Healing patterns of alveolar bone following ridge preservation procedures.

OBJECTIVES: Examine the histomorphometric bone composition, following alveolar ridge preservation techniques and unassisted socket healing. MATERIALS AND METHODS: Forty-two patients (42) requiring a single rooted tooth extraction were randomly allocated into three groups (n = 14 per group): Group 1: Guided Bone Regeneration (GBR) using deproteinised bovine bone mineral (DBBM) and a porcine collagen membrane; Group 2: Socket Seal (SS) technique using DBBM and a porcine collagen matrix; Group 3: Unassisted socket healing (Control). Trephined bone biopsies were harvested following a 4-month healing period. Forty-two samples underwent Back-Scattered Electrons -Scanning Electron Microscopy (BSE-SEM) imaging, with 15 samples examined using Xray Micro-Tomography (XMT) (n = 6 for each GBR/SS and n = 3 Control). Images were analysed to determine the percentage (%) of connective tissue, new bone formation, residual DBBM particles and direct bone to DBBM particle contact (osseointegration). RESULTS: BSE-SEM analysis demonstrated that new bone formation was higher in the Control (45.89% ± 11.48) compared to both GBR (22.12% ± 12.7/p < .004) and SS (27.62% ± 17.76/p < .005) groups. The connective tissue percentage in GBR (49.72% ± 9), SS (47.81% ± 12.57) and Control (47.81% ± 12.57) groups was similar. GBR (28.17% ± 16.64) and SS (24.37% ± 18.61) groups had similar levels of residual DBBM particles. XMT volumetric analysis indicated a lower level of bone and DBBM particles in all test groups, when matched to the BSE-SEM area measurements. Osseointegration levels (DBBM graft and bone) were recorded at 35.66% (± 9.8) for GBR and 31.18% (± 19.38) for SS. CONCLUSION: GBR and SS ARP techniques presented with less bone formation when compared to unassisted healing. GBR had more direct contact/osseointegration between the DBBM particles and newly formed bone.

Is alveolar ridge preservation an overtreatment?

The morphology and dimensions of the postextraction alveolar ridge are important for the surgical and restorative phases of implant treatment. Adequate new bone formation and preservation of alveolar ridge dimensions following extraction will facilitate installation of the implant in a restorative position, while preservation of soft tissue contour and volume is essential for an aesthetic and implant-supported restoration with healthy peri-implant tissues. Alveolar ridge preservation (ARP) refers to any procedure that aims to: (i) limit dimensional changes in the alveolar ridge after extraction facilitating implant placement without additional extensive bone and soft tissue augmentation procedures (ii) promote new bone formation in the healing alveolus, and (iii) promote soft tissue healing at the entrance of the alveolus and preserve the alveolar ridge contour. Although ARP is a clinically validated and safe approach, in certain clinical scenarios, the additional clinical benefit of ARP over unassisted socket healing has been debated and it appears that for some clinicians may represent an overtreatment. The aim of this critical review was to discuss the evidence pertaining to the four key objectives of ARP and to determine where ARP can lead to favorable outcomes when compared to unassisted socket healing.

Alveolar ridge preservation with guided bone regeneration or socket seal technique. A randomised, single-blind controlled clinical trial.

OBJECTIVES: To compare radiographic bone changes, following alveolar ridge preservation (ARP) using Guided Bone Regeneration (GBR), a Socket Seal (SS) technique or unassisted socket healing (Control). MATERIAL AND METHODS: Patients requiring a single rooted tooth extraction in the anterior maxilla, were randomly allocated into: GBR, SS and Control groups (n= 14/). Cone Beam Computed Tomography (CBCT) images were recorded post-extraction and at 4 months, the mid-buccal and mid-palatal alveolar ridge heights (BARH/PARH) were measured. The alveolar ridge width, cross-sectional socket and alveolar-process area changes, implant placement feasibility, requirement for bone augmentation and post-surgical complications were also recorded. RESULTS: BARH and PARH was found to increase with the SS (0.65 mm ± 1.1/0.65 mm ± 1.42) techniques, stabilise with GBR (0.07 mm ± 0.83/0.86 mm ±1.37) and decrease in the Control (-0.52 mm ± 0.8/-0.43 mm ± 0.83). Statistically significance was found when comparing the GBR and SS BARH (p = .04/.005) and GBR PARH (p = .02) against the Control. GBR recorded the smallest reduction in alveolar ridge width (-2.17 mm ± 0.84), when compared to the Control (-2.3 mm ± 1.11) (p = .89). A mid-socket cross-sectional area reduction of 4% (-2.27 mm2  ± 11.89), 1% (-0.88 mm2  ± 15.48) and 13% (-6.93 mm2  ± 8.22) was found with GBR, SS and Control groups (GBR vs. Control p = .01). The equivalent alveolar process area reduction was 8% (-7.36 mm2  ± 10.45), 6% (-7 mm2  ± 18.97) and 11% (-11.32 mm2  ± 10.92). All groups supported implant placement, with bone dehiscence noted in 57% (n = 4), 64%(n = 7) and 85%(n = 12) of GBR, SS and Control cases (GBR vs. Control p = .03). GBR had a higher risk of swelling and mucosal colour change, with SS associated with graft sequestration and matrix breakdown. CONCLUSION: GBR ARP was found to be more effective at reducing radiographic bone dimensional changes following tooth extraction.

Hard and soft tissue changes following alveolar ridge preservation: a systematic review.

OBJECTIVE: Two focused questions were addressed within this systematic review. Q1) What is the effect of alveolar ridge preservation on linear and volumetric alveolar site dimensions, keratinised measurements, histological characteristics and patient-based outcomes when compared to unassisted socket healing. Q2) What is the size effect of these outcomes in three different types of intervention (guided bone regeneration, socket grafting and socket seal). MATERIALS AND METHODS: An electronic search (MEDLINE, EMBASE, Cochrane Central Register LILACS, Web of Science) and hand-search was conducted up to June 2015. Randomised controlled trials (RCT) and controlled clinical trials (CCT); with unassisted socket healing as controls: were eligible in the analysis for Q1. RCTs, CCTs and large prospective case series with or without an unassisted socket healing as control group were eligible in the analysis for Q2. RESULTS: Nine papers (8 RCTs and 1 CCTs) were included in the analysis for Q1 and 37 papers (29 RCTs, 7 CCTs and 1 case series) for Q2. The risk for bias was unclear or high in most of the studies. Q1: the standardised mean difference (SMD) in vertical mid-buccal bone height between ARP and a non-treated site was 0.739 mm (95% CI: 0.332 to 1.147). The SMD when proximal vertical bone height and horizontal bone width was compared was 0.796mm (95% CI: -1.228 to 0.364) and 1.198 mm (95% CI: -0.0374 to 2.433). Examination of ARP sites revealed significant variation in vital and trabecular bone percentages and keratinised tissue width and thickness. Adverse events were routinely reported, with three papers reporting a high level of complications in the test and control groups and two papers reporting greater risks associated with ARP. No studies reported on variables associated with the patient experience in either the test or the control group. Q2: A pooled effect reduction (PER) in mid-buccal alveolar ridge height of -0.467 mm (95% CI: -0.866 to -0.069) was recorded for GBR procedures and -0.157 mm (95% CI: -0.554 to 0.239) for socket grafting. A proximal vertical bone height reduction of -0.356 mm (95% CI: -0.490 to -0.222) was recorded for GBR, with a horizontal dimensional reduction of -1.45 mm (95% CI: -1.892 to -1.008) measured following GBR and -1.613 mm (95% CI: -1.989 to -1.238) for socket grafting procedures. Five papers reported on histological findings after ARP. Two papers indicated an increase in the width of the keratinised tissue following GBR, with two papers reporting a reduction in the thickness of the keratinised tissue following GBR. Histological examination revealed extensive variations in the treatment protocols and biomaterials materials used to evaluate extraction socket healing. GBR studies reported a variation in total bone formation of 47.9 ± 9.1% to 24.67 ± 15.92%. Post-operative complications were reported by 29 papers, with the most common findings soft tissue inflammation and infection. CONCLUSION: ARP results in a significant reduction in the vertical bone dimensional change following tooth extraction when compared to unassisted socket healing. The reduction in horizontal alveolar bone dimensional change was found to be variable. No evidence was identified to clearly indicate the superior impact of a type of ARP intervention (GBR, socket filler and socket seal) on bone dimensional preservation, bone formation, keratinised tissue dimensions and patient complications.

Does ridge preservation following tooth extraction improve implant treatment outcomes: a systematic review: Group 4: Therapeutic concepts & methods.

OBJECTIVE: (1) Primary focused question (Q1): to evaluate the effect of alveolar ridge preservation (ARP) on implant outcomes (implant placement feasibility, need for further augmentation, survival/success rates, marginal bone loss) compared with unassisted socket healing (USH) and (2) secondary focused question (Q2): to estimate the size effects (SE) of these outcomes in three different interventions (GBR, socket filler, socket seal). MATERIAL AND METHODS: Electronic (MEDLINE, EMBASE, Cochrane Central Register LILACS; Web of Science) and hand search was conducted up to July 2014. Randomised controlled trials (RCT), controlled clinical trials (CCT) and prospective cohort studies with USH as controls were eligible in the analysis for Q1. RCTs, CCTs and prospective case series, with or without USH as control, were eligible for Q2. RESULTS: Ten (8 RCTs, 2 CCTs) and 30 studies (21 RCTs, 7 CCTs, 2 case series) were included in the analysis for Q1 and Q2, respectively. The risk for bias was unclear or high in most of them. Q1: Implant placement was feasible in ARP-treated and USH sites. These implants presented similar survival/success rates and marginal bone levels. The need for further augmentation decreased when ARP was performed (Relative risk: 0.15, 95% CI: 0.07-0.3). Q2: The SE for implant placement feasibility was 98.5% (95% CI: 96.4-99.6) in GBR and 96.2 (95% CI: 93.1-98.2) in socket filler group. The SE for need for further augmentation was 11.9 (95% CI: 5.6-19.9) for GBR and 13.7% (95% CI: 5.0-25.6) for socket filler groups. GBR and socket filler presented similar SE for survival/success rates and average marginal bone loss. Limited data were available for implant-related outcomes in sites treated with socket seal. CONCLUSIONS: There is limited evidence to support the clinical benefit of ARP over USH in improving implant-related outcomes despite a decrease in the need for further ridge augmentation during implant placement. Similar implant placement feasibility, survival/success rates and marginal bone loss should be anticipated following ARP or USH. Currently, it is not clear which type of ARP intervention has a superior impact on implant outcomes.