Bone healing dynamics at buccal peri-implant sites

Immediate Implantation with Autologous Mineralized Dentin Graft versus Deproteinized Bovine Bone as Space-Filling Substitute in Maxillary Anterior Zone: Retrospective Radiological and Clinical Study

Background/Objectives: Various bone substitutes have been recommended to augment the horizontal gap following immediate implantation. The purpose of this study was to compare the effectiveness of an autogenous mineralized dentin graft or a deproteinized bovine bone in horizontal gap augmentation following immediate implant placement in the maxillary anterior region. Methods: A total of 110 patients underwent tooth extraction followed by immediate implant placement. The patients were divided into two groups. The first group received an autogenous mineralized dentin graft (the test group) while the second group received a deproteinized bovine bone (the control group) to augment the horizontal gap. Preoperative (T0), immediate postoperative (T1), and 1-year postoperative (T2) cone beam computed tomography scans were taken from all the patients. Linear measurements were recorded 1 mm (R1) and 5 mm (R2) points apical to the implant platform at both T1 and T2 time intervals. Pink Esthetic Scores and prosthetic complications were evaluated as well. Results: There were 57 patients with a mean age of 45.42 ± 9.86 (range 24-63 years) selected as the test group and 53 patients with a mean age of 40.28 ± 11.69 (range 20-63 years) as the control group. The mean reduction in the buccal bone plate at R1 was 6.39 ± 3.78% in the test group and 6.99 ± 5.01% in the control group (p > 0.05). The mean reduction in the buccal bone plate at R2 was 5.46 ± 4.98% in the test group and 6.77 ± 7.60% in the control group (p < 0.05). The PES and prosthetic-related complications were shown to be negligible between the groups (p > 0.05). Conclusions: The efficiency of using an autogenous mineralized dentin graft for horizontal gap augmentation showed similar results in comparison to using a deproteinized bovine bone in relation to buccolingual socket reduction following immediate implantation.

Local delivery of pamidronate with collagen matrix mitigates buccal bone resorption following immediate implant placement - An experimental in vivo study

AIMS

The aim of this experimental in vivo pilot study was to evaluate the effect of the local delivery of pamidronate within a collagen membrane on the changes in the buccal soft and hard tissue dimensions at the time of immediate implant placement and whether this effect was influenced by the placement of bone substitutes.

METHODS

In six beagle dogs, the distal roots of the third and fourth premolars were extracted, and immediate implants were placed. Treatment groups were randomly allocated to each socket: (i) covering the buccal bone with pamidronate-soaked collagen membrane (BP group), (ii) filling the gap defect with synthetic bone substitute (BS group), (iii) filling the gap defect with synthetic bone substitute and covering the buccal bone with pamidronate soaked collagen membrane (BP/BS group), (iv) no treatment (control group). Intraoral scanning was performed immediately after the surgery and at 20 weeks. Histomorphometric and micro-computed tomography (CT) outcomes were evaluated at 20 weeks.

RESULTS

The micro CT analysis demonstrated that the BP group showed no apparent difference in vertical bone level with residual mesial root area, while control group showed significant buccal bone resorption at the implant site. The histomorphometric analysis demonstrated that the vertical bone level of buccal plate was significantly differed between the BP and control group (0.34 ± 0.93 and 1.27 ± 0.56 mm, respectively; p = .041). There was no statistically significant difference in the horizontal ridge width (HRW 1, 2, 3) among the groups. Also, the thickness, height and buccal contours of the soft tissue did not reveal significant changes among the groups.

CONCLUSION

The local delivery of pamidronate to the outer surface of the buccal wall at the time of immediate implant placement effectively limits buccal bone resorption. The results from the present investigation should be interpreted with caution, as well as its clinical translatability. Further investigation is needed to understand the pamidronate binding and releasing kinetic, as well as the ideal carrier of this drug for its topical application.

Effect of mineralized dentin matrix on the prognosis of bone defect and retained root after coronectomy

OBJECTIVE

To investigate the impact of mineralized dentin matrix (MDM) on the prognosis on bone regeneration and migration of retained roots after coronectomy.

MATERIALS AND METHODS

Patients were divided into three groups based on the type of bone graft after coronectomy: Group C (n = 20, collagen), Group T (n = 20, tricalcium phosphate (TCP) + collagen), and Group D (n = 20, MDM + collagen). CBCT scans, conducted immediately and 6 months after surgery, were analyzed using digital software. Primary outcomes, including changes in bone defect depth and retained root migration distance, were evaluated 6 months after surgery.

RESULTS

After 6 months, both Groups D and T exhibited greater reduction of the bone defect and lesser retained root migration than Group C (p < 0.001). Group D had greater regenerated bone volume in the distal 2 mm (73 mm3 vs. 57 mm3, p = 0.011) and lesser root migration (2.18 mm vs. 2.96 mm, p < 0.001) than Group T. The proportion of completely bone embedded retained roots was also greater in Group D than in Group C (70.0% vs. 42.1%, p = 0.003).

CONCLUSIONS

MDM is an appropriate graft material for improving bone defect healing and reducing retained root migration after coronectomy.

CLINICAL RELEVANCE

MDM is an autogenous material prepared chairside, which can significantly improve bone healing and reduce the risk of retained root re-eruption. MDM holds promise as a routine bone substitute material after M3M coronectomy.

Evaluation of buccal bone resorption in immediate implant placement in thin versus thick buccal bone plates: An 18-month follow-up prospective cohort study

OBJECTIVES

The current guidelines recommend that immediate implants be placed in patients with thick (>1 mm) buccal bone due to the inevitable tissue remodeling that follows tooth extraction. The aim of the current study was to investigate the effect of buccal bone thickness on bone resorption in immediate implant placement and compare two measuring techniques of the aforementioned resorption.

MATERIALS

The present study was designed as a prospective nonrandomized, controlled clinical trial. A total of 30 implants were split between the two study arms, thin buccal bone and thick buccal bone. The primary outcome was to assess vertical bone changes radiographically by cone beam scans preoperatively, at 2 months and 18 months after implant placement in patients with thin and thick buccal plate. Secondary outcomes included the change in the thickness of the buccal bony plate, marginal bone loss, and pink esthetic score.

RESULTS

Only 26 implants were statistically analyzed as one early failure was observed in each group. Furthermore, 2 patients of the thick group withdrew from the study. Cone beam computed tomography measurements revealed that at 2 months the vertical bone loss was 1.09 for the thin group and 0.85 for the thick group. The buccal bone plate resorption of the thin group was 0.39 mm while it was 0.52 mm for the thick group. The buccal bone plate was 1.25 mm in the thin group and 1.88 mm in the thick group. The PES did not show any significant difference with very good esthetic results.

CONCLUSION

Within the limitations of the current study, the amount of buccal bone plate resorption and the subsequent thickness obtained after implantation in both groups suggest successful long-term results. The two measuring techniques have proven to be comparable and reliable in the measurement of buccal bony plate changes. https://classic.

CLINICALTRIALS

gov/ct2/results?cond=&term=NCT04731545&cntry=EG&state=&city=&dist=.

Reconstruction of Segmental Bone Defect in Canine Tibia Model Utilizing Bi-Phasic Scaffold: Pilot Study

The reunion and restoration of large segmental bone defects pose significant clinical challenges. Conventional strategies primarily involve the combination of bone scaffolds with seeded cells and/or growth factors to regulate osteogenesis and angiogenesis. However, these therapies face inherent issues related to immunogenicity, tumorigenesis, bioactivity, and off-the-shelf transplantation. The biogenic micro-environment created by implanted bone grafts plays a crucial role in initiating the bone regeneration cascade. To address this, a highly porous bi-phasic ceramic synthetic bone graft, composed of hydroxyapatite (HA) and alumina (Al), was developed. This graft was employed to repair critical segmental defects, involving the creation of a 2 cm segmental defect in a canine tibia. The assessment of bone regeneration within the synthetic bone graft post-healing was conducted using scintigraphy, micro-CT, histology, and dynamic histomorphometry. The technique yielded pore sizes in the range of 230-430 μm as primary pores, 40-70 μm as secondary inner microchannels, and 200-400 nm as tertiary submicron surface holes. These three components are designed to mimic trabecular bone networks and to provide body fluid adsorption, diffusion, a nutritional supply, communication around the cells, and cell anchorage. The overall porosity was measured at 82.61 ± 1.28%. Both micro-CT imaging and histological analysis provided substantial evidence of robust bone formation and the successful reunion of the critical defect. Furthermore, an histology revealed the presence of vascularization within the newly formed bone area, clearly demonstrating trabecular and cortical bone formation at the 8-week mark post-implantation.

Critical review on bone grafting during immediate implant placement

In the last 20 years, immediate implant placement has been proposed as a predictable protocol to replace failing teeth. The research conducted in preclinical and clinical studies have focused on soft and hard tissue changes following tooth extraction and immediate implant placement. Different approaches for hard and soft tissue grafting together with provisional restorations have been proposed to compensate tissue alterations. This review analyzed some relevant clinical and preclinical literature focusing on the impact of bone grafting procedures on immediate implant placement in terms of hard and soft tissue changes, aesthetic results, and patient-related outcomes.

Clinical protocol selection for alveolar ridge augmentation at sites exhibiting slight, moderate, and severe horizontal ridge deficiencies

FOCUSED CLINICAL QUESTION

What factors identify the optimal bone augmentation techniques for managing slight, moderate, and severe horizontal alveolar ridge deficiency (ARD) at dental implant sites?

SUMMARY

Horizontal ARD is a concern at a high proportion of sites receiving dental implants, and clinicians have developed a variety of surgical procedures to address such defects. In a particular case, selection of the optimal treatment may depend predominantly on defect severity, location (anterior versus posterior), and configuration (contained versus noncontained). This report provides a framework for selecting an augmentation method when presented with a slight, moderate, or severe horizontal ARD at a site requiring dental implant placement.

CONCLUSION

Multiple treatment options are available for planned implant sites exhibiting horizontal ARD; severe posterior and slight anterior defects intuitively call for different approaches. Although rigid guidelines for selecting the optimal augmentation method do not exist, some techniques are poorly suited for esthetically demanding sites. A framework considering defect severity, location, and configuration may help guide clinical decisions on this topic.

Clinical and cone beam computed tomography outcomes of maxillary anterior implant restorations after immediate implant placement with interim restorations: A 1- to 14-year retrospective analysis

STATEMENT OF PROBLEM: Achieving and maintaining optimal tissue health and esthetics when immediately placing maxillary anterior implants with interim restorations has been challenging and the clinical outcomes heterogenous.

PURPOSE

The purpose of this retrospective study was to evaluate the clinical outcomes of immediate placement of maxillary anterior implants with interim restorations and compare the tomographic and clinical results before and after implant placement in participants followed for 1 to 14 years.

MATERIAL AND METHODS

Twenty participants receiving 25 postextraction single implants in the anterior maxilla were studied. Clinical parameters included pink esthetic score (PES) and white esthetic score (WES), peri-implant phenotype, implant probing, plaque index, and cone beam computed tomography (CBCT) to compare initial and at least 1 year after crown placement (postoperative). For qualitative variables, a descriptive analysis was carried out. The PES and WES results were analyzed by using nonparametric statistics, the median (ME) and the interquartile range (IQR) were used as summary measures, and the Wilcoxon sum of signs test was used to compare the total scores between the intervention area and the contralateral tooth. To compare pre- and postoperative data points, the paired t test was used (α=.05).

RESULTS

Mean ±standard deviation (SD) time of follow-up was 7.6 ±4.2 years. Twenty participants with a mean ±SD age of 62.4 ±11.0 years old received 25 implants. Mean ±SD initial torque value at implant placement was 38.6 ±9.63 Ncm. Bone height at the top of the alveolar ridge (BH) and bone width at the middle of the alveolar ridge (BW2) showed a statistically significant decrease between the initial and subsequent CBCT measurements (both P<.001). Likewise, the bone width at the alveolar crest (BW1) showed a statistically significant decrease between the initial and post-CBCT measurements (P=.006). Facial bone integrity (FBI) revealed a statistically significant increase between the initial and postoperative time periods (P<.001). The PES index showed a median of 9.0 IQR (8-10), statistically lower than the contralateral tooth (P=.032). No significant differences were found for the WES index or for FBI, regardless of the peri-implant phenotype.

CONCLUSIONS

Immediate implant placement in the maxillary anterior sextant was found to be a predictable procedure with good esthetic results when the protocol described was used. Labial bone loss is inevitable after tooth extraction but can be compensated for by filling the space with a xenograft material. Long-term gingival tissue integrity was maintained, regardless of phenotype, in periodontally healthy participants.

Considering the Value of 3D Cultures for Enhancing the Understanding of Adhesion, Proliferation, and Osteogenesis on Titanium Dental Implants

BACKGROUND

Individuals with pathologic conditions and restorative deficiencies might benefit from a combinatorial approach encompassing stem cells and dental implants; however, due to the various surface textures and coatings, the influence of titanium dental implants on cells exhibits extensive, wide variations. Three-dimensional (3D) cultures of stem cells on whole dental implants are superior in testing implant properties and were used to examine their capabilities thoroughly.

MATERIALS AND METHODS

The surface micro-topography of five titanium dental implants manufactured by sandblasting with titanium, aluminum, corundum, or laser sintered and laser machined was compared in this study. After characterization, including particle size distribution and roughness, the adhesion, proliferation, and viability of adipose-derived stem cells (ADSCs) cultured on the whole-body implants were tested at three time points (one to seven days). Finally, the capacity of the implant to induce ADSCs' spontaneous osteoblastic differentiation was examined at the same time points, assessing the gene expression of collagen type 1 (coll-I), osteonectin (osn), alkaline phosphatase (alp), and osteocalcin (osc).

RESULTS

Laser-treated (Laser Mach and Laser Sint) implants exhibited the highest adhesion degree; however, limited proliferation was observed, except for Laser Sint implants, while viability differences were seen throughout the three time points, except for Ti Blast implants. Sandblasted surfaces (Al Blast, Cor Blast, and Ti Blast) outpaced the laser-treated ones, inducing higher amounts of coll-I, osn, and alp, but not osc. Among the sandblasted surfaces, Ti Blast showed moderate roughness and the highest superficial texture density, favoring the most significant spontaneous differentiation relative to all the other implant surfaces.

CONCLUSIONS

The results indicate that 3D cultures of stem cells on whole-body titanium dental implants is a practical and physiologically appropriate way to test the biological characteristics of the implants, revealing peculiar differences in ADSCs' adhesion, proliferation, and activity toward osteogenic commitment in the absence of specific osteoinductive cues. In addition, the 3D method would allow researchers to test various implant surfaces more thoroughly. Integrating with preconditioned stem cells would inspire a more substantial combinatorial approach to promote a quicker recovery for patients with restorative impairments.

Inter-implant distance and buccal bone thickness for a novel implant design: a preclinical study

OBJECTIVES

This study assessed bone height between novel tapered implants at different inter-implant thread peak (TP) distances, and the impact of TP distance from outer buccal bone (BB) on marginal bone levels (MBL).

MATERIALS AND METHODS

Fully tapered implants with 0.5-mm thread depth and TP diameter 1 mm wider than the shoulder diameter were placed in healed ridges of minipigs. On one side, four implants were placed with inter-implant TP distances of 1, 2, or 3 mm corresponding to inter-implant implant shoulder distances of 2, 3, and 4 mm respectively. Three implants were placed on the other side with TP distances to outer BB of > 1 mm, 0.5-1 mm, or < 0.5 mm. After 12 weeks, (a) first bone-to-implant contact (fBIC), total BIC, bone area-to-total area (BATA), and coronal bone height between implants (Bi ½ max) for inter-implant distance, and (b) fBIC, BIC, and perpendicular crest to implant shoulder (pCIS) for BB were evaluated.

RESULTS

No significant differences in bone healing and inter-implant bone height were noted for any of the TP distances. BB resorption was significant when TP distance to outer BB was < 0.5 mm. However, fBIC was lowest with TP to outer BB of 1.75 mm.

CONCLUSIONS

Inter-implant bone height between adjacent implants can be maintained even at an inter-implant TP distance as low as 1 mm. A minimum TP to outer BB distance of 0.75 mm is required for predictable maintenance of MBL.

CLINICAL RELEVANCE

Inter-implant distance and BB thickness are clinically relevant and require preclinical research to clarify concepts.

Anterior Maxillary Labial Bone Thickness on Cone Beam Computed Tomography

AIM

The objective of this research was to measure the labial bone thickness (LBT) in relation to the 6 anterior maxillary teeth at different levels along the long axis and the distance between cementoenamel junction and bone crest (CEJ-BC) based on cone beam computed tomography (CBCT) scans retrieved from patients of Arab ethnicity and identify any association with patients' characteristics.

MATERIALS AND METHODS

A total of 100 CBCT scans were evaluated by one calibrated examiner. The thickness of the labial bone was measured perpendicular to the long axis of the tooth at 1, 3, and 5 mm from the alveolar crest (LBT-1, LBT-3, and LBT-5, respectively) and CEJ-BC using a medical imaging viewer.

RESULTS

CBCT scans of 58 female patients and 42 male patients with a mean age of 39.7 ± 9.5 years were included. A high variation of CEJ-BC was observed (range, 0.55-3.90 mm). Statistically significant higher CEJ-BC values were associated with men and increased age (>50 years). The overall means of LBT-1 were 0.76 ± 0.26, 0.79 ± 0.26, and 0.83 ± 0.37 mm; LBT-3: 0.92 ± 0.36, 1.05 ± 0.46, and 1.03 ± 0.48 mm; LBT-5: 1.17 ± 0.52, 0.80 ± 0.45, and 0.81 ± 0.40 mm for central incisors, lateral incisors, and canines, respectively. The LBT was <1 mm in 74.2% of all maxillary anterior teeth, with central incisors showing the highest predilection (85% with LBT <1 mm). No significant association between LBT and patient characteristics was observed.

CONCLUSIONS

The CEJ-BC distance is greater in men and increases with age, particularly in those aged 50 years and older. The LBT in the 6 maxillary anterior teeth is predominantly thin (<1 mm) and has no correlation to age or sex. An increased LBT was observed at a 3-mm level when compared with LBT-1 and LBT-5. Such variability should be taken into consideration when planning for implant placement.

Factors Associated with Esthetic Outcomes of Flapless Immediate Placed and Loaded Implants in the Maxillary Incisor Region—Three-Year Results of a Prospective Case Series

Flapless immediate implant placement and provisionalization (FIIPP) is often associated with an increased risk of buccal soft-tissue recession. This study aims to assess the 3-year esthetic outcome. In 100 consecutive patients, one maxillary incisor, with or without a pre-extraction buccal bone defect (≤5 mm), was replaced by an implant installed in a maximal palatal position (buccal gap ≥2 mm). The created gaps were filled with bovine bone substitute. Patient satisfaction (PS), pink esthetic scores (PES/modPES), and white esthetic score (WES) were calculated at different time points. A multilevel regression analysis (MRA) was performed to analyze which factors may be associated with the esthetics. After three years, PS scored 8.9 ± 0.84 on a scale of 10 (n = 83), and the soft-tissue esthetics were high (PES = 12.2; modPES = 8.5), as was the WES (8.2), showing no decrease from one year. Buccal bone defect size and smoking could not be associated with the soft-tissue outcome; however, implant location, gap size, and emergence profiles could. Performing FIIPP, the final crown (WES) scored highest when it was cemented, the soft tissue (PES/modPES) in central-incisor positions, and all (WES/PES/modPES) with concave emergence profiles.

Classification of premolars sagittal root position and angulation for immediate implant placement: a cone beam computed tomography study

OBJECTIVES

Sagittal root position (SRP) and buccal plate thickness are important considerations in implant treatment planning. The objective of this study was to classify the relationship of the SRP and angulation to the osseous housing to assist treatment plan making for immediate implant placement in the premolar region.

STUDY DESIGN

We classified the SRP and angulations of the maxillary and mandibular premolars and measured the buccal plate thickness of 150 patients using cone beam computed tomography to support clinical decision making.

RESULTS

Regarding SRP types, 41.67%, 51.83%, 3.67%, and 2.83% of maxillary premolars and 84.33%, 15%, 0%, and 0.67% of mandibular premolars were classified as types B, M, L, and N, respectively. In terms of angulation, 20.83%, 46%, 32.17%, and 1% of maxillary premolars and 2%, 5.33%, 36.67%, and 56% of mandibular premolars were grouped into classes 1, 2, 3, and 4, respectively. The buccal bone thickness at most locations in premolar regions was <1 mm.

CONCLUSIONS

The classification of SRP and angulation will assist in treatment plan making for immediate implant placement in the premolar region.

Soft-Tissue Augmentation in Periodontally Compromised Patients during Immediate Placement and Immediate Loading Dental Implant Surgery - A Retrospective Study

Introduction

The purpose of this article is to describe a soft-tissue augmentation procedure for multiple tooth extraction sites during immediate placement and immediate loading (IPIL) dental implant surgery in periodontally compromised patients and to present follow-up results of its effectiveness.

Methods

A retrospective study was conducted on data from patients who underwent IPIL dental implant surgery between 2018 and 2021 at an oral implant centre in Bulgaria. Based on inclusion and exclusion criteria, 103 patients were included, 53 of whom had pre-operative indications for connective tissue grafts (CTGs) and 50 of whom did not. The post-operative incidence of gum recession was evaluated in the two patient groups.

Results

The majority of the 53 patients (56.60%) had six, seven or eight tooth sites grafted. A significant proportion (87%) needed CTGs at the canine teeth (13 and 23), P < 0.001. The post-operative data showed a low incidence of gum recessions in both the patient groups, with a lower rate in the CTG group at tooth no: 13 (2.20% vs. 18%, P = 0.016) and in the total sum of 10 tooth sites with CTGs (P = 0.001). A reduction in gum problems and increased satisfaction with gum health and aesthetics were reported by 100% of the CTG patients.

Discussion

Soft-tissue augmentation at multiple tooth extraction sites during IPIL dental implant treatment may benefit periodontally compromised patients through an improved prosthesis-tissue interface in the aesthetic area and a reduction in gum infections, swelling, bleeding and pain.

Assessing the Efficacy of Whole-Body Titanium Dental Implant Surface Modifications in Inducing Adhesion, Proliferation, and Osteogenesis in Human Adipose Tissue Stem Cells

BACKGROUND

Although the influence of titanium implants' micro-surface properties on titanium discs has been extensively investigated, the research has not taken into consideration their whole-body effect, which may be considered possible using a combinatorial approach.

METHODS

Five titanium dental implants with a similar moderate roughness and different surface textures were thoroughly characterized. The cell adhesion and proliferation were assessed after adipose-tissue-derived stem cells (ADSCs) were seeded on whole-body implants. The implants' inductive properties were assessed by evaluating the osteoblastic gene expression.

RESULTS

The surface micro-topography was analyzed, showing that hydroxyapatite (HA)-blasted and bland acid etching implants had the highest roughness and a lower number of surface particles. Cell adhesion was observed after 24 h on all the implants, with the highest score registered for the HA-blasted and bland acid etching implants. Cell proliferation was observed only on the laser-treated and double-acid-etched surfaces. The ADSCs expressed collagen type I, osteonectin, and alkaline phosphatase on all the implant surfaces, with high levels on the HA-treated surfaces, which also triggered osteocalcin expression on day seven.

CONCLUSIONS

The findings of this study show that the morphology and treatment of whole titanium dental implants, primarily HA-treated and bland acid etching implants, impact the adherence and activity of ADSCs in osteogenic differentiation in the absence of specific osteo-inductive signals.

Simultaneous presence of Mycoplasma salivarium and Tannerella forsythia in the implant sulcus after lateral augmentation with autogenous root grafts is associated with increased sulcus probing depth

Objective

To characterize a potential pathogenic role of Mycoplasma salivarium and bacterial co-detection patterns on different implant augmentation types.

Material and methods

36 patients were non-randomly assigned to autogenous lateral alveolar ridge augmentation with either cortical autogenous bone blocks, or healthy autogenous tooth roots or non-preservable teeth. Mucosal inflammation was assessed by probing pocket depth (PD) at all sampling sites and by bleeding on probing (BOP) in a subset of sampling sites, and standardized biofilm samples were obtained from the submucosal peri-implant sulcus and sulcus of a contralateral tooth at two times (t1 after implant placement; t2 after six months). Seven bacterial species were quantified using Taqman PCR.

Results

Mucosal inflammation did not differ between augmentation groups, but peri-implant sulci showed increased abundance of M. salivarium after augmentation with autogenous tooth roots lasting for at least six months (t1 p = 0.05, t2 p = 0.011). In M. salivarium-positive samples, Tannerella forsythia was correlated with PD (R = 0.25, p = 0.035) This correlation was not observed in M. salivarium-negative samples. Compared to all other samples, PD was deeper in co-detection (i.e., simultaneous M. salivarium and T. forsythia) positive samples (p = 0.022). No association of single or co-detection of bacteria with BOP was observed.

Conclusion

Presence of M. salivarium in peri-implant sulci varies with augmentation method and is associated with increased PD but not BOP. A potential causal role of M. salivarium in inflammation through a mechanism involving co-presence of T. forsythia requires further study.

Implant site development requirements in an advanced dental education program: A series of 290 implants

PURPOSE

Our purpose was to assess the frequency and impact of various site development procedures provided before, during, and after implant placement in an advanced dental education program.

METHODS

We evaluated all implant cases completed by two residents in each of three consecutive periodontics residency classes. Dependent variables included implant failure, complication occurrence, presence of radiographic bone loss, and need for tissue augmentation. We analyzed these outcomes against a panel of explanatory covariates.

RESULTS

Our study sample involved 370 site development procedures at 290 implant sites in 160 patients. Three factors exhibited statistically significant associations with need for tissue augmentation: alveolar ridge preservation (ARP) (odds ratio [OR] 0.28; 95% confidence interval [CI] 0.13, 0.57), immediate implant placement (IIP) (OR 0.21; 95% CI 0.10, 0.47), and implant submergence (OR 8.3; 95% CI 4.5, 15.3). Four factors predicted treatment complications: ARP (OR 6.1; 95% CI 1.3, 29.1), IIP (OR 6.1; 95% CI 1.06, 35.3), implant submergence (OR 5.3; 95% CI 1.1, 24.9), and mandibular arch (OR 31.3; 95% CI 1.9, 500). Anterior sites (OR 2.7; 95% CI 1.3, 5.8) were more likely to receive IIP.

CONCLUSIONS

In the evaluated sample, implant placement at a site exhibiting a favorable volume of native bone was rare. Seventy-eight percent of sites received hard tissue grafting during the treatment phase. The use of ARP or IIP at tooth extraction reduced subsequent tissue augmentation requirements. Education and training in ARP and other site development procedures may enhance the clinical practice and treatment outcomes of implant surgeons.

Does initial buccal crest thickness affect final buccal crest thickness after flapless immediate implant placement and provisionalization: A prospective cone beam computed tomogram cohort study

BACKGROUND

Flapless immediate implant placement and provisionalization (FIIPP) in the aesthetic zone is still controversial. Especially, an initial buccal crest thickness (BCT) of ≤1 mm is thought to be disruptive for the final buccal crest stability jeopardizing the aesthetic outcome.

PURPOSE

To radiographically assess the BCT and buccal crest height (BCH) after 1 year and to calculate the correlation between initial and final achieved BCT.

MATERIALS AND METHODS

The study was designed as a prospective study on FIIPP. Only patients were included in whom one maxillary incisor was considered as lost. In six centers, 100 consecutive patients received FIIPP. Implants were placed in a maximal palatal position of the socket, thereby creating a buccal space of at least 2 mm, which was subsequently filled with a bovine bone substitute. Files of preoperative (T0), peroperative (T1) and 1-year postoperative (T3) cone beam computed tomogram (CBCT) scans were imported into the Maxillim™ software to analyze the changes in BCT-BCH over time.

RESULTS

Preoperatively, 85% of the cases showed a BCT ≤1 mm, in 25% of the patients also a small buccal defect (≤5 mm) was present. Mean BCT at the level of the implant-shoulder increased from 0.6 mm at baseline to 3.3 mm immediate postoperatively and compacted to 2.4 mm after 1 year. Mean BCH improved from 0.7 to 3.1 mm peroperatively, and resorbed to 1.7 mm after 1 year. The Pearson correlation of 0.38 between initial and final BCT was significant (p = 0.01) and therefore is valued as moderate. If only patients (75%) with an intact alveolus were included in the analysis, still a "moderate correlation" of 0.32 (p = 0.01) was calculated.

CONCLUSIONS

A "moderate correlation" was shown for the hypothesis that "thinner preoperative BCT's deliver thinner BCT's" 1 year after performing FIIPP.

Buccal bone dimensional changes at immediate implant sites in the maxillary esthetic zone within a 4-12-month follow-up period: A systematic review and meta-analysis

OBJECTIVE

To evaluate the changes in buccal bone dimensions (CBD) following immediate implant placement in the maxillary esthetic zone and to identify the factors influencing the degree of buccal bone resorption for different placement and restoration protocols.

MATERIAL AND METHODS

An electronic search was conducted using the EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), and MEDLINE (PubMed) databases, combined with a manual and gray literature search, up to January 2021. Selected clinical studies had to report the changes in horizontal buccal bone dimension in maxillary immediate implantation sites (premolar to premolar) at baseline and at follow-up visits within a year of implantation. A meta-analysis was conducted to calculate the mean value of the changes in horizontal and vertical buccal bone dimensions (CHBD and CVBD) around implants. To further investigate the heterogeneity and identify factors associated with buccal bone loss after immediate implant placement, subgroup analysis and univariate meta-regression were performed.

RESULTS

From a total of 3498 articles, 4 randomized controlled trials and 12 nonrandomized controlled trials were included for analysis. The mean survival rate of 568 implants was 99.6%. The mean CHBD and CVBD values were 0.71 mm (95% confidence interval: [0.56, 0.86]) and 0.58 mm (95% confidence interval: [0.43, 0.72]), respectively. For possible factors that related to bone resorption, including buccal bone thickness, flap design, bone grafting, horizontal defect dimension, and restoration protocol, bone grafting was the only variable that significantly influenced CHBD.

CONCLUSIONS

This study demonstrated that immediate implant placement in the esthetic zone does not prevent buccal bone from resorption. Due to data heterogeneity and the small sample size of the studies included in the analysis, further well-conducted, randomized controlled trials with homogeneous samples are required to investigate the correlation of CBD with different variables.

Hard Tissue Volume Stability Effect beyond the Bony Envelope of a Three-Dimensional Preformed Titanium Mesh with Two Different Collagen Barrier Membranes on Peri-Implant Dehiscence Defects in the Anterior Maxilla: A Randomized Clinical Trial

This single-blinded, randomized, controlled study aimed to clinically and radiographically evaluate hard tissue volume stability beyond the bony envelope using three-dimensional preformed titanium mesh (3D-PFTM) for peri-implant dehiscence defects in the anterior maxilla. A total of 28 patients who wished to undergo implant surgery combined with guided bone regeneration (GBR) after extraction of a single maxillary anterior tooth were randomly assigned to two groups depending on the type of collagen membrane used, additionally with the 3D-PFTM—test (n = 14, cross-linked collagen membrane; CCM) and control (n = 14, non-cross-linked collagen membrane; NCCM) groups. Each implant was evaluated radiographically using CBCT at baseline, immediately after surgery, and at 6 months postoperatively. The relative position and distances from the bony envelope to the outlines of the augmented ridge were further determined immediately after GBR and 6 months after healing. At the platform level, the mean horizontal hard tissue gain (HG) at all the sites was 2.35 ± 0.68 mm at 6 months postoperatively. The mean HG rate was 84.25% ± 14.19% in the CCM group and 82.56% ± 13.04% in the NCCM group, but the difference was not significant between the groups. In all cases, HG was maintained beyond the bony envelope even after 6 months of GBR. This study suggests that 3D-PFTM should be considered a valuable option for GBR for peri-implant dehiscence defects in the anterior maxilla. In addition, 3D-PFTM may confer predictable hard tissue volume stability even after the healing period of hard tissue augmented outside the bony envelope by GBR.

Retrospective Analysis of the Effect of Three-Dimensional Preformed Titanium Mesh on Peri-Implant Non-Contained Horizontal Defects in 100 Consecutive Cases

This study aimed to clinically and radiographically evaluate the results of guided bone regeneration (GBR) using three-dimensional preformed titanium mesh (3-D-PFTM) for non-contained horizontal defects in 100 consecutive cases. This study involved 100 patients (129 implants) with peri-implant non-contained horizontal defects. The patients were divided into three groups: 3-D-PFTM alone (Group 1), 3-D-PFTM plus cross-linked collagen membrane (Group 2), and 3-D-PFTM plus non-cross-linked collagen membrane (Group 3). Each implant was evaluated radiographically using CBCT at baseline and 6 months postoperatively. At the platform level, the mean horizontal hard tissue gain of all the sites was 3.1 ± 1.3 mm at 6 months postoperatively. The mean rate of mesh exposure was 11.8% in Group 1, 4.2% in Group 2, and 5.0% in Group 3. The mean hard tissue gain rate was 71.0 ± 23.0% in group 1, 84.2 ± 21.5% in group 2, and 84.0 ± 22.9% in group 3. Groups 2 and 3 showed significantly higher hard tissue gain rates than group 1. However, there was no significant difference between the rates in groups 2 and 3. Within the limitations of this study, 3-D-PFTM should be considered as a valuable option for GBR for peri-implant non-contained horizontal defects. The use of an additional resorbable collagen membrane provides additional advantages.

The influence of initial defect morphology of alveolar ridge on volumetric change of grafted bone following guided bone regeneration in the anterior maxilla region: an exploratory retrospective study

Background

This study aimed to explore the influence of initial ridge defect morphology on the outcome of guided bone regeneration (GBR) in the anterior maxilla region.

Methods

Cone beam computed tomography (CBCT) examinations of patients who participated in a previous randomized controlled trial were used to assess linear and volumetric changes of bone grafts (LCB and VCB) from immediately (T0) to 6 months (T1) after surgery. The three-dimensional (3D) surface rendering of the initial defect was reconstructed, and morphological variables were defined in mesial-distal, buccal-lingual, and coronal-apical directions. The Spearman correlation, logistic regression model, and receiver operating characteristic (ROC) analyses were used to assess the possible association between initial defect morphological variables and VCB.

Results

A total of 62 eligible patients were included in this study. The median value of LCB was less than 20% at different levels, while the corresponding value of VCB was 52.0%. The Spearman correlation analysis showed that the standard deviation of buccal-lingual distance (BL_SD) was negatively associated with VCB (r=-0.315, P=0.013), whereas the ratio of maximum coronal-apical/mesial-distal distance (R_mCA/mMD) was positively related to VCB (r=0.607, P<0.001). The multivariate regression analysis revealed that the prognosis effect of BLSD (OR: 0.220, 95% CI: 0.074 to 0.655, P=0.0047) and R_mCA/mMD (OR: 7.045, 95% CI: 2.361 to 21.024, P=0.0017) remained significant. ROC curve analysis showed that R_mCA/mMD could be used to correctly classify VCB in 78.9% patients and BLSD in 71.0% of patients, as classified by the median of VCB. The discrimination value of BLSD and R_mCA/mMD revealed the areas under curve (AUC) of 0.71 (95% CI: 0.545 to 0.883) and 0.74 (95% CI: 0.573 to 0.913), respectively.

Conclusions

Within the limitations of this study, the present data confirmed the effect of initial ridge morphology on the GBR outcome in the anterior maxilla region. Specifically, a defect morphology with more BLSD and/or lower R_mCA/mMD may significantly decrease the resorption amount of grafted bone.

Impact of implant location on the prevalence of peri-implantitis: A systematic review and meta- analysis

OBJECTIVES

To evaluate scientific evidence about the impact of implant location on the prevalence of peri-implantitis at implant level.

SOURCE

Databases (PubMed, Embase and Cochrane) were searched until March 2020without limitations on language or publication year. Hand searches and gray literature were also included.

STUDY SELECTION

Clinical studies reporting data on prevalence of peri-implantitis in anterior and posterior regions at implant level, and evaluations of implants with at least 1 year of function were selected.

DATA

Ten studies with a low risk of bias were included. Meta-analysis was performed to estimate the pooled risk ratio. A significantly higher prevalence of peri-implantitis in anterior region compared to posterior region was found (Risk ratio: 1.34; 95 % CI: [1.07, 1.69]; p = 0.01). Meta-regression was performed to analyze the potential influence of confounding factors by calculating p-value of the coefficient. Subjects (p = 0.827), implants (p = 0.859) and age (p = 0.656) did not significantly influence the outcome. Subgroup analysis by jaw revealed significantly higher prevalence of peri-implantitis in maxillary anterior (Risk ratio: 1.37; 95 % CI: [1.10, 1.71]; p = 0.005) and mandibular anterior (Risk ratio: 1.76; 95 % CI: [1.29, 2.42]; p = 0.0004) regions compared to maxillary posterior region. No significant difference was found between maxillary anterior and mandibular posterior (Risk ratio: 1.15; 95 % CI: [0.75, 1.75]; p = 0.53) regions. A meta-analysis was precluded between mandibular anterior and mandibular posterior regions due to high statistical heterogeneity (I ² = 76 %).

CONCLUSIONS

Implants in the maxillary anterior and mandibular anterior regions had a higher prevalence of peri-implantitis compared to the maxillary posterior region.

CLINICAL SIGNIFICANCE

Practitioners should strictly grasp the indications for patients missing anterior teeth and make comprehensive treatment planning.

Computer-aided three-dimensional assessment of periodontal healing distal to the mandibular second molar after coronectomy of the mandibular third molar: a prospective study

Background

The periodontal healing distal to the mandibular second molar (M2M) after coronectomy of the M3M has shown controversial results. We aimed to combine a digital method with cone-beam computed tomography (CBCT) and estimate periodontal healing of M2M after M3M coronectomy. An accurate and stable indicator in three dimensions was also explored tentatively.

Methods

Patients with a M3M in contact with the inferior alveolar canal were included. CBCT was applied immediately after coronectomy (baseline) and 6-months later. Data were investigated with digital software for registration. Previously reported and coronectomy-related factors were included for univariate and multivariate analyses.

Results

A total of 181 patients (213 M3Ms) completed 6-month follow-up. Significant reduction in the distal intra-bony defect (DBD) depth of the M2M was shown (1.28 ± 1.24 mm, P < 0.001). DBD depth of the M2M at baseline was the most influential factor (r = 0.59), followed by preoperative M3M condition, age, rotation and migration of the root complex. Remaining enamel (OR = 6.93) and small retromolar space (0.67) contributed to re-contact of the root complex and M2M. Bone volume regenerated in the distal 2 mm was associated significantly with DBD-depth reduction (r = 0.74, P < 0.001).

Conclusions

Bone volume regenerated in the distal 2 mm of the M2M denoted stability of distal periodontal healing of the M2M. DBD depth at baseline was the most influential factor for healing of a DBD of the M2M after M3M coronectomy. The remaining enamel and a small retromolar space could contribute to re-contact of the root complex and the M2M.

Trial registration

China Clinical Trial Center, ChiCTR1800014862. Registered 10 February 2018,

Immediate implant placement and provisionalization: Aesthetic outcome 1 year after implant placement. A prospective clinical multicenter study

BACKGROUND

Prospective aesthetic outcomes on a high number of patients after immediate implant placement and provisionalization (IIPP) are lacking.

PURPOSE

To analyze the aesthetic outcome after IIPP.

MATERIALS AND METHODS

One hundred consecutive patients with a failing maxillary incisor were provided with an immediately placed and provisionalized nonloaded implant using a flapless procedure and palatal implant positioning. The remaining gap buccally was filled with a bone substitute. Preoperatively (T0), 2 weeks postoperatively (T1), direct after placement of the permanent crown (T2), and 1 year after IIPP (T3), standardized light photographs were made. Change in aesthetic score was the primary outcome measure. Both the white aesthetic score (WES) and pink aesthetic score (PES) were used.

RESULTS

In the first year postsurgery, the mean total-WES and total-PES scores raised from 4.5 to 8.2, and from 9.9 to 12.1, respectively. The mean PES scores for mesial and distal papilla, soft tissue marginal level, contour, color, and texture, raised significantly (P < .05), while the alveolar process contour, on average, remained stable from T0 to T3.

CONCLUSIONS

Within the limitations of this 1-year research, it may be concluded that, following this minimal invasive IIPP procedure, a high aesthetic outcome was achieved.

The dimension and morphology of alveolar bone at maxillary anterior teeth in periodontitis: a retrospective analysis-using CBCT

The morphology of the alveolar bone at the maxillary anterior teeth in periodontitis patients was evaluated by cone-beam computed tomography (CBCT) to investigate the distribution of alveolar defects and provide guidance for clinical practice. Ninety periodontitis patients and 30 periodontally healthy individuals were selected to determine the morphology of the alveolar bone at the maxillary anterior teeth according to the degree of bone loss, tooth type, sex and age. The differences in the dimensions between periodontitis patients and healthy individuals were compared, and the distribution of alveolar bone defects was analyzed. A classification system was established regarding the sagittal positions and angulations of the teeth. The buccal residual bone was thicker and the lingual bone was thinner in the periodontitis patients than in the periodontally healthy individuals, and there were differences between the different tooth types, sexes and age subgroups. The buccal undercut was close to the alveolar ridge, while fenestration was reduced and the apical bone height was higher in periodontitis patients than in periodontally healthy individuals. The apical bone height increased with the aggravation of bone loss and age. The proportions of different sagittal positions changed with the aggravation of bone loss. Moreover, the teeth moved more buccally regarding the positions of the maxillary anterior teeth. The morphology of the alveolar bone at the maxillary anterior teeth differed between periodontitis patients and healthy individuals, and the differences were related to the degree of bone loss, tooth type, sex and age.

Preservation of Bone and Soft Tissue Components of the Alveolar Ridge during Immediate Implantation in the Aesthetic Zone of Jaws with Bone Deficiency

The use of immediate implantation (directly into the extracted tooth socket) in the aesthetic zone is a rather difficult task due to the specific structural features of the bone tissue of the alveolar processes and parts of the jaw. The aim of the study was to develop and evaluate the efficacy of the new method of immediate implantation during restoration of teeth in the anterior part of the jaw with bone deficiency, which allows obtaining a high aesthetic result.

Materials and Methods

The clinical study involved patients with partially edentulous anterior maxillae, chronic apical periodontitis and dental root fractures in the absence of possibility to restore these teeth with orthopedic structures. To identify the main criteria determining smile aesthetics, the detailed analysis of changes in the bone and soft tissues of the alveolar processes was made based on tooth extraction causes and dates. These criteria included gum biotype, the height of the distal and mesial interdental papillae; the width of the keratinized attached gingival area, gingival zeniths, the alveolar ridge thickness. The condition of the facial alveolar bone wall in the planned intervention area was assessed and its thickness was measured using cone-beam CT scan of the jaw. These parameters were measured during traditional immediate implantation, immediate implantation with a free connective tissue graft, implantation performed using the method developed by the authors and during delayed implantation in the anterior part. In each patient, the obtained data were compared with the results in the respective teeth area on the opposite side before the surgery, 4, 6 months and 1 year after the surgery.

Results

Clinical and X-ray studies of the developed method of immediate implantation in the aesthetic zone of the jaw with bone deficiency in the facial alveolar bone wall have convincingly demonstrated its efficacy in the long term (1 year after the surgery). The proposed protocol has made it possible to reduce the length of rehabilitation time, and most importantly, to stabilize and preserve the alveolar ridge architecture.

Conclusion

The proposed method showed the promising outlook for dental implant-supported restoration in difficult anatomical conditions.

Frequency of adequate mesiodistal space and faciolingual alveolar width for implant placement at anterior tooth positions

BACKGROUND

Prior studies have defined minimum mesiodistal space (MS) and faciolingual alveolar width (FAW) requirements for dental implant sites, and failure to observe these constraints may adversely impact peri-implant health and esthetics. However, to the authors' knowledge, no previous reports have established frequencies at which anterior tooth positions present favorable MS and FAW for implant accommodation.

METHODS

A single examiner analyzed 205 cone-beam computed tomographic images, recording MS and FAW available for implant placement at anterior tooth positions. The examiner compared measurements with standardized implant diameters to assess anticipated implant-to-tooth distances and peri-implant bone thicknesses.

RESULTS

In the esthetic zone, lateral incisor sites most frequently failed to present favorable MS. At maxillary lateral incisor positions, 22% (left) and 27% (right) of sites offered less than 2 millimeters between the proposed implant platform and the adjacent teeth. In mandibular incisor positions, implant-to-tooth distance was less than 2 mm at 79% through 97% of sites and less than 1.5 mm at 35% through 76% of sites. Over one-half of maxillary incisor sites and 78% through 95% of mandibular incisor sites exhibited FAW of less than 4 mm beyond implant diameter.

CONCLUSIONS

In the population evaluated, mandibular incisor positions frequently presented unfavorable MS to accommodate conventional narrow-diameter implants. In addition, considerable proportions of mandibular incisor and maxillary lateral incisor sites may be at risk of developing unfavorable peri-implant bone thickness when conventional narrow-diameter implants are used.

PRACTICAL IMPLICATIONS

Practitioners should consider small-diameter implants and nonimplant tooth replacement methods for many patients missing single mandibular incisors or maxillary lateral incisors.

What is the Optimum for Alveolar Ridge Preservation?

In the dental implant era, there has been growing interest in exploring the most effective methods to minimize morphologic alteration in the postextraction site. Despite modern methods of ridge preservation, resorption of the ridge is inevitable. The optimal approach to minimizing the rate and amount of these changes is still a subject of controversy. This article provides a contemporary review of the different approaches to preserve alveolar ridge dimensions. A suggested classification for single extraction sockets is presented along with multiple treatment options for each class.

Changes in alveolar process dimensions following extraction of molars with advanced periodontal disease: A clinical pilot study

OBJECTIVE

To use cone beam computed tomography (CBCT) to assess the alterations of socket dimensions after a 6-month healing period following molar extraction.

MATERIALS AND METHODS

Seventeen molars were extracted due to advanced periodontitis. CBCT scans were taken immediately after extraction and once more 6 months later. Superimposition of CBCT images was used to measure the following: horizontal changes at extraction sites at three corono-apical levels (-1, -3, and -5 mm) below the bone crest, three mesio-distal levels (mesial, central, and distal), vertical changes at nine regions of the alveolar crest, and alveolar bone volume.

RESULTS

The width of the central crests at -1 mm decreased by 0.59 and 0.72 mm in the buccal and 0.27 and 0.02 mm in the lingual, in the maxilla and mandible, respectively. No statistically significant decreases in the ridge height were observed except in the disto-palatal region with a 1.11 mm decrease in the maxilla (p < 0.05). Heights of the buccal and lingual bone plates decreased significantly and ranged from 0.56 to 1.38 mm in the mandible after 6 months of healing (p < 0.05). Overall, ridge height changes were not significantly different between the maxilla and mandible (p > 0.05) and no significant volumetric bone loss occurred in either maxillary or mandibular sockets after 6 months of healing.

CONCLUSIONS

Socket dimensions of molars with advanced periodontal disease showed a significant increase at the middle-central portion, although there were no significant changes of horizontal width 6 months following the procedures.

Buccal bone thickness at dental implants in the maxillary anterior region with large bony defects at time of immediate implant placement: A 1-year cohort study

Background

There is lack of studies regarding preservation and possible changes in BBT at dental implants.

Purpose

To assess, on cone beam computer tomograms, the presence of bone at the time of tooth extraction in the maxillary esthetic region and the mean buccal bone thickness 1 month and 1 year after final restoration placement in patients with large bony defects.

Material and Methods

In a cohort study, patients were selected presenting a failing tooth with a large bony defect (test group [n = 20]: large bony defect, immediate placed implant and delayed provisionalization). Results were compared with a group in which patients presented a failing tooth without or with a small bony defect: (control group [n = 20]: without or small bony defect, immediate placed implant and delayed provisionalization). Cone beam computer tomograms were made preoperatively, and 1 month and 1 year after placement of the restoration, and buccal bone thickness was analyzed.

Results

In both groups approximately 1 mm of buccal bone thickness was present after 1 month and 1 year, without a significant difference between the groups.

Conclusion

In patients with large bony defects at a failing tooth it was possible to create a bone layer buccally of the implant and this bone layer remained stable during a 1‐year follow‐up; there were no significant differences between thickness of buccal bone at 1 month and 1 year in patients with large buccal bony defects and patients without or with small bony defects.

Clinical relevance of dimensional bone and soft tissue alterations post-extraction in esthetic sites

The key to achieving pleasing esthetics in implant dentistry is a thorough understanding of the biological processes driving dimensional bone and soft tissue alterations post-extraction. The aim of the present report is first to characterize the extent of bone and soft tissue changes post-extraction and second to identify potential factors influencing tissue preservation in order to facilitate successful treatment outcomes. The facial bone wall thickness has been identified as the most critical factor influencing bone resorption and can be used as a prognostic tool in order to identify sites at risk for future facial bone loss subsequent to tooth extraction. Clinical studies indicated that thin bone wall phenotypes exhibiting a facial bone wall thickness of 1 mm or less revealed progressive bone resorption with a vertical loss of 7.5 mm, whereas thick bone wall phenotypes showed only minor bone resorption with a vertical loss of 1.1 mm. This is in contrast to the dimensional soft tissue alterations. Thin bone wall phenotypes revealed a spontaneous soft tissue thickening after flapless extraction by a factor of seven, whereas thick bone wall phenotypes showed no significant changes in the soft tissue dimensions after 8 weeks of healing. In sites exhibiting a limited bone resorption rate, immediate implant placement may be considered. If such ideal conditions are not present, other timing protocols are recommended to achieve predictable and pleasing esthetics. Socket preservation techniques for ridge preservation utilizing different biomaterials and/or barrier membranes often result in a better maintenance of tissue volumes, although the inevitable biological process of post-extraction bone resorption and bone modeling cannot be arrested. In summary, the knowledge of the biological events driving dimensional tissue alterations post-extraction should be integrated into the comprehensive treatment plan in order to limit tissue loss and to maximize esthetic outcomes.

Assessment of Bone Dimensions in the Anterior Maxilla: A Cone Beam Computed Tomography Study

PURPOSE

To evaluate labial and palatal bone thickness at the maxillary anterior teeth as well as distance from cemento-enamel junction (CEJ) to bone crest using cone beam computed tomography (CBCT).

MATERIALS AND METHODS

Measurements were obtained for maxillary anterior teeth of 120 subject CBCT volumes including thickness of labial and palatal plates of bone (coronal, middle, and apical thirds), and distance between CEJ and alveolar bone crest mid-labially, mesially, and distally.

RESULTS

The mean value of bone thickness at coronal, middle, and apical thirds of the labial side for central incisor roots were respectively: 0.73, 0.69, 0.60 (mm), for lateral incisors: 0.70, 0.61, 0.49 (mm), and for canines: 0.74, 0.53, 040 (mm). The thickness of palatal bone was significantly larger. The mean distance between CEJ and mid-labial bone crest for all sites was 2.16 mm.

CONCLUSION

Labial bone thickness is thin in the vast majority of maxillary anterior teeth. Use of CBCT facilitates planning for immediate implant placement and is helpful in the decision-making process when further bone augmentation is needed.

Craniofacial height in relation to cross-sectional maxillary and mandibular morphology

BACKGROUND

In order to gain a better understanding of how growth of the alveolar bone is linked to the vertical development of the face, the purpose of this study was to investigate if there is an association between the cross-sectional morphology of the maxillary and mandibular bodies with the craniofacial height, using images from cone beam computed tomography (CBCT).

METHODS

From 450 pre-treatment CBCT scans, 180 were selected to be included in the study. Lateral head images were generated from the CBCT scans and were used to categorise subjects into three groups based on their vertical craniofacial height. Cross-sectional images from CBCT volumes were reformatted of the maxillary and mandibular bodies at five locations in the maxilla and five in the mandible. Each image was measured at one height and two width measurements. Statistical analysis performed was the one-way analysis of variance with a Tukey post hoc test. A significance level of 5% was used in all comparisons.

RESULTS

Patients with large vertical craniofacial height had a significantly higher cross-sectional area both in the maxilla and in the mandible. In the same group, the cross-sectional area was significantly thinner in the mandible compared with the other two groups, especially in the anterior region.

CONCLUSIONS

This study further highlights the close relationship between craniofacial height and alveolar bone dimensions and contributes with important knowledge for planning and follow-up of comprehensive dental- and orthodontic treatments.

Immediate implant placement: the fate of the buccal crest. A retrospective cone beam computed tomography study

This retrospective study aimed to analyse the fate of the buccal crest after immediate implant placement (IIP) through the use of cone beam computed tomography (CBCT). In 16 consecutive patients, an implant was placed in a more palatal position after extraction, thereby creating a gap of at least 2mm between the implant and the buccal crest. Subsequently, this gap was filled with a bone substitute. Preoperatively, immediate postoperatively, and late postoperatively, a CBCT was made to measure the thickness of the buccal crest. After application of the bone substitute, the buccal crest increased in thickness from 0.9mm to 2.4mm (mean). At a mean of 103 weeks after IIP, late postoperative CBCT scans showed that the thickness of the buccal crest was compacted to 1.8mm. In the same period, the height of the buccal crest increased by 1.6mm (mean) to, on average, 1.2mm above the implant shoulder. The aesthetic outcome was analysed using the White and Pink Esthetic Score (WES and PES). Both scored high: 8.4 and 11.8, respectively. Within the limitations of this study, the results of this IIP protocol are promising. Long-term prospective research on this topic on a large number of patients is necessary.

Classification of the Root Position of the Maxillary Central Incisors and its Clinical Significance in Immediate Implant Placement

PURPOSE

The aim was to classify the relationship of the sagittal root positions of the maxillary central incisor to alveolar bone using cone beam computed tomography (CBCT).

METHODS

CBCT images of 934 maxillary central incisors were retrospectively reviewed included 542 men and 392 women. The sagittal root position in the alveolar bone was classified as buccal, middle, or palatal. The sagittal buccal type was further classified into 3 subtypes: I, II, and III.

RESULTS

The root position type was buccal in 95.4% of the 934 incisors, middle in 4.4%, and palatal in 0.2%. In the buccal type, 47.5%, 44.2%, and 8.3% were subtypes I, II, and III, respectively. There was no significant difference in the major and subtypes of root position between the male and female subjects (both P > 0.05).

CONCLUSIONS

In Chinese adults, the predominant type of sagittal root position of the maxillary central incisor is buccal. This classification system is useful in planning the implant site for immediate placement in the maxillary esthetic zone.

Buccal bone thickness at dental implants in the aesthetic zone: A 1-year follow-up cone beam computed tomography study

Sufficient buccal bone thickness (BBT) is important for an optimal aesthetic outcome of implant treatment in the aesthetic zone. The aim of the study was to assess BBT at dental implants placed in the aesthetic zone (incisor, canine or first premolar in the maxilla) (immediate or delayed, with or without immediate provisionalization) with cone beam computed tomography (CBCT) as a function of time. Eighty patients were divided into 4 groups according to size of the buccal bony defect (<5 or ≥5 mm) after removal of the tooth, and timing of implant placement and provisionalization. CBCTs were made 1 month and 1 year after placement of the implant crown. BBT varied from 0.79 mm to 2.12 mm at 1 month and from 0.71 mm to 2.04 mm at 1 year. Change of BBT between 1 month and 1 year was negligible. This study concluded that BBT at dental implants in the aesthetic zone appears to be stable for immediate and delayed placed implants after placement of the definitive crown, independent of the size of buccal bone defect prior to implant insertion and timing of provisionalization.

Benefits of mineralized bone cortical allograft for immediate implant placement in extraction sites: an in vivo study in dogs

Purpose

The aim of the present study was to evaluate the effectiveness of using a mineralized bone cortical allograft (MBCA), with or without a resorbable collagenous membrane derived from bovine pericardium, on alveolar bone remodeling after immediate implant placement in a dog model.

Methods

Six mongrel dogs were included. The test and control sites were randomly selected. Four biradicular premolars were extracted from the mandible. In control sites, implants without an allograft or membrane were placed immediately in the fresh extraction sockets. In the test sites, an MBCA was placed to fill the gap between the bone socket wall and implant, with or without a resorbable collagenous membrane. Specimens were collected after 1 and 3 months. The amount of residual particles and new bone quality were evaluated by histomorphometry.

Results

Few residual graft particles were observed to be closely embedded in the new bone without any contact with the implant surface. The allograft combined with a resorbable collagen membrane limited the resorption of the buccal wall in height and width. The histological quality of the new bone was equivalent to that of the original bone. The MBCA improved the quality of new bone formation, with few residual particles observed at 3 months.

Conclusions

The preliminary results of this animal study indicate a real benefit in obtaining new bone as well as in enhancing osseointegration due to the high resorbability of cortical allograft particles, in comparison to the results of xenografts or other biomaterials (mineralized or demineralized cancellous allografts) that have been presented in the literature. Furthermore, the use of an MBCA combined with a collagen membrane in extraction and immediate implant placement limited the extent of post-extraction resorption.

Critical buccal bone dimensions along implants

The buccal bone plate is a component of the alveolar process tightly related to the tooth it supports. A plethora of physiological and pathological events can induce its remodeling. Understanding this remodeling process and its extent is of major importance for the practitioner as it can affect the functional and esthetic outcome of implant surgery at the involved sites. Bone remodeling and resorption of the buccal bone plate are inevitable after tooth loss or extraction. To limit resorption, several ridge-preservation techniques of varying efficacy have been described. Bone resorption is equally found to occur upon implant placement and is thought to be a result of the surgical trauma inflicted as well as an adaptation process of the tissues to the new foreign body. Because of the implications of bone resorption on the soft-tissue levels and the general esthetic outcome, it is of primary importance for the practitioner to be able to evaluate the hard tissues and the inherent resorption risks in an effort to optimize the treatment strategies. Based on limited short-term data, the present general opinion advises the need for a 2-mm-thick buccal bone plate in order to avoid vertical bone resorption.

Assessment of buccal bone thickness of aesthetic maxillary region: a cone-beam computed tomography study

Purpose

The aim of this study was to analyze the anatomical dimensions of the buccal bone walls of the aesthetic maxillary region for immediate implant placement, based upon cone-beam computed tomography (CBCT) scans in a sample of adult patients.

Methods

Two calibrated examiners analyzed a sample of 50 CBCT scans, performing morphometric analyses of both incisors and canines on the left and right sides. Subsequently, in the sagittal view, a line was traced through the major axis of the selected tooth. Then, a second line (E) was traced from the buccal to the palatal wall at the level of the observed bone ridges. The heights of the buccal and palatal bone ridges were determined at the major axis of the tooth. The buccal bone thickness was measured across five lines. The first was at the level of line E. The second was at the most apical point of the tooth, and the other three lines were equidistant between the apical and the cervical lines, and parallel to them. Statistical analysis was performed with a significance level of P≤0.05 for the bone thickness means and standard deviations per tooth and patient for the five lines at varying depths.

Results

The means of the buccal wall thicknesses in the central incisors, lateral incisors and canines were 1.14±0.65 mm, 0.95±0.67 mm and 1.15±0.68 mm, respectively. Additionally, only on the left side were significant differences in some measurements of buccal bone thickness observed according to age and gender. However, age and gender did not show significant differences in heights between the palatal and buccal plates. In a few cases, the buccal wall had a greater height than the palatal wall.

Conclusions

Less than 10% of sites showed more than a 2-mm thickness of the buccal bone wall, with the exception of the central incisor region, wherein 14.4% of cases were ≥2 mm.

Influence of periodontal tissue thickness on buccal plate remodelling on immediate implants with xenograft

AIM

To evaluate the influence of gingival thickness and bone grafting on buccal bone plate remodelling after immediate implant placement in sockets with thin buccal bone, using a flapless approach.

MATERIALS AND METHODS

The gingiva of eight dogs was thinned at one side of the mandible, mandibular premolars were extracted without flaps, and four implants were installed on each side at 1.5 mm from the buccal bone. The sites were randomly assigned into: TG (test group) = thin gingiva; TG + GM (TG with grafting material); CG (control group) = normal gingiva; and CG + GM (CG with grafting material). After 12 weeks the dogs were sacrificed and the samples were processed for histological analysis.

RESULTS

All animals exhibited a thin buccal bone initially. In all the experimental groups the buccal gap was filled with newly formed bone and the buccal bone level was slightly apical to the implant shoulder. There were no statistically significant differences among the groups for the histomorphometric parameters.

CONCLUSIONS

The thickness of the buccal bone was a fundamental factor in buccal bone plate resorption, even with flapless implantation. The gingival thickness or the addition of a biomaterial in the gap did not influence the results.