ridge was narrower, the implant was placed with tilted angulation. The beds for these tilted implants were prepared using a lingual approach, tipping the implant apex toward the vestibule. Twelve months after loading, bone loss was evaluated and the success rates of the tilted and axial implants were calculated.

RESULTS

The study included 20 women and 5 men (mean age, 54.8 yr) who received 67 implants in the posterior mandibular sectors. Thirty-nine implants were placed with a buccal angulation and 28 implants were placed vertically. Mean bone losses of 0.59 ± 0.26 mm among the tilted implants and 0.48 ± 0.34 mm among the axial implants were observed 1 year after loading. The success rate of the tilted implants was 94.9%, and that of the axial implants was 100%. No significant differences in success rates or in bone loss between the tilted and axial implants were found at 12 months after loading.

CONCLUSIONS

Twelve months after loading, tilted implants provided good results for the restoration of posterior mandibles with horizontal atrophy and no significant differences in success rates or marginal bone loss between tilted and axial implants were observed.

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.

An oligodeoxynucleotide with promising modulation activity for the proliferation and activation of osteoblast

The paper explored the regulatory role of oligodeoxynucleotides (ODNs) with specific sequences in the proliferation and activation of osteoblast, using human osteoblast-like cell line MG 63 as the model. Through the administration of ODNs to MG 63 cells at a concentration of 1.0 μg/mL, ODN MT01 with positive effects on proliferation and activation of osteoblast was selected from 11 different ODNs by methyl thiazolyl tetrazolium (MTT) assay and alkaline phosphatase (ALP) activity measurement. To get a deeper insight into the molecular mechanism, effects of ODN MT01 treatment on the expression level of Sp7, runx-2, collagen-I, osteoprotegerin (OPG) and RANK ligand (RANKL) were determined using quantitative real time PCR and Western blotting. Remarkably, the mRNA and protein expression levels of Sp7, runx-2, collagen-I and OPG were improved after ODN MT01 treatment. Meanwhile, the protein expression level of RANKL was dramatically decreased. These results suggested that ODN MT01 had a significant impact in facilitating osteogenic proliferation and activation, and provided a direct evidence for the notion that single strand ODN could regulate the balance of bone formation and resorption, and thus was of great potential in the rebuilding of alveolar bone.