Remodelling of interdental alveolar bone after periodontal flap procedures assessed by means of computer-assisted densitometric image analysis (CADIA)

Intraoral ultrasonography image registration for evaluation of partial edentulous ridge: A methodology and validation study

OBJECTIVES

Ultrasound (US) reveals details for diagnosing soft- and hard-tissue dimensions around teeth, implants, and the edentulous ridge, not seen in 2D radiographs. Co-registering free-hand US scans with other 3D modalities presents reliability challenges. This study first aims to develop and validate a registration method to longitudinally reproduce US images of the jawbone on a simulator. In addition, it also evaluates the degree of the anatomical match in humans between US images acquired by the proposed registration method and the commonly used freehand acquisitions in comparison to cone beam computed tomography (CBCT) and intra-oral optical scan (IOS), used as references.

METHODS

A previously introduced ultrasound phantom was employed as a CBCT-US hybrid, suitable for training and technique development of US guides in edentulous ridges. After establishing feasibility in the phantom, the methodology was validated in a cohort of 24 human subjects (26 cases). Soft tissues were delineated on US and IOS, and hard tissues on US and CBCT. US accuracy and repeatability from both guided and freehand scans (non-guided) was assessed as the average distance between US and the references.

RESULTS

Guided US images resembled the references more closely than freehand (non-guided) scans. Notably, delineation of soft and hard tissues was significantly more accurate when employing guides. In the phantom, guided scans exhibited an absolute mean deviation of 81.8 µm for gingiva and 90.4 µm for bone, whereas non-guided scans showed deviations of 150.4 µm and 177.2 µm, respectively. Similarly, in vivo, guided US outperformed non-guided US, with gingiva deviations of 125 µm and 196 µm, and bone deviations of 354 µm and 554 µm, respectively.

CONCLUSIONS

By using a registration method, guided US scans improved repeatability and accuracy of mapping hard and soft tissue of the edentulous ridge when compared to non-guided scans.

CLINICAL RELEVANCE

This guided US imaging method could lay the foundation for longitudinal evaluation of tissue behavior and dimensional changes with improved accuracy.

A clinical investigation to assess the regenerative potential of Biostite® (hydroxyapatite, type-I collagen and chondroitin-sulphate) with or without Paroguide® type-I collagen and chondroitin sulphate) membrane in the treatment of periodontal intrabony defects appraised with surgical re-entry and computer-assisted densitometric image analysis

Background

The traditional treatment procedures which aimed at treating periodontal disease did not result in true periodontal regeneration. Unpredictability about osseous defect fill after periodontal flap surgery has stemmed in the research of a variety of regenerative materials. This randomized clinical trial was conducted to compare regenerative potential of Biostite® bone graft material with and without Paroguide® a bioresorbable membrane in the treatment of periodontal osseous defects.

Materials and Methods

Twenty sites from a total of from ten patients were chosen for the study. Those sites were divided into experimental site A (Biostite®) and experimental site B (Biostite® with Paroguide®) at random. Plaque index and gingival index (GI) were the clinical parameters noted at baseline, 3rd, 6th and 9th months, whereas the probing pocket depth, clinical attachment level and gingival recession were noted at baseline, 6th and 9th months. Radiographic evaluation was made by using computer-assisted densitometric analysis. Intrasurgical measurements were done at baseline and 9 months. Statistical analysis was done using paired t-test and un-paired t-test.

Results

Both experimental site A and B showed a significant reduction in plaque and GI. All clinical parameters as well as radiographic image analysis showed highly significant improvement from baseline to 9 months for both sites. Inter-group comparison does not show statistically significant improvement.

Conclusion

The results of this study suggested that both Biostite® bone graft and Paroguide® membrane have promised encouraging results in the management of periodontal intrabony defects, however, the groups did differed to each other statistically.

A split-mouth randomized controlled trial to compare the rate of canine retraction after a soft tissue procedure compared against a corticotomy procedure for accelerated tooth movement

Background and Aim

Various methods to accelerate the orthodontic tooth movement have been used, among which corticotomy is considered to be the most common one. The suggested reasoning for such acceleration was the regional acceleratory phenomenon (RAP). Since the RAP is a property of both the hard and soft tissues, we designed a soft tissue flap procedure to compare the effects with the conventional corticotomy procedure. A split-mouth study was conducted where the two procedures were assessed in a single participant.

Patients and Methods

The total sample size was calculated to be 40 with 20 participants in each group. The rate of tooth movement was the primary outcome measure, and the secondary outcomes were dentoalveolar changes, which were studied in both the conventional corticotomy and the flap-only procedure based on a cone-beam computed tomography (CBCT) wherein the alveolar bone density (BD) around canines, tipping, and rotational changes in canines, premolars, and molars were assessed.

Results

Corticotomy resulted in greater canine angulation, lesser canine rotation and premolar rotation, and greater molar rotation compared with flap elevation, but these differences were statistically insignificant.

Conclusion

Though the corticotomy resulted in higher BD, the differences were statistically insignificant. There was no significant difference in the rate of space closure assessed by the two techniques compared.

Three-dimensional volumetric assessment of hard tissue alterations following horizontal guided bone regeneration using a split-thickness flap design: A case series

OBJECTIVES

To analyze morphological, volumetric, and linear hard tissue changes following horizontal ridge augmentation using a three-dimensional radiographic method.

METHODS

As part of a larger ongoing prospective study, 10 lower lateral surgical sites were selected for evaluation. Horizontal ridge deficiencies were treated with guided bone regeneration (GBR) using a split-thickness flap design and a resorbable collagen barrier membrane. Following the segmentation of baseline and 6-month follow-up cone-beam computed tomography scans, volumetric, linear, and morphological hard tissue changes and the efficacy of the augmentation were assessed (expressed by the volume-to-surface ratio).

RESULTS

Volumetric hard tissue gain averaged 605.32 ± 380.68 mm³. An average of 238.48 ± 127.82 mm³ hard tissue loss was also detected at the lingual aspect of the surgical area. Horizontal hard tissue gain averaged 3.00 ± 1.45 mm. Midcrestal vertical hard tissue loss averaged 1.18 ± 0.81 mm. The volume-to-surface ratio averaged 1.19 ± 0.52 mm³/mm². The three-dimensional analysis showed slight lingual or crestal hard tissue resorption in all cases. In certain instances, the greatest extent of hard tissue gain was observed 2-3 mm apical to the initial level of the marginal crest.

CONCLUSIONS

With the applied method, previously unreported aspects of hard tissue changes following horizontal GBR could be examined. Midcrestal bone resorption was demonstrated, most likely caused by increased osteoclast activity following the elevation of the periosteum. The volume-to-surface ratio expressed the efficacy of the procedure independent of the size of the surgical area.

Crown Lengthening Techniques and Modifications to Treat Excessive Gingival Display

Dental aesthetics are a fundamental treatment goal in dentistry, in which even minute deviations from the ideal may necessitate corrective treatment or constitute a suboptimal clinical outcome. A well-defined protocol that adheres to sound biological and surgical principles is necessary to harmoniously integrate the dental and periodontal components. This article reviews clinical and aesthetic guidelines based on these principles for clinical crown lengthening.

Impact of the periodontal phenotype in premolar and molar sites on bone loss following full thickness mucoperiosteal flap. A 1-year prospective clinical trial

BACKGROUND

Full thickness mucoperiosteal flap (FTF) elevation could potentially affect the periodontium of the involved teeth; it is not clear if the periodontal phenotype of teeth involved in a FTF may influence these changes. The aim of this study was to evaluate the impact of FTF on teeth periodontium, as well as assessing the impact of periodontal phenotype on bone remodeling.

METHODS

In this single arm prospective clinical trial, 26 subjects and a total of 52 adjacent teeth were included. Patients receiving implant surgery in the posterior area, at the time of implant site preparation, an FTF was extended one tooth mesial and distal to the planned site, and the flap was elevated both facially and lingually. Vertical and horizontal bone linear changes were measured on both adjacent teeth, using superimposed cone-beam computerized tomography (CBCT) images taken prior to implant placement (T0) and at 12 months (T1). Baseline digital scans of models and DICOM files were superimposed to assess the periodontal phenotype.

RESULTS

Vertical bone changes from T0 to T1 were statistically significant (p = 0.013), with changes were significantly higher at the mesial (-0.31± 0.30 mm) and facial (p<0.05) sites. Horizontal dimensional changes 5 mm subcrestally were similar among different locations (p = 0.086) and the bone width loss was higher closest to the crest (p = 0.001). No correlation was found between soft tissue thickness and bone changes. However, bone thickness at baseline appears to influence the extent of horizontal bone remodeling. Overall, the magnitude of bone loss either vertically or horizontally was clinically insignificant (≤0.4 mm).

CONCLUSION(S)

Marginal bone changes in maxillary and mandibular posterior teeth following FTF at 12 months are very minimal, and mainly influenced by bone rather than soft tissue thickness. Overall, FTF does not seem to have deleterious effects on adjacent teeth periodontium. This article is protected by copyright. All rights reserved.

Immediate implant in the posterior region combined with alveolar ridge preservation and sealing socket abutment: A retrospective 3D radiographic analysis

BACKGROUND

Customized sealing socket abutment (SSA) has been claimed to optimize the peri-implant hard and soft tissues in type 1 implant placement. However, the evidence to claim the benefits of this technique over the use a conventional healing abutment remains weak.

PURPOSE

The aim of this retrospective study was to provide a 3D-radiographic evaluation of hard tissues changes following immediate implant placement in molar sites combined to ARP technique and installation of SSA.

MATERIALS AND METHODS

Baseline and follow-up (FU) CBCTs (from 1 to 5 years) of 26 patients were collected and included in the study. Baseline and FU CBCTs were superimposed and horizontal and vertical bone changes were assessed.

RESULTS

A total of 26 patients and 27 implants were included. Horizontal bone remodeling was not significant in any of the measured areas except in the most cervical level, where a mean bone remodeling of 0.73 mm was found. Proximal and buccal vertical bone changes were not significant.

CONCLUSIONS

Within the limits of a retrospective study, dimensional alveolar ridge changes 1 to 5 years after immediate implant placement in molar sites with simultaneous ARP technique and installation of SSA seem to be very limited.

Pocket elimination after osseous resective surgery: A systematic review and meta-analysis

AIM

To systemically review the available evidence on the clinical performance of osseous resective surgery (ORS) in the treatment of residual periodontal defects in terms of pocket elimination and biological costs in patients with chronic periodontitis.

MATERIALS AND METHODS

Three databases (PubMed, EMBASE and Cochrane) were searched up to January 2019. Clinical trials with a follow-up duration of at least 12 months after ORS with or without fibre retention technique were included. Quantitative synthesis was conducted with random-effect meta-analysis.

RESULTS

Overall, 1,765 studies were retrieved, of which 53 full-text articles were screened by two reviewers. Finally, a total of three RCTs were included in the meta-analysis. Random-effect meta-analysis showed a weighted mean percentage of pocket elimination (final PD ≤ 4 mm) at 12 months of 98.3% (95% CI: 96.8; 99.7) with I² of 26%. The weighted mean amount of resected bone was 0.87 mm (95% CI: 0.49; 1.25), and the weighted mean increase in gingival recession was 2.13 mm (95% CI: 1.49; 2.78) at 12 months.

CONCLUSIONS

ORS represents an effective surgical approach for the elimination of residual periodontal pockets in the short to medium term. Additional randomized controlled clinical trials with data on pocket elimination are warranted.

Stability of the gingival margin after an aesthetic crown lengthening procedure in the anterior region by means of a replaced flap and buccal osseous surgery: a prospective study

OBJECTIVES

The main objective of this study was to assess changes in the position of the gingival margin (GM) after performing an aesthetic crown lengthening (ACLP) by means of submarginal incisions, buccal osseous surgery, and a replaced flap after a healing period of 6 months.

METHODS

Twenty-one patients who needed a surgical crown lengthening in the maxillary anterior teeth were included. An individual stent was fabricated to record changes in the position of the GM. Clinical measurements were recorded pre-surgically; immediately post-surgically (baseline); and at 42, 90, and 180 days.

RESULTS

After the ACLP, the GM displacement did not change significantly after 42, 90, and 180 days (4.32 ± 1.17 mm, 4.29 ± 1.14 mm, and 4.26 ± 1.11 mm, respectively). Tissue rebound seems to be related to the distance from the GM to the alveolar bone (AB) at the time of suturing (GM-AB(X)). When GM-AB(X) was ≤ 2 mm, 3 mm, and ≥ 4 mm, the GM rebound at 6 months was 0.94 ± 0.53 mm, 0.10 ± 0.28 mm, and - 0.26 ± 0.40 mm, respectively. These differences were statistically significant (P < 0.001).

CONCLUSIONS

An ACLP releasing the flap up to the mucogingival junction, with a ≥ 3-mm distance from the bone crest to the gingival margin can lead to a stable GM position at 42, 90, and 180 days.

CLINICAL RELEVANCE

This article focuses on variables affecting the stability of the GM, which is a critical factor that may compromise the biological and aesthetic long-term outcomes.

Deproteinized bovine bone derived with collagen improves soft and bone tissue outcomes in flapless immediate implant approach and immediate provisionalization: a randomized clinical trial

OBJECTIVES

This study aimed at evaluating soft and hard tissue dimensions after immediate implant placement and immediate temporization with or without alveolar preservation at the maxillary anterior region.

MATERIALS AND METHODS

Twenty-two patients needing maxillary incisor extraction and with the possibility of immediate implant placement were randomly assigned to the following groups: test (n = 11): immediate implant placement + deproteinized bovine bone derived with collagen inserted into the alveolus or control (n = 11): immediate implant placement without biomaterial. All soft tissue measurements were evaluated at baseline, 3 months, and 6 months after implant therapy. Cone beam tomography was performed at baseline and at 6 months after implant placement to evaluate hard tissue dimension.

RESULTS

The test group presented higher height of soft tissue at mesiobuccal and distobuccal sites at 3 months and 6 months when compared to the control group (p < 0.05). Regarding the bone tissue, the test group showed higher buccolingual ridge dimension at 6 months when compared to the control group (p < 0.05).

CONCLUSIONS

It can be concluded that the use of deproteinized bovine bone derived with collagen together with immediate dental implants results in better soft and bone tissue outcomes than immediate implants alone.

CLINICAL RELEVANCE

The use of deproteinized bovine bone derived with collagen may enhance the results regarding soft and bone tissue in combination with immediate implant and temporization.

Anti-resorptive effect of pamidronate on extraction socket wall in dogs

AIM

The aim of this experimental in vivo investigation was to assess the anti-resorptive effect of low concentration pamidronate on the buccal plate in fresh extraction sockets.

MATERIALS AND METHODS

The distal roots of the third premolars were extracted bilaterally in six dogs. A collagen matrix loaded with either pamidronate (test group) or saline (control group) was positioned on the outer surface of buccal bone immediately after tooth extraction and subsequently covered with a coronally advanced flap. Histological and histomorphometric outcomes were evaluated 12 weeks later.

RESULTS

The mean vertical distance between the buccal and lingual bone crest differed significantly between the test and control groups (0.52 ± 0.43 and 2.21 ± 1.15 mm, respectively; p = .037). The width of the buccal bone 1 mm below the crest was significantly wider in the test group than the control group (4.68 ± 0.68 vs. 3.44 ± 0.60 mm, p < .001).

CONCLUSIONS

Local application of pamidronate onto a collagen matrix may reduce the dimensional changes of the buccal bone plate both vertically and horizontally.

Anatomical and Radiologic Evaluation of the Dimensions of Upper Molar Alveoli

PURPOSE

The aim of the present study was to analyze the alveolar bone morphology of the upper first and second molars. This analysis aims to evaluate the morphology of a hypothetical postextractive site in the upper molar area to diagnose the possibility of immediate postextraction implant placement.

MATERIALS AND METHODS

Cone-beam CT scans of 100 patients were examined. The measurements were made using a dedicated 3D software. Reference points were identified to allow clear and repeatable measurements.

RESULTS

The mean available height was 7.43 ± 3.40 mm for the upper first molars and 7.07 ± 3.09 mm for the upper second molars. The interradicular septum was present in first molars in 74% of cases and 44% of cases in upper second molars.

CONCLUSIONS

In most cases, the alveolar sites of the upper first and second molars do not present ideal conditions for immediate implant insertion in a correct position. The primary stabilization of a standard-sized dental implant is often difficult because of the minimum apical bone available. In particular, the interradicular septum, which often represents the ideal fixture position, is rarely adequately represented. Preoperative cone-beam scan and the knowledge of anatomical measurements from the present analysis are fundamental before planning immediate postextractive implants in the upper molar area.

Effect of incision design on interproximal bone loss of teeth adjacent to single implants. A randomized controlled clinical trial comparing intrasulcular vs paramarginal incision

PURPOSE

To evaluate the effect of incision design in implant surgery on interproximal bone loss of posterior teeth adjacent to interdental single implants, comparing intrasulcular and paramarginal incision. A further aim was to assess the influence of the incision technique on peri-implant bone remodeling.

MATERIALS AND METHODS

A controlled randomized clinical trial was carried out in a University Clinic. All the patients received an interdental posterior single implant. The incision type was randomly divided into two groups: (a) intrasulcular or (b) paramarginal. Standardized periapical digital radiographs were made with the parallel technique and a silicone index individualized in each patient. Radiographs were made immediately after implant placement, at abutment connection, 6 and 12 months post-loading. Two radiographic reference points were detected at the interproximal aspect of the adjacent teeth: (A) the cementoenamel junction and (B) the most coronal aspect of the bone crest. The interproximal bone loss of the adjacent teeth was calculated as the difference from A to B between the different follow-up periods and baseline. Two different examiners evaluated the radiographic measurements twice.

RESULTS

Sixty patients, each with one implant, were included, 30 in each group. A mean interproximal bone loss in teeth of 0.09 mm in the intrasulcular and 0.10 mm in the paramarginal group was found at 12 months post-loading. Mean peri-implant bone remodeling was 0.17 mm in the intrasulcular group and 0.15 mm in the paramarginal group. Differences between incision types were not statistically significant (p > .05).

CONCLUSIONS

Both incision designs used to place interdental single implants resulted in minimum bone loss at the interproximal aspect of adjacent teeth. The incision design did not significantly influence the radiographically assessed interproximal bone loss nor peri-implant bone remodeling.

Esthetic Assessment of Implants Placed into Fresh Extraction Sockets for Single-Tooth Replacements Using a Flapless Approach

BACKGROUND

To validate the concept of immediate implant placement and nonfunctional loading for use in the esthetically sensitive anterior maxilla, clinical trials should ideally include objective esthetic criteria.

PURPOSE

This study analyzed procedural results as graded by the pink esthetic score and white esthetic score (PES/WES).

METHODS

Thirty-nine suitable patients (mean follow-up 44.82 ± 28 months) were evaluated.

RESULTS

Thirty-eight implants fulfilled stringent criteria for successful osseointegration: absence of peri-implant radiolucency, implant mobility, suppuration, and pain. The mean total PES/WES was 15.50 ± 2.67 (range: 10-20). The mean total PES of 7.92 ± 1.60 (range: 5-10) indicated favorable overall peri-implant soft-tissue conditions. Root convexity and texture (1.63 ± 0.54) and curvature of the facial mucosa (1.68 ± 0.47) and distal papilla (1.66 ± 0.48) had the highest mean values, whereas acceptable levels of facial tissue (1.53 ± 0.73) and mesial papilla (1.42 ± 0.64) were the most difficult to fully achieve. The mean mesial and distal bone loss at data collection was, was 1.19 ± 0.54 and 1.15 ± 0.51, respectively. Periodontal disease severity (advanced chronic and aggressive periodontitis) was significantly associated with a low total PES (p = .048).

CONCLUSIONS

Objective PES/WES assessment validated immediate anterior maxillary single-tooth replacement and restoration as being a successful and esthetically predictable treatment modality in sites where the buccal bone had been preserved during the extraction at 1 year of follow-up.

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.

The Effect of Systemic Delivery of Aminoguanidine versus Doxycycline on the Resorptive Phase of Alveolar Bone Following modified Widman Flap in Diabetic Rats: A Histopathological and Scanning Electron Microscope (SEM) study

OBJECTIVES

Aminoguanidine (guanylhydrazinehydrochloride) is a drug that prevents many of the classical systemic complications of diabetes including diabetic osteopenia through its inhibitory activity on the accumulation of advanced glycation end -products (AGEs). The aim of the present study was to evaluate the effectiveness of aminoguanidine versus doxycycline in reducing alveolar bone resorption following mucoperiosteal flap in diabetic rats, using the conventional histopathology and scanning electron microscope (SEM).

METHODS

Twenty-seven male albino rats were used in this study. Periodontal defects were induced experimentally on lower anterior teeth. All rats were subjected to induction of diabetes, by IV injection of the pancreatic B-cells toxin alloxan monohydrate. After eight weeks following the establishment of periodontal defects in all rats, the ligation was removed and 3 rats were scarified as negative control (group 1). The remaining animals were divided into three group based on treatment applied following mucoperiosteal flap surgery. Group 2 received saline treatment only, group 3 received doxycycline periostat (1.5 mg/kg/day) for 3 weeks, and group 4 received aminoguanidine (7.3 mmol/kg) for 3 weeks. The fasting glucose level was measured weekly post operatively. After 21 days all rats were sacrificed. Three anterior parts of the mandible of each group was prepared for histopathological examination and two parts were prepared for SEM.

RESULTS

Aminoguanidine treated group (group 4) showed statistically significant increased new bone formation, higher number of osteoblasts and decrease osteoclasts number, resorptive lacunae and existing inflammatory cell infiltration as compared to positive control group (group 2) (P<0.05). Doxycycline was also effective in reducing bone loss as documental by histopathological study.

CONCLUSION

The present study showed that aminoguanidine was significantly effective in reducing alveolar bone loss and can modify the detrimental effects of diabetes in alveolar bone resorption.

Buccal bone deficiency in fresh extraction sockets: a prospective single cohort study

OBJECTIVE

The purpose of this prospective single cohort study was to evaluate the use of xenograft and collagen membranes in treating full or partial buccal bone defects of fresh extraction sockets in the esthetic zone.

MATERIALS AND METHODS

Thirty-three patients requiring tooth extraction in the anterior maxillary area and showing a complete or partial buccal bone plate deficiency (more than 2 mm) were consecutively enrolled and treated. Corticocancellous porcine bone and platelet-rich fibrin (PRF) with a collagen membrane were used to graft the extraction sockets, and the membranes were left exposed to the oral cavity with a secondary soft tissue healing. The outcome variables were as follows: width of keratinized mucosa, facial soft tissue levels, clinical bone changes (measured with a clinical splint), implant and prosthesis failures, and peri-implant marginal bone changes.

RESULTS

All treated sites allowed the placement of implants; the width of keratinized mucosa at the mid-facial aspect showed an increase of 2.3 mm 5 months after the grafting procedure, and its value was 3.2 ± 0.6 mm at 1-year follow-up. The mean values of the facial soft tissue level indicated an increase over time. The bone level showed an improvement of 0.8 ± 0.1 mm and 0.7 ± 0.1 mm at mesial and distal sites, respectively, when compared to the baseline measurements. Finally, in the palatal area, no bone changes were observed. No implant failed during the entire observation period.

CONCLUSIONS

Findings from this study showed that xenograft and PRF, used for ridge preservation of the extraction sockets with buccal bone plate dehiscence in the esthetic zone, can be considered effective in repairing bone defects before implant placement. The secondary soft tissue healing over the grafted sockets did not compromise bone formation; moreover, the soft tissue level and the width of keratinized gingiva showed a significant improvement over time.

The influence of the periodontal biotype on peri-implant tissues around immediate implants with and without xenografts. Clinical and micro-computerized tomographic study in small Beagle dogs

OBJECTIVE

Soft tissues and buccal bone plate remodeling after immediate implantation in sockets with thin buccal bone, using the flapless approach with or without bone graft into the buccal gap, was compared between sites with thin and normal gingiva.

MATERIAL AND METHODS

Eight dogs had the gingiva of one side of the mandible thinned, the mandibular premolars were extracted without flaps, and 4 implants were installed in each side, positioned 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). Buccal bone thickness (BBT), thickness of keratinized tissue (TKT), alveolar thickness (AT), gingival recession (GR), and probing depth (PD) were clinically evaluated. Within 12 weeks the dogs were sacrificed and the samples were analyzed by micro-computerized tomography.

RESULTS

A thin BBT was observed in all the dogs. The presurgical procedures reduced TKT in the test group, with minimal changes of the AT. There were no statistically significant differences among the groups for the clinical parameters and the tomographic analysis showed similar linear and tri-dimensional bone reduction in all the groups.

CONCLUSION

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

Tissue response following papilla-sparing and sulcular incisions in oral surgery--an experimental study

OBJECTIVES

The objective of this study is to compare tissue reduction following papilla-sparing and sulcular incisions in oral surgical indications.

MATERIAL AND METHODS

Five beagle dogs were used. Three months after tooth extraction of P2-M1, notches were prepared at the height of the interproximal gingiva into M2 and P1. Papilla-sparing and sulcular incisions were randomly performed, full-thickness flaps elevated and flaps repositioned. Three months postoperatively, tissue reduction was assessed using a digital calliper, mean values were calculated per group and analysed using a Wilcoxon matched-pair rank test.

RESULTS

Papilla-sparing incisions revealed significantly less (p < 0.05) tissue reduction than sulcular incision techniques.

CONCLUSION

Papilla-sparing incisions seem to induce less tissue response following flap surgery compared to sulcular incisions in oral surgical indications. Nevertheless, tissue reduction was seen in both groups.

CLINICAL RELEVANCE

For surgical approaches without the necessity of direct access to the root surface (i.e., implantology, oral surgery), papilla-sparing incisions may be superior compared to sulcular incisions.

Evaluation of healing following tooth extraction with ridge preservation using cortical versus cancellous freeze-dried bone allograft

BACKGROUND

The objective of this study is to compare histologic and clinical healing following tooth extraction and ridge preservation with either cortical or cancellous freeze-dried bone allograft (FDBA) in non-molar extraction sockets.

METHODS

Forty patients requiring implant placement were enrolled, with 20 patients randomly assigned to each group (cortical versus cancellous FDBA). All of the allograft materials were obtained from the same donor to control for variability between donors and processing. Patients returned after 17 to 21 weeks (average: 18.2 weeks), and a 2-mm-diameter core biopsy was obtained before implant placement. Histomorphometric analysis was performed to determine percentage of new bone formation, residual graft material, and non-mineralized connective tissue (CT)/other material. Clinical measurements of ridge dimensions were taken at the time of tooth extraction and again at implant placement.

RESULTS

There was no significant difference in new bone formation between the cortical and cancellous FDBA groups (P = 0.857). A significantly greater percentage of residual graft material was detected in the cortical FDBA group compared with the cancellous FDBA group (P = 0.019). A significantly greater percentage of non-mineralized CT/other material was found in the cancellous FDBA group compared with the cortical FDBA group (P = 0.040). The only significant clinical difference between groups was a greater loss of lingual ridge height in the cancellous group.

CONCLUSIONS

This is the first reported study to compare the histologic changes following tooth extraction with ridge preservation in humans using cortical versus cancellous FDBA. There were no differences in the percentage of new bone formation between the groups.

Clinical and radiographic evaluation of regenerative potential of GTR membrane (Biomesh®) along with alloplastic bone graft (Biograft®) in the treatment of periodontal intrabony defects

BACKGROUND AND OBJECTIVES

The primary goal of periodontal therapy is to restore the tooth supporting tissues lost due to periodontal disease. The aim of the present study was to compare the efficacy of combination of GTR membrane and alloplastc bone graft with open flap debridement (OFD) in treatment of periodontal intrabony defects.

METHODS

Twenty paired intrabony defects were surgically treated using split mouth design. The defects were randomly assigned to treatment with OFD, GTR membrane+bone graft (test) or OFD alone (control). The clinical efficacy of two treatment modalities was evaluated at 6 months postoperatively by clinical, radiographical parameters. The measurements included probing pocket depth (PD), clinical attachment level (CAL), gingival recession (GR), bone fill (BF), bone density (BD).

RESULTS

The mean reduction in PD at 0 to 6 months was 3.20±0.82 mm and CAL gain of 3.10±1.51 mm occurred in the GTR membrane+bone graft (test) group; corresponding values for OFD (control) were 2.10±0.63 mm and 1.90±0.57 mm. Similar pattern of improvement was observed when radiographically postoperative evaluation was made. All improvement in different parameters was statistically significant (p<0.01).

CONCLUSION

Treatment with a combination of collagen membrane and bone graft led to a significantly more favorable clinical outcome in intrabony defects as compared to open flap debridement alone.

Clinical evaluation of short and wide-diameter implants immediately placed into extraction sockets of posterior areas: a 2-year retrospective study

The objective of the study was to determine the short-term success rate of short and wide single-tooth implants, immediately placed into extraction sockets of the posterior area. A retrospective cohort study design was used. A total of 145 subjects received 162 short and wide-diameter single-tooth implants between 2006 and 2009. A minimal 7-mm residual height and 9-mm ridge width was available in all the implant sites, and the attached gingivae were at least 2 mm wide. All implants were placed and restored with the single crown by one experienced operator. The data were analyzed with descriptive statistics. All implants were placed in molar areas. There were 20 Ankylos implants with a diameter 5.5 or 7 mm and a length of 8 mm and 142 hydroxyapatite-coated implants with a diameter 5 or 6 mm and a length of 5.7 to 8 mm. One of the 162 implants failed before prosthetic restoration, resulting in a survival rate of 99.4% after loading. Patients were followed for up to 56 months (mean = 24 months) after loading of implants. The radiographic and clinical data revealed well-maintained hard and soft tissues with acceptable short-term results. For residual ridges with minimal height but adequate width, the immediate placement of short and wide-diameter implants in fresh extraction sockets may offer a simple and predictable treatment alternative if implants are positioned appropriately after a thorough preoperative analysis.

Tissue changes of extraction sockets in humans: a comparison of spontaneous healing vs. ridge preservation with secondary soft tissue healing

INTRODUCTION

As a consequence of extraction, the height of the buccal wall tends to decrease and results in the disappearance of bundle bone. To modify bone remodelling after extraction, various ridge preservation techniques have been proposed. The present research was drawn up with the following considerations in mind: to evaluate and to compare changes of hard and soft tissues in post-extraction sockets which received a ridge preservation procedure, with post-extraction sockets which had healed naturally.

MATERIALS AND METHODS

Each patient was randomly allocated to a test or control group using a specific software package. After extraction, the sockets were carefully inspected and any granulation tissue was removed. The control sites received silk sutures to stabilize the clot without any grafting material. The test sites were grafted with corticocancellous porcine bone and a collagen membrane. All experimental sites had the membranes left exposed to the oral cavity with a secondary wound healing. The thickness of the buccal alveolar bone, if present, was carefully measured at the time of tooth extraction using a calliper at 1 mm from the edge of the wall. The following clinical parameters were evaluated at baseline and after 4 months at implant placement: vertical bone changes, horizontal bone changes and width of keratinized gingiva. The length, diameter and need for additional bone augmentation were assessed for both groups at the time of implant insertion.

RESULTS

The control group showed vertical bone resorption of 1 ± 0.7 mm, 2.1 ± 0.6 mm, 1 ± 0.8 mm and 2 ± 0.73 mm at the mesial, vestibular, distal and lingual sites respectively. Moreover, changes in horizontal dimension showed an average resorption of 3.6 ± 0.72 mm. The test sites showed a horizontal bone remodelling of 0.3 ± 0.76 mm, 1.1 ± 0.96 mm, 0.3 ± 0.85 mm, 0.9 ± 0.98 mm at the mesial, vestibular, distal and lingual sites respectively. The horizontal bone resorption at the test sites was 1.6 ± 0.55 mm. The keratinized gingiva showed a coronal shift of 0.7 mm in the control group when compared to 1.1 mm in the test group. In addition, 42% of sites in the control group required an additional bone augmentation at implant placement, when compared to 7% in the test sites.

CONCLUSIONS

This study clearly points out that an alveolar ridge preservation technique performed with collagenated porcine bone and a resorbable membrane--according to the procedure reported in this study--was able to limit the contour changes after tooth extraction. Finally, the test sites showed a better preservation of facial keratinized tissue when compared to control sites; grafted sites allowed the placement of longer and wider implants when compared to implants inserted in non-grafted sites.

Local drug delivery of alendronate gel for the treatment of patients with chronic periodontitis with diabetes mellitus: a double-masked controlled clinical trial

BACKGROUND

Alendronate (ALN) increases alveolar bone density with systemic use and, has been found to increase bone formation on local delivery into the periodontal pocket. The purpose of the present study is to explore the efficacy of 1% ALN gel as a local drug delivery system in adjunct to scaling and root planing (SRP) for the treatment of intrabony defects in patients with chronic periodontitis (CP) with type 2 diabetes (DM) compared to a placebo gel.

METHODS

Seventy intrabony defects were treated with either 1% ALN or placebo gel. Clinical parameters were recorded at baseline, 2 months, and 6 months. Radiographic parameters were recorded at baseline and 6 months. Defect fill at baseline and 6 months was calculated on standardized radiographs using image analysis software.

RESULTS

Mean probing depth (PD) reduction and mean clinical attachment level (CAL) gain was greater in the ALN group than the placebo group at both 2 and 6 months. Furthermore, significantly greater mean percentage of bone fill was found in the ALN group (44.2% ± 11.78%) compared to the placebo group (2.8% ± 1.61%).

CONCLUSIONS

In patients with type 2 DM and CP, local delivery of 1% ALN into periodontal pockets resulted in a significant increase in the PD reduction, CAL gain, and improved bone fill compared to placebo gel as an adjunct to SRP. Thus, ALN can be used as an adjunct to SRP to provide a new dimension in the periodontal therapy in the near future.

Extraction socket preservation graft before implant placement with calcium sulfate hemihydrate and platelet-rich plasma: a clinical and histomorphometric study in humans

BACKGROUND

The aim of this investigation is to evaluate clinical and histologic outcome of using medical-grade calcium sulfate hemihydrate (MGCSH) mixed with platelet-rich plasma (PRP) for extraction socket preservation graft before implant placement.

METHODS

This study is a single-site, randomized and controlled investigation. Sixteen patients with a non-restorable tooth requiring extraction followed by implant placement were enrolled in this study. After extraction of a tooth, eight selected patients randomly received MGCSH mixed with PRP in the extraction sockets (test group), and eight selected patients randomly received collagen resorbable plug dressing material (control group). At the time of extraction and 3 months later (at implant placement surgery), vertical and horizontal socket dimensions were measured. Bone core samples were retrieved from the center of the healed socket before implant placement for histomorphometric analysis.

RESULTS

There was a statistically significant difference between the two groups based on histomorphometric analysis (P <0.05). New vital bone percentage regenerated after 3 months of healing was 66.5% ± 10.4% in sockets grafted with MGCSH mixed with PRP compared to 38.3% ± 9.3% collagen resorbable plug. There was no statistically significant difference in the amount of vertical and horizontal bone resorption (P >0.05) between groups. In all cases but two in the control group, implants were placed with primary stability.

CONCLUSION

MGCSH mixed with PRP showed greater vital bone volume at 3 months with rapid enhancement of bone healing compared to PRP-free collagen resorbable graft.

Flap vs. "flapless" surgical approach at immediate implants: a histomorphometric study in dogs

AIM

To compare the remodeling of the alveolar process at implants installed immediately into extraction sockets by applying a flap or a "flapless" surgical approach in a dog model.

MATERIAL AND METHODS

Implants were installed immediately into the distal alveoli of the second mandibular premolars of six Labrador dogs. In one side of the mandible, a full-thickness mucoperiosteal flap was elevated (control site), while contra-laterally, the mucosa was gently dislocated, but not elevated (test site) to disclose the alveolar crest. After 4 months of healing, the animals were sacrificed, ground sections were obtained and a histomorphometric analysis was performed.

RESULTS

After 4 months of healing, all implants were integrated (n=6). Both at the test and at the control sites, bone resorption occurred with similar outcomes. The buccal bony crest resorption was 1.7 and 1.5 mm at the control and the test sites, respectively.

CONCLUSIONS

"Flapless" implant placement into extraction sockets did not result in the prevention of alveolar bone resorption and did not affect the dimensional changes of the alveolar process following tooth extraction when compared with the usual placement of implants raising mucoperiosteal flaps.

Beta-tricalcium phosphate/type I collagen cones with or without a barrier membrane in human extraction socket healing: clinical, histologic, histomorphometric, and immunohistochemical evaluation

The aim of this study was to investigate the healing of human extraction sockets filled with β-tricalcium phosphate and type I collagen (β-TCP/Clg) cones with or without a barrier membrane. Twenty patients were divided in two groups: (A) β-TCP/Clg non-membrane and (B) β-TCP/Clg + barrier membrane. Clinical examination and biopsies from the grafted sites were collected 9 months later. Bone samples were analyzed using histomorphometry and immunohistochemistry. The horizontal dimension of the alveolar ridge was significantly reduced 9 months after socket preservation in the non-membrane group. There was bone formation with no significant differences between the two groups in the areas occupied by new bone (A = 42.4%; B = 45.3%), marrow (A = 42.7%; B = 35.7%), or residual graft (A = 9.7%; B = 12.5%). Immunohistochemistry revealed osteonectin expression in both groups. Both groups demonstrated sufficient amounts of vital bone and socket morphology to support dental implant placement after the 9-month healing period. A future trial to evaluate the alveolar outcomes at an earlier 6-month time point rather than the 9 months used in this study would be of interest.

Bone loss after full-thickness and partial-thickness flap elevation

OBJECTIVES

the aim of this study was to histologically assess whether elevation of partial-thickness flaps results in reduced bone alterations, as compared with full-thickness flap preparations.

MATERIAL AND METHODS

in five beagle dogs, both mandibular second premolars (split-mouth design) were subjected to one of the following treatments: Tx1: elevation of a partial-thickness flap over the mesial root of P(2) and performing a notch at the height of the bone. Tx2: elevation of a full-thickness flap over the mesial root of P(2) and performing a notch at the height of the bone. After 4 months, sections were evaluated for: (i) vertical bone loss and (ii) osteoclastic activity using histometry.

RESULTS

elevation of both full- and partial-thickness flaps results in bone loss and elevated osteoclastic activity. Partial-thickness flaps can result in less bone loss than full-thickness flaps, but are subject to some variability.

CONCLUSION

use of partial-thickness flaps does not prevent from all bone loss. The procedure may result most of the times in less bone loss than the elevation of full-thickness flaps. Further research has to evaluate the determinants of effective outcomes of partial-thickness flap procedures.

Immediate loading of a dental implant placed in fresh socket with acute dehiscence-type defect: a clinical case report

BACKGROUND

The aim of the present clinical case is to show buccal bone repair around a dental implant placed by flapless technique and immediately loaded in fresh socket with acute buccal dehiscence-type defect.

METHODS

A 58-year-old female presented with a fistula on the buccal side and a root fracture at the left lateral incisive. The dental extraction was performed without mucogingival flap elevation; the absence of buccal bone plate was recorded. A screw-shaped implant was placed. Immediately after the surgical procedure, the patient received temporary prosthetic restoration, and 3 months later definitive metal-ceramic restoration was positioned.

RESULTS

Four years later, a fracture of the crown and gingival inflammatory process were observed. The crown was removed and a fracture of the zirconia abutment was reported. Surgical reentry was performed, gingival flap was raised, and buccal bone repair was observed.

CONCLUSION

Biologically, it is very difficult to explain the bone repair process around implants in the acute dehiscence-type defect, and only biologic speculations explain the outcome of this clinical result.

Quantitative analysis of bone density in direct digital radiographs evaluated by means of computerized analysis of digital images

OBJECTIVES

minimal density variations of mineralized tissues can be reliably detected with quantitative image subtraction analysis. The aim of this study was to evaluate quantitative variations of in vitro mineral density by varying the exposure time of direct digital radiographs using a computer assisted densitometric image analysis (CADIA) program.

METHODS

in a human mandibular segment a three-wall periodontal defect was created mesial to a molar. Bone chips were created from the marrowbone of the same mandible with masses of 1 to 5 mg. A triplicate radiograph of the defect was taken as a baseline for seven different exposure times. The bone chips were inserted into the defect and another triplicate series of radiographs for the seven exposure times were taken as follow-up images. The images were analysed using CADIA software to detect variations in bone density.

RESULTS

the results of CADIA revealed increased density when the size of the inserted bone chip increased. The 2 mg chip was underestimated owing to mass reduction during insertion. The regression line of the CADIA values was consistent with the weight of the bone chips of 1, 3, 4 and 5 mg. The exposure time f6 (0.178 s) showed the best correlation with the bone chip weight. Loss of information in the images occurred when the exposure time exceeded the sensor's latitude.

CONCLUSIONS

CADIA analysis is a reliable and sensitive tool for detecting subtle bone density variations. More reliable results are obtained with increased exposure time; however, excessive exposure should be avoided.

Measurement of ridge alterations following tooth removal: a radiographic study in humans

OBJECTIVE

The aim of this study was a radiographic mesiodistal analysis of the shape of the bone crest 3 months after tooth removal.

MATERIAL AND METHODS

One hundred single tooth extractions were performed on 100 patients because of orthodontic or prosthetic causes. Bite blocks were used for two radiographs: one on the day of extraction and the other after healing of the socket, 3 months later. These X-rays were used to determine: (1) the most apical distance of alveolar ridge resorption, with baseline as the line between bone-to-teeth contact (the greatest distance in bone resorption height) and (2) the mesiodistal distance (MDD) and mesial and distal angles arising after bone tissue modeling.

RESULTS

Significant differences (P<0.05) emerged between the MDDs of multiple- [8 mm, 95% confidence interval (CI): 6.09, 9.90] and single-root teeth (5.60 mm, 95% CI: 4.80, 6.50). However, mesial or distal angles or the most apical distance of alveolar ridge resorption did not differ (mean distance in height=4.32 mm, 95% CI: 3.85, 4.78; mean angle=24 degrees ).

CONCLUSIONS

In this study, the post-extraction mesiodistal bone distance between teeth adjacent to the edentulous ridge depends on the size of the edentulous space. Nevertheless, the distance does not affect the distance in bone loss height. The distance of bone resorption height reaches a balance at the midpoint, which we consider indicative of stable healing. This resorption process must be considered when placing dental implants in fresh extraction sockets, especially in aesthetic sites, because the implant surfaces could be exposed after 3 months.

Clinical evaluation of regenerative potential of type I collagen membrane along with xenogenic bone graft in the treatment of periodontal intrabony defects assessed with surgical re-entry and radiographic linear and densitometric analysis

BACKGROUND AND OBJECTIVES

The primary goal of periodontal therapy is to restore the tooth supporting tissues lost due to periodontal disease. The aim of the present study was to compare the efficacy of combination of type I collagen (GTR membrane) and xenogenic bone graft with open flap debridement (OFD) in treatment of periodontal intrabony defects.

MATERIALS AND METHODS

Twenty paired intrabony defects were surgically treated using split mouth design. The defects were randomly assigned to treatment with OFD + collagen membrane + bone graft (Test) or OFD alone (Control). The clinical efficacy of two treatment modalities was evaluated at 9 month postoperatively by clinical, radiographical, and intrasurgical (re-entry) parameters. The measurements included probing pocket depth (PD), clinical attachment level (CAL), gingival recession (GR), bone fill (BF), bone density (BD) and intra bony component (INTRA).

RESULTS

The mean reduction in PD at 0-9 month was 3.3±0.82 mm and CAL gain of 3.40±1.51 mm occurred in the collagen membrane + bone graft (Test) group; corresponding values for OFD (Control) were 2.20±0.63 mm and 1.90±0.57 mm. Similar pattern of improvement was observed when radiographical and intra-surgical (re-entry) post operative evaluation was made. All improvement in different parameters was statistically significant (P< 0.01).

INTERPRETATION AND CONCLUSION

Treatment with a combination of collagen membrane and bone graft led to a significantly more favorable clinical outcome in intrabony defects as compared to OFD alone.