Reduction Of Alveolar Ridge Research Articles

Clinical and radiographic outcomes of a novel technique for socket healing: a protocol for a split-mouth randomized controlled trial

Abstract Tooth extraction is one of the most common routine procedures in the dental clinic. Tooth extraction is followed by an inevitable bone resorption that leads to alveolar ridge reduction in the horizontal and vertical directions. The dimensions of alveolar ridge after socket healing are the result of a balance between the resorption and remodeling mechanisms that occur naturally after tooth extraction. The aim of this study is to evaluate the clinical and radiographic outcomes of the socket decortication technique for socket healing through a split-mouth randomized controlled trial. The proposed research protocol will investigate the effectiveness of this technique in promoting optimal healing and reducing bone loss following tooth extraction. By comparing radiographic data from the intervention side with the control side within the same individual, the study seeks to provide valuable insights into the potential benefits of the novel approach. The findings of this study have the potential to advance current knowledge in the field of dentistry and contribute to improved clinical practices for socket healing.

Biomaterials for Alveolar Ridge Preservation as a Preoperative Procedure for Implant Treatment: History and Current Evidence.

In implant treatment, the reduction and structural changes in the alveolar ridge that occur after tooth extraction limit the length, width, and placement position of the implant body, impair esthetics, and, in some cases, make implant placement difficult. To solve these problems, an alveolar ridge preservation (ARP) technique, which is performed simultaneously with tooth extraction, generally aims to promote bone regeneration and prevent alveolar ridge reduction by filling the extraction socket with bone graft material and then covering it with a barrier membrane to protect against the invasion of epithelial tissue. The extraction socket provides a favorable environment for bone regeneration throughout the healing period because the blood supply is abundant, and it effectively retains the bone graft material by using the remaining bone wall of the socket. In recent years, advances in bioengineering technology have led to the development of graft materials with various biological properties, but there is currently no clear consensus regarding the selection of surgical techniques and materials depending on the condition of the alveolar ridge. This review will provide a comprehensive survey of the evidence accumulated to date on ARP, present many cases according to the clinical situation, and discuss various treatment options.

Digital workflow of labial guides for alveolar ridge reduction during implant-supported full-arch rehabilitation.

This article presents a technique for fabricating two-piece labial guides using resin and cobalt-chromium for guided alveoloplasty, implant placement, and immediate full-arch implant-supported fixed complete denture placement. This technique reduces tissue damage and overcomes the negative effect of the anatomical position of the palatal neuropore and mobility of the tissue flap on the positioning and stability of the guide. The use of labial retention metal guides with improved mechanical properties of cobalt-chromium and fixation plugs allows the unilateral placement of the guide. Thus, minimally invasive implant surgery can be performed owing to the absence of large palatal flap elevation and obstruction. Such a design provides better stability of the guides and clear visual access during surgery.

Use of transcortical miniscrews for alveolar ridge preservation following tooth extraction: A pilot study.

The purpose of this split-mouth pilot study was to investigate the effects of a transcortical miniscrew placed over the buccal plate of an extraction socket for alveolar ridge preservation in humans. One week after the extraction of bilateral maxillary premolars, cone-beam computed tomography (CBCT) and intraoral digital imaging were performed (T0). A transcortical miniscrew was placed over the buccal plate of the extraction socket on one side (experiment), and the extraction socket on the contralateral side was left untreated (control). Follow-up CBCT and intraoral digital imaging were performed at 8months immediately after miniscrew removal (T8). Changes in the width of the alveolar bone and ridge were measure by superimposing T0 and T8 of CBCTs and intraoral digital scans. Six participants completed the study protocol. Overall, the experimental side with the miniscrew demonstrated less bone loss and less alveolar ridge reduction than the control side. Bone loss on the experimental side (0.7±0.2mm) was significantly less than that on the control side (1.3±0.7mm) at the apical level of the socket on axial CBCT imaging (Wilcoxon signed rank test, p=.031). The experimental side (-18±8%) exhibited less reduction in the alveolar ridge width than the control side (-21±12%) at the crestal level on coronal superimposition of the intraoral digital scans. Transcortical miniscrew placement over the buccal plate of the extraction socket resulted in less resorption of the alveolar ridge and bone 8months after tooth extraction. NCT03205800: Temporary Anchorage Devices for Ridge Preservation (TAD).

Enamel matrix derivative promotes new bone formation in xenograft assisted maxillary anterior ridge preservation-A randomized controlled clinical trial.

To compare the effectiveness of deproteinized bovine bone mineral with 10% collagen alone (DBBMC) or with enamel matrix derivative (DBBMC-EMD) in ridge preservation. 42 maxillary anterior teeth were extracted and received either a DBBMC (control) or DBBMC-EMD (test) treatment protocol. CBCT taken before and 4months after the extraction procedure was used to measure changes in alveolar ridge width (RW), buccal bone height (BH) and palatal bone height (PH). Bone cores were harvested during implant osteotomy preparation, and the samples processed histomorphometrically to assess the fraction of new bone (%NB), residual graft (%RG) and soft tissue matrix (%STM). Overall, both treatment groups showed significant reductions in mean RW from baseline to 4months after extraction, but no significant change in either mean BH or PH over this time. When CBCT measurements were analysed according to the initial thickness of the buccal wall (BT<1mm vs. BT≥1mm), significant reductions in all ridge dimensions (RW, BH and PH) were noted in the <1mm BT group. Histomorphometrically, the DBBMC-EMD test group showed significantly increased new bone formation (%NB): (control=16.5±6.9% cf.; test=45.1±8.8%) with less residual graft (%RG): (control=36.8±8.8% cf.; test=20.3±7.2%) compared to the DBBMC control group. Both DBBMC alone and DBBMC-EMD treated sites 4months after extraction lost RW but showed no significant change in BH or PH. Irrespective of treatment, maxillary anterior teeth with thick initial buccal walls (≥1mm) exhibited less alveolar ridge reduction 4months after treatment. The addition of EMD to DBBMC resulted in more new bone formation in the test group.

Effect of mandibular residual ridge regularization on peri-implant wound healing when narrow diameter implants are used as overdenture retainers

Statement of problemAlveolar ridge regularization involves the smoothing and minimal reduction of rough alveolar bone ridge to achieve adequate bone thickness around the implant. The effect of this procedure on peri-implant health is unclear. PurposeThe purpose of this clinical study was to evaluate whether bone regularization affects the clinical and biological parameters of peri-implant health when narrow diameter implants are placed as mandibular implant overdenture retainers during initial healing and after occlusal loading. Material and methodsThe need for mandibular ridge regularization in the anterior mandibular region was analyzed before the placement of 2 implants (2.9×10 mm, Facility; Neodent) in 21 participants provided with mandibular overdentures. Primary stability was measured by the insertion torque and implant stability quotient (ISQ). Clinical and biological evaluations measuring the plaque index, presence of calculus, probing depth, bleeding on probing index, gingival index, secondary stability (ISQ), and interleukine-1β (IL-1β) and tumor necrosis factor-α (TNF-α) concentrations in peri-implant crevicular fluid were measured during osseointegration on days 7, 15, 30, 60, and 90 and after loading on day 180 after implant placement. Multilevel mixed-effects linear regression analysis and the Kaplan–Meier test were used to analyze the data (α=.05). ResultsThe ISQ values showed significant differences on days 7 (P<.001) and 15 (P=.002) with higher values and on day 180 (P=.008) with a lower value compared with the baseline value in the ridge regularization group. Additionally, a significant decrease in probing depth was observed on days 60 (P=.008) and 180 (P=.027) compared with that on day 15 after implant placement. In the nonridge regularization group, significant decreases in probing depth were observed on days 30 and 180. Moreover, TNF-α levels in this group were significantly lower on days 30 (P=.001), 60, 90, and 180 (P<.001) when compared with the value on day 7 (P<.001). The ridge regularization group presented with significant differences in TNF-α and IL-1β levels on days 60 (P=.004) and 30 (P=.007), respectively, when compared with the values on day 7. The ISQ and probing depth in the ridge regularization group were associated with changes in TNF-α and IL-1β levels; furthermore, bone type, duration of edentulism, and mandibular bone atrophy were correlated with the clinical outcomes and TNF-α release. The implant survival rate was 67% in the nonridge regularization group and 100% in the ridge regularization group. ConclusionsMandibular ridge regularization appeared to be beneficial for peri-implant healing during the early stages and after 3 months of occlusal loading in patients with an atrophic ridge, prolonged time since edentulism, and poor bone quality.

Advantage of the regenerative potentials of the periosteum especially in children, Oghara experience: A case series

The periosteum is a composite tissue comprising an outer protective fibrovascular layer and an inner cambium regenerative pluripotent layer. The regenerative function of periosteum has been put to clinical use by dental surgeons to manage alveolar ridge reduction and by tissue engineers to produce autologous micrograft and collagen used to manage complex wounds and scars. The essence of this study is to add to the body of knowledge on clinical use of periosteum to treat bone defects from the orthopaedic perspective. We highlight a case series to demonstrate the use of periosteum in managing bone defects caused by benign bone tumour, chronic osteomyelitis, tibial hemimelia and traumatic bone loss of the distal tibia in Delta State University Teaching Hospital, Oghara. Treatment of bone defects by this means is cost effective and the outcome is very satisfactory.&#x0D; Key words: Periosteum, mesenchymal stem cells, bone defects, distraction histiogenesis.

Fully Digital Workflow with Magnetically Connected Guides for Full-Arch Implant Rehabilitation Following Guided Alveolar Ridge Reduction.

This technique report describes a fully digital workflow in which two surgical guides (i.e. one for alveolar bone reduction and the other for implant placement) are magnetically connected to ensure stability during full-arch implant surgery following guided bone reduction. Digital prosthesis design as well as virtual bone reduction and implant planning are developed from the superimposition of facial, intraoral and CBCT scans. With this technique, different surgical guides and interim poly(methylmethacrylate) (PMMA) fixed prosthesis are precisely connected with magnets after being digitally designed and 3D-printed. As a result, such magnetic connection allows for satisfactory stability of the implant surgical guide, as well as of the interim fixed PMMA fixed prosthesis during capture of screw-retained abutments.

Lentiviral‑mediated Shh reverses the adverse effects of high glucose on osteoblast function and promotes bone formation via Sonic hedgehog signaling.

Patients with diabetes tend to have an increased incidence of osteoporosis, which may be associated with hyperglycemia; however, the pathogenic mechanisms governing this interaction remain unknown. The present study sought to investigate whether elevated extracellular glucose levels of bone mesenchymal stem cells (BMSCs) could influence osteoblastic differentiation and whether the intracellular Sonic hedgehog (Shh) pathway could adjust the effects. Furthermore, to verify the results in vivo, a rat tooth extraction model was constructed. BMSCs were incubated in eight types of culture medium, including low glucose (LG), LG + lentivirus (Lenti), LG + Lenti-small interfering RNA (Lenti-siRNA), LG + Lenti-Shh, high glucose (HG), HG + Lenti, HG + Lenti-siRNA and HG + Lenti-Shh. The lentiviral transfection efficiency was observed using a fluorescence microscope; protein and mRNA expression was detected by western blotting and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The matrix mineralization and alkaline phosphatase (ALP) activity of BMSCs were examined by Alizarin red staining and ALP activity assays, respectively. The expression of osteogenesis-related genes in BMSCs were quantified by RT-qPCR. The alveolar ridge reduction was measured and histological sections were used to evaluate new bone formation in the tooth socket. With high concentrations of glucose, Shh expression, matrix mineralization nodules formation, ALP activity and the levels of bone morphogenic protein 4 (BMP4), bone sialoprotein (BSP) and osteopontin (OPN) expression were greatly reduced compared with LG and corresponding control groups. Whereas activated Shh signaling via Lenti-Shh could increase the number of matrix mineralization nodules, ALP activity, and the expression levels of BMP4, BSP and OPN in BMSCs. Additionally, in vivo assays demonstrated that Lenti-Shh induced additional bone formation. Collectively, the results of the present study indicated that HG inhibited the Shh pathway in osteoblasts and resulted in patterning defects during osteoblastic differentiation and bone formation, while the activation of Shh signaling could suppress these deleterious effects.

Socket healing with and without immediate implant placement.

The aim of the present review was to describe the studies produced in Latin America that contributed to the elucidation of the effect of tooth extraction with and without immediate implant installation. An electronic search was conducted in MEDLINE (PubMed), Scopus, Scielo, Lilacs, and Embase to include clinical and experimental (animal) studies on immediate implants. The studies selected had to fulfill the following inclusion criteria: (i) to present clinical and/or histological data on socket healing with or without immediate implant installation; (ii) to be approved by a Latin American Ethic Committee or comparable; and (iii) to include at least one author from a Latin American institution or to be conducted in a Latin America institution. Latin American studies that fulfilled these criteria demonstrated that immediate implant installation was conducive for predictable osseointegration and high survival rates but failed to prevent bone modeling and dimensional reduction of the alveolar ridge. In addition, it was also shown that regenerative approaches, including hard and soft tissue grafts at the time of immediate implant placement, may be beneficial to compensate for the alveolar ridge reduction. Regenerative approaches immediately after tooth extraction may decrease the amount of dimension reduction of the alveolar ridge.

Virtually guided alveolar ridge reduction combined with computer-aided implant placement for a bimaxillary implant-supported rehabilitation: A clinical report

Insufficient crown height space, particularly in the interforaminal region of edentulous ridges with knife-edge morphology, may prevent successful prosthetic rehabilitation. Such conditions require osteoplasty, which might complicate computer-guided implant placement. This clinical report illustrates the treatment of a patient with complete edentulism rehabilitated with a mandibular implant-supported fixed dental prosthesis by using a virtually guided approach. Both alveolar ridge reduction and prosthetically driven implant insertions were computer-guided by surgical stents to increase accuracy and predictability. This approach enabled the immediate loading of the implants with an interim prosthesis before the delivery of a definitive screw-retained fixed prosthesis. At the 1-year follow-up visit, clinical and radiographic examination revealed a stable outcome.

A retrospective evaluation of 128 socket-shield cases in the esthetic zone and posterior sites: Partial extraction therapy with up to 4 years follow-up.

Tooth loss results in an inevitable alveolar ridge reduction. This has established a cautionary approach to extract, wait, augment, and insert the implant, in lieu of immediate placement. However, saving the tooth or part of it whenever possible is more conservative and supports the vital periodontal tissue buccofacial to an implant. The purpose of this cases series was to report on implant survival using this technique in a large cohort of patients at mid-term follow-up. A private practice patient database was searched for all patients having received socket-shield treatment in conjunction with immediate implant placement. Of the results returned, 128 met the inclusion criteria of ≥12 months from date of restoration, or failing prior to definitive restoration. These patients were recalled for evaluation of the restored implants up to 4years post-treatment. Seventy immediate implants with socket-shields were placed in female patients and 58 in males, age range 24-71 (mean 39 years). The distribution of sites treated were: maxillary incisors (64%), premolars (22%), canines (14%); maxilla (89.9%), mandible (10.1%). 123/128 implants osseointegrated and survived 1-4 years following restoration (survival rate 96.1%). A combined complication rate of 25/128 implants occurred (19.5%). Five implants failed to osseointegrate and were removed. The remaining 20 complications were all managed or observed without management, with implants surviving at mid-term follow-up. Notwithstanding technique sensitivity and the need for randomized control studies, this case series demonstrates that the socket-shield performs competitively when compared to implant survival rates in both conventional immediate and delayed implant placement.

Combining guided alveolar ridge reduction and guided implant placement for all-on-4 surgery: A clinical report

Immediate restoration with the all-on-4 concept has become an established treatment option. The technique involves alveoloplasty before implant placement to provide space for the prosthetic components and to provide a platform on which dental implants can be placed in clinical situations where a knife-edge alveolar ridge is present. Guided implant surgery involves the fabrication of a guide by using data from cone-beam computed tomography (CBCT) and implant surgery performed without flap reflection. In the presented technique, a printed cast based on a CBCT is used to fabricate a guide for both alveolar ridge reduction and guided implant surgery. The alveolar ridge reduction and implant surgery are virtually simulated in the laboratory to provide space for the restorative components and to avoid critical anatomic landmarks (mental nerve or perforation of the lingual mandibular plate). The described surgical guide enables guided alveolar ridge reduction and guided implant placement where the implant placement performed in the laboratory can be duplicated clinically during implant surgery.

Histologic and histomorphometric evaluation of two grafting materials Cenobone and ITB-MBA in open sinus lift surgery.

Aims and Objectives:Alveolar ridge reduction caused after tooth extraction can be minimized through ridge preservation and application of graft materials. The aim of this study was to compare the histologic and histomorphometric aspects of bone particulated allografts, Cenobone and ITB-MBA, in the reconstruction of vertical alveolar ridge after maxillary sinus augmentation.Materials and Methods:This clinical trial was performed among 20 patients. The participants were randomly divided into two groups of 10 participants. The first group received Cenobone and the second group received ITB-MBA. Tissue samples were prepared 6 months later at the time of implant installation and after successful maxillary sinus floor augmentation. Tissue sections were examined under a light microscope. The data were analyzed by Chi-square and t-test.Results:The mean trabecular thickness of the samples in the Cenobone group was 13.61 ± 7.47 μm compared to 13.73 ± 7.37 μm in the ITB-MBA group (P = 0.93). A mild inflammation process (Grade 1) was detected in both the groups. The amount of remaining biomaterial in the Cenobone group was estimated to be 8 ± 19% vs. 7 ± 12% in the ITB-MBA group (P = 0.30). Bone formation was reported 49.71% in the Cenobone group vs. 40.76% in the ITB-MBA group (P = 0.68). The mean newly formed vessel in the Cenobone group was 0.64 ± 0.7 vs. 1.5 ± 2.3 in the ITB-MBA group (P = 0.14).Conclusions:There was no significant difference between the two groups of patients regarding trabecular thickness, remaining biomaterial allograft, and the density of blood vessels after sinus floor elevation; hence, there was no difference between the two groups regarding implant outcome. More designed studies as randomized controlled trials and controlled clinical trials, which evaluate the long-term implant outcome; comparing the different bone graft materials is also required to improve evidence on survival and success rate.

Reduction of Adipose Tissue Formation by the Controlled Release of BMP-2 Using a Hydroxyapatite-Coated Collagen Carrier System for Sinus-Augmentation/Extraction-Socket Grafting.

The effects of hydroxyapatite (HA)-coating onto collagen carriers for application of recombinant human bone morphogenetic protein 2 (rhBMP-2) on cell differentiation in vitro, and on in vivo healing patterns after sinus-augmentation and alveolar socket-grafting were evaluated. In vitro induction of osteogenic/adipogenic differentiation was compared between the culture media with rhBMP-2 solution and with the released rhBMP-2 from the control collagen and from the HA-coated collagen. Demineralized bovine bone and collagen/HA-coated collagen were grafted with/without rhBMP-2 in sinus-augmentation and tooth-extraction-socket models. Adipogenic induction by rhBMP-2 released from HA-coated collagen was significantly reduced compared to collagen. In the sinus-augmentation model, sites that received rhBMP-2 exhibited large amounts of vascular tissue formation at two weeks and increased adipose tissue formation at eight weeks; this could be significantly reduced by using HA-coated collagen as a carrier for rhBMP-2. In extraction-socket grafting, dimensional reduction of alveolar ridge was significantly decreased at sites received rhBMP-2 compared to control sites, but adipose tissue was increased within the regenerated socket area. In conclusion, HA-coated collagen carrier for Escherichia coli-derived rhBMP-2 (ErhBMP-2) may reduce in vitro induction of adipogenic differentiation and in vivo adipose bone marrow tissue formation in bone tissue engineering by ErhBMP-2.

Use of Transalveolar Sutures to Maintain Vestibular Depth and Keratinized Tissue Following Alveolar Ridge Reduction and Implant Placement for Mandibular Prosthesis

Reconstruction of the totally edentulous patient with dental implants has become a routine treatment with predictable outcomes. Firm keratinized tissue surrounding the implants and adequate vestibular depth are among the determining factors for long-term implant success. In the staged approach of mandibular implant reconstruction, adequate vestibular depth as well as attached gingiva surrounding the implants can be readily established at the time of implant placement or when the implants are uncovered. However, in cases when extractions and necessary mandibular ridge reduction to create adequate width are done immediately prior to implant placement, maintaining adequate keratinized tissue around the implants, as well as preventing prolapse of the vestibule can present a challenging situation. The aim of this report is to present a technique that allows the surgeon to stabilize vestibular depth and at the same time position the flaps around the implants and preserve the attached gingiva.

Socket Preservation: Allograft vs. Alloplast

Background: The volume shrinkage of the alveolar ridge might be minimized by the ridge preservation stagesand applied biomaterials, after tooth extraction. Objectives: The aim of this study is to compare alloplastic with allograft in terms of preservation and bone regeneration of the alveolar ridge after tooth extraction. Materials and Methods: This study clinically assessed this issue via the Split Mouth method which assessed 10 dental sockets filled with alloplasts and 9 others with allografts postextraction. The effectiveness of each material was clinically and histologically processed. The alveolar ridge width was measured by a gauge, before filling the socket and 2 months postextraction when inserting the dental implant. The histological process of bone samples were observed under light microscope at the time of fixture insertion to evaluate live and dead bone, trabecular, amorphous and non- osteoblastic. The changes in two groups in terms of the quantity underwent T-Test examination and the quality of bone regeneration was assessed using MANN-U-WHITNEY test. IRB and ethical approval was granted for our study. Results: Minimal reduction of alveolar ridge widths were observed in both groups (reduction of alveolar ridge in the allograft group: 0.61 mm ± 1.06 and in the alloplast group: 0.85 mm ± 0.88) but the difference was not significant statistically (P=0.6); no significant differences were noted in vital (P=0.9), nonvital (P<0.8), trabecular (P<0.7) or amorphous (P<0.4) bone. Conclusion: Both materials were equal in terms of the quantity and the quality of osteoblasts and both were the same in terms of live and dead bone. No major differences in the regenerated bone could be found between these two groups.

Use of Transalveolar Sutures to Maintain Vestibular Depth and Manipulate Keratinized Tissue Following Alveolar Ridge Reduction and Implant Placement for Mandibular Prosthesis

Reconstruction of the totally edentulous patient with dental implants has become routine treatment with predictable outcomes. Firm keratinized tissue surrounding the implants and adequate vestibular depth are among the determining factors for long-term implant success. In the staged approach of mandibular implant reconstruction, adequate vestibular depth and attached gingiva surrounding the implants can be readily established at the time of implant placement or when the implants are uncovered. However, when extractions and necessary mandibular ridge reduction to create adequate width are performed immediately before implant placement, maintaining adequate keratinized tissue around the implants and preventing prolapse of the vestibule can present a challenging situation. This report presents a technique that allows the surgeon to stabilize vestibular depth and at the same time position the flaps around the implants and preserve the attached gingiva.

Dimensional alterations of extraction sites after different alveolar ridge preservation techniques – a volumetric study

The aim of this randomized controlled clinical study was to assess soft tissue contour changes after different alveolar ridge preservation procedures. Following tooth extraction, 30 patients were randomly assigned to the following treatments (Tx) - Tx 1: xenogenic bone substitute (pre-hydrated collagenated cortico-cancellous porcine bone) and free gingival graft; Tx 2: free gingival graft alone; Tx 3: xenogenic bone substitute; Tx 4: no further treatment (control). Impressions were obtained before tooth extraction (baseline) and 4 months after surgery. Cast models were optically scanned, digitally superimposed and horizontal measurements of the contour alterations between time points were performed using digital imaging analysis. All groups displayed contour shrinkage at the buccal aspect ranging from a mean horizontal reduction of -0.8±0.5mm (Tx 1) to -2.3±1.1mm (control). Statistically significant differences were found between Tx 1 and Tx 4 as well as Tx 2 and Tx 4. A significant positive influence of the free gingival graft on the maintenance of the ridge width was recorded (p<0.001). In this study, alveolar ridge preservation techniques were not able to entirely compensate for alveolar ridge reduction. Covering the orifice of the extraction socket with a free gingival tissue graft seems to have the potential to limit but not avoid the post-operative external contour shrinkage based on optical scans.

Alveolar ridge reduction after tooth extraction in adolescents: An animal study

ObjectiveThe mechanism for tooth extraction induced residual alveolar ridge reduction (RRR) during adolescence is poorly understood. This study investigated the alveolar bone morphology, growth, resorption and functional loading at normal and extraction sites using an adolescent pig model. DesignSixteen 3-month-old pigs were divided into two groups – immediate post-extraction (IE) and 6-week post-extraction (SE). The IE group received an extraction of one deciduous mandibular molar, immediately followed by a final experiment to record masseter muscle EMGs and strains from the buccal surface of the extraction and contralateral non-extraction sites during function (mastication). The SE group was given the same tooth extraction, then kept for 6 weeks before the same final functional recording as the IE group. Both groups also received baseline (pre-extraction) EMGs and fluorescent vital stains 10 and 3 days before the final functional recording. Immediately after the final functional recording, animals were euthanized and alveolar bone specimens from extraction and contralateral non-extraction sites were collected and used to analyse alveolar bone morphology, apposition and resorption based on fluorescent and hematoxylin and eosin stained histological sections. ResultsAt control sites (IE-extraction, IE-non-extraction and SE-non-extraction), the alveolar ridges grew gingivally and buccally. Bone formation characterized the buccal surface and lingual bundle bone, whereas resorption characterized the lingual surface and buccal bundle bone. The SE-extraction sites showed three major alterations: convergence of the buccal and lingual gingival crests, loss of apposition on the lingual bundle bone, and decelerated growth at the entire buccal surface. These alterations likely resulted from redirected crestal growth as part of the socket healing process, loss of tongue pressure to the lingual side of the teeth which normally provides mechanical stimulation for dental arch expansion, and masticatory underloading during the initial post-extraction period, respectively. ConclusionsThese data indicate that the initial phase of RRR in adolescents is a product of modified growth, not resorption, possibly because of decreased mechanical stimulation at the extraction site.