Semi-customized three-dimensional ultra-fine titanium meshes in guided bone regeneration for implant therapy in severe alveolar bone defect: a case report

This case report provides a detailed description of a simple and fast bone regeneration procedure using a semi-customized three-dimensional ultra-fine titanium mesh. A 50-year-old male with a severe vertical and horizontal bone defect in the anterior mandible underwent implant treatment in a staged approach. The autologous bone was combined with a xenograft, and the mixture was grafted to augment the bone defect and covered with semi-customized ultra-fine titanium meshes, which were selected among its various types according to size and configuration of the bone defect, directly connected and immobilized on the tenting screws with minimal shaping. In a postoperative 6 months re-entry surgery, the performed titanium meshes were removed, implants were placed, and a bone core biopsy was obtained that demonstrated satisfactory new bone formation. Finally, two months later, the definitive prosthesis was installed. This semi-customized ultra-fine titanium mesh could help an implant clinician obtain more predictable results in the guided bone regeneration (GBR).

A novel investigational preclinical model to assess fluence rate for dental oral craniofacial tissues

OBJECTIVE

Photodynamic Therapy (PDT) and Photobiomodulation (PBM) are recognized for their potential in treating head and neck conditions. The heterogeneity of human tissue optical properties presents a challenge for effective dosimetry. The porcine mandible cadaver serves as an excellent model and has several similarities to human tissues of the dental oral craniofacial complex. This study aims to validate a novel modeling system that will help refine PDT and PBM dosimetry for the head and neck region.

METHODS AND MATERIALS

Light transmission was analyzed through several tissue combinations at distances of 2 mm to 10 mm. Maximum light fluence rates (mW/cm2) were compared across tissue types to reveal the effects of tissue heterogeneity.

RESULTS

The study revealed that light fluence is affected by tissue composition, with dentin/enamel showing reduced transmission and soft tissue regions exhibiting elevated values. The porcine model has proven to be efficient in mimicking human tissue responses to light, enabling the potential to optimize future protocols.

CONCLUSION

The porcine mandible cadaver is a novel model to understand the complex interactions between light and tissue. This study provides a foundation for future investigations into dosimetry optimization for PDT and PBM.

Three-dimensional printing of the human lung pleural cavity model for PDT malignant mesothelioma

OBJECTIVE

The primary aim was to investigate emerging 3D printing and optical acquisition technologies to refine and enhance photodynamic therapy (PDT) dosimetry in the management of malignant pleural mesothelioma (MPM).

MATERIALS AND METHODS

A rigorous digital reconstruction of the pleural lung cavity was conducted utilizing 3D printing and optical scanning methodologies. These reconstructions were systematically assessed against CT-derived data to ascertain their accuracy in representing critical anatomic features and post-resection topographical variations.

RESULTS

The resulting reconstructions excelled in their anatomical precision, proving instrumental translation for precise dosimetry calculations for PDT. Validation against CT data confirmed the utility of these models not only for enhancing therapeutic planning but also as critical tools for educational and calibration purposes.

CONCLUSION

The research outlined a successful protocol for the precise calculation of light distribution within the complex environment of the pleural cavity, marking a substantive advance in the application of PDT for MPM. This work holds significant promise for individualizing patient care, minimizing collateral radiation exposure, and improving the overall efficiency of MPM treatments.

Facially Driven Digital Workflow for Maxillary and Mandibular Milled Implant- Retained Overdentures Using Two Different Unsplinted Attachment Systems: Case Report

Unsplinted attachment systems for implant overdentures offer various benefits for edentulous patients, including cost-effectiveness, enhanced cleansability, and less need for manual dexterity. This article describes a facially driven digital workflow for fabricating a maxillary implant overdenture retained by conometric-style attachments (Atlantis® Conus) with a palateless design opposing an implant overdenture retained by standard attachments (LOCATOR®). This procedure provides a predictable and accurate technique to digitally scan the master casts with wax rims for articulation and to guide the digital teeth design set-up for a predictable esthetic outcome. The removable prosthesis workflow involves virtual teeth set-up, a 3D-printed trial denture, a milled definitive prosthesis, and intraoral pick-up for both unsplinted attachment systems. The clinical and laboratory steps are described.

A Periodontal Perspective on the Successful Treatment of Recurrent Benign Gingival Lesions Affecting the Anterior Dentition: Two Case Reports

Recurrent benign gingival lesions occurring in the anterior dentition are clinical dilemmas. While complete removal of such lesions is required to prevent recurrence, this can result in a poor esthetic outcome. Relative to this conundrum, this report discusses the diagnosis, psychologic management, and clinical treatment of two patients with recurring lesions on the facial gingiva of the mandibular and maxillary incisors, respectively. Patient A, a 55-year-old woman, presented with a recurrent peripheral ossifying fibroma (POF); Patient B, a 76-year-old man, presented with a recurrent pyogenic granuloma (PG). Both patients underwent multiple procedures and were ultimately treated without lesion recurrence. The efficacious surgical treatment of recurrent gingival lesions like POF and PG requires an aggressive approach involving lesion removal of the lesion as well as a 1.0- to 2.0-mm margin of normal tissue, underlying alveolar bone, and associated periodontal ligament (PDL). The rationale for this approach stresses the potential periodontal and esthetic ramifications that were considered. In summary, when recurrent benign gingival lesions are localized to the anterior part of the mouth, the approach to their surgical removal should be modified to minimize the extent of gingival recession and other potential esthetic issues.

Reliability of Cone Beam Computed Tomography in Predicting Implant Treatment Outcomes in Edentulous Patients

Since the development of CBCT has been utilized in dentistry, the images of the CBCT can assist the surgeon to evaluate the anatomy carefully. Despite the value of radiology evaluation, implant procedures may require additional consideration rather than only evaluating the anatomical factors. The purpose of this study is to evaluate the predictability of using CBCT alone to plan for implant placement in edentulous patients digitally. CBCT images were analyzed by clinicians, measuring the maxillary and mandibular ridge heights and widths digitally of four predetermined implant sites in the maxillary and two selected implant sites in the mandibular arches of 91 patients planning for implant-supported overdenture. A total of 47 patients out of the 91 had completed implant placement on the edentulous ridge, contributing to 55 upper and/or lower arches (136 dental implants). Both predictabilities are low, implying that CBCT planning for implant placement on the edentulous ridge is not a good index and is insufficient to predict the surgical procedures as a solo method. The findings of this study indicate that digital planning by CBCT is insufficient to serve as an individual tool to predict implant procedures. Further information and evaluation must be considered for implant placement in the edentulous ridge.

Photobiomodulation in dental extraction therapy: Postsurgical pain reduction and wound healing

BACKGROUND

This scoping review and analysis were designed to assess the amount of time spent delivering photobiomodulation (PBM) light therapy after dental extraction to improve postoperative pain and wound healing.

TYPES OF STUDIES REVIEWED

The scoping review was performed according to the Cochrane Collaboration and Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. Publications were specific for human randomized controlled clinical trials, PBM after dental extraction therapy, and related clinical outcomes. Online databases searched included PubMed, Embase, Scopus, and Web of Science. Analyses were conducted to analyze the prescribed intervals of time (seconds) per application of PBM.

RESULTS

Of the 632 studies initially identified, 22 studies fulfilled the inclusion criteria. Postoperative pain and PBM were reported in 20 articles for 24 treatment groups, with treatment times ranging from 17 through 900 seconds and wavelengths from 550 through 1,064 nm. Clinical wound healing outcomes were reported in 6 articles for 7 groups with treatment times ranging from 30 through 120 seconds and wavelengths from 660 through 808 nm. PBM therapy was not associated with adverse events.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

There is future potential to integrate PBM after dental extraction therapy to improve postoperative pain and clinical wound healing. The amount of time spent delivering PBM will vary by wavelength and the type of device. Further investigation is needed to translate PBM therapy into human clinical care.

Ceramic Dental Implants: A Systematic Review and Meta-analysis

Purpose: To evaluate the performance of one- and two-piece ceramic implants regarding implant survival and success and patient satisfaction. Materials and Methods: This review followed the PRISMA 2020 guidelines using PICO format and analyzed clinical studies of partially or completely edentulous patients. The electronic search was conducted in PubMed/MEDLINE using Medical Subject Headings (MeSH) keywords related to dental zirconia ceramic implants, and 1,029 records were received for detailed screening. The data obtained from the literature were analyzed by single-arm, weighted meta-analyses using a random-effects model. Forest plots were used to synthesize pooled means and 95% CI for the change in marginal bone level (MBL) for short-term (1 year), mid-term (2 to 5 years), and long-term (over 5 years) follow-up time intervals. Results: Among the 155 included studies, the case reports, review articles, and preclinical studies were analyzed for background information. A meta-analysis was performed for 11 studies for one-piece implants. The results indicated that the MBL change after 1 year was 0.94 ± 0.11 mm, with a lower bound of 0.72 and an upper bound of 1.16. For the mid term, the MBL was 1.2 ± 0.14 mm with a lower bound of 0.92 and an upper bound of 1.48. For the long term, the MBL change was 1.24 ± 0.16 mm with a lower bound of 0.92 and an upper bound of 1.56. Conclusion: Based on this literature review, one-piece ceramic implants achieve osseointegration similar to titanium implants, with a stable MBL or a slight bone gain after an individual initial design depending on crestal remodeling. The risk of implant fracture is low for current commercially available implants. Immediate loading or temporization of the implants does not interfere with the course of osseointegration. Scientific evidence for two-piece implants is rare.

Improving Titanium Implant Stability with Photobiomodulation: A Review and Meta-Analysis of Irradiation Parameters

Objective: This analysis was designed to present a summary of available evidence that will inform practice and guide future research for photobiomodulation (PBM) after titanium implant placement procedures. Materials and methods: A systematic review was performed according to the Cochrane Collaboration and in line with Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) criteria. Two investigators screened the titles and abstracts, and reviewed articles for risk of bias. Online databases searched included PubMed, Embase, Scopus, and Web of Science. Terms were specific to the effects of PBM on dental implant stability. Results: Eight hundred fifty-six studies were identified, and 15 studies fulfilled the inclusion criteria. Light sources included both laser and light emitting diode (LED) devices. Wavelengths ranged from 618 to 1064 nm. The meta-analysis concluded that all 15 published studies were able to safely apply PBM near dental implants without adverse events. Laser and LED wavelengths that reported significant results included 618, 626, 830, 940 (2 × ), and 1064 nm. Conclusions: The use of adjunctive PBM can be safely prescribed after surgical placement of titanium implants. Six groups reported statistical significance for improving implant stability (four laser diode, two LED) in wavelengths ranging from 618 to 1064 nm. The amount of time spent delivering PBM was not a variable that differentiated whether a study reported significant results.

Validating Homogeneity for a Novel 3-Dimensional Tissue Phantom Modeling System of the Human Maxilla

Silicon phantom models have been utilized to calculate light fluence in patients being treated with Photodynamic Therapy (PDT). This application can be utilized for other non-ionizing wavelength therapies such as Photobiomodulation (PBM). We have developed a novel protocol to validate homogeneity for 3-dimensional silicon phantom models of the human maxilla. Accurately quantifying the light profiles of human tissue can accommodate for varying optical properties that occur between subjects. More importantly, this can help optimize light fluence dosimetry calculations to achieve intended results. Silicon models of identical composition were fabricated into two different shapes: 1 flat-planar cylindrical shaped model, 2) non-flat planar (3-dimensional) mold of the human maxilla. Fabricating homogenous silicon phantom models continues to be a challenge as micro-bubbles can contaminate the compound during the curing process. Integrating both proprietary CBCT and handheld surface acquisition imaging devices confirmed our results to be within 0.5mm of accuracy. This protocol was specifically used to cross-reference and validate homogeneity at various depths of penetration. These results present the first known successful validation of identical silicon tissue phantoms with a flat-planar surface vs. a non-flat 3D planar surface. This proof-of-concept phantom validation protocol is sensitive to the specific variations of 3-dimensional surfaces and can be applied to a workflow used to capture accurate light fluence calculations in the clinical setting.

PDT Light Fluence Phantom Modeling of the Human Pleural Cavity: A Proof-of-Concept Pre-Clinical Study

We have developed a novel scanning protocol for a life-sized human phantom model using handheld three-dimensional (3D) surface acquisition devices. This technology will be utilized to develop light fluence modeling of the internal pleural cavity space during Photodynamic Therapy (PDT) of malignant mesothelioma. The external aspect of the chest cavity phantom was prefabricated of a hardened synthetic polymer resembling ordinary human anatomy (pleural cavity space) and the internal aspect remained hollow without any characterizations. Both surfaces were layered with non-reflective adhesive paper to create non-uniformed surface topographies. These surface characteristics were established in randomized X-Y-Z coordinates ranging in dimensions from 1-15mm. This protocol utilized the handheld Occipital Scanner and the MEDIT i700. The Occipital device required a minimum scanner-to-surface distance of 24cm and the MEDIT device 1cm respectively. The external and internal aspects of the phantom model were successfully scanned acquiring digital measurements in actual value and converted into a digital image file. The initial surface rendering was acquired by the Occipital device and applied with proprietary software to guide the MEDIT device to fill voided areas. This protocol is accompanied by a visualization tool that allows for real-time inspection of surface acquisition in 2D and 3D. This scanning protocol can be utilized to scan the pleural cavity for real-time guidance for light fluence modeling during PDT, which will be expanded to ongoing clinical trials.

Healed Edentulous Sites: Suitability for Dental Implant Placement, Need for Secondary Procedures, and Contemporary Implant Designs

PURPOSE

The purpose of this retrospective computed tomography study was to evaluate bone availability for dental implant placement, frequency of bone augmentation procedures, frequency of anatomical structures that compromise implant placement, and frequency of implant dimensions, and to determine which edentulous sites would benefit from the use of a sloped implant versus a traditional flat design.

MATERIALS AND METHODS

Recorded parameters included the width of the ridge, the buccal and lingual/palatal alveolar bone height in reference to different anatomical landmarks, determination of implant placement, selection of an implant with a flat or sloped top, and need for a secondary bone augmentation procedure.

RESULTS

One thousand three hundred seventy edentulous sites were evaluated in 216 patients. Implants could be placed in 60.6% of the total sites, where the coronal portion would be sloped in 59% of sites and conventionally flat in 41%; 39.4% of sites were not adequate for implant placement, where 56.5% needed additional guided bone regeneration procedures and 43.5% required sinus augmentation procedures. The inferior alveolar canal was the most frequent anatomical structure limiting size and/or placement.

CONCLUSION

The study indicates that implants can be placed in slightly over half of edentulous sites without a secondary grafting procedure. The possibility of dental implant placement varied according to the volume and morphology of alveolar bone and related anatomical structures. This decreased from anterior to posterior in both arches. The sloped implant design was beneficial. In addition, the sloped implant design resulted in the placement of a longer implant.

The Long-Term Evaluation of Two-Unit Fixed Partial Dentures on Short, Threaded Implants: Delayed Versus Immediate Loading

Placement of short implants is a common approach to rehabilitate edentulous areas. The objective of this study was to evaluate the long-term survival of 7.0- and 8.5-mm implants placed in either a delayed or immediate loading protocol. Life table analysis revealed the implants treated with the delayed loading protocol had a 90.9% survival rate and the implants treated with the immediate loading protocol had a survival rate of 92.0%. The results of this 8-year prospective study demonstrate similar survival rates of short, cylindrical threaded implants placed by either a delayed or immediate loading protocol.

Diabetic Serum Inhibits Osteoblast Adhesion to Titanium Surface Through Advanced Glycation End Products: An In Vitro Study

PURPOSE

Diabetes mellitus has been shown to delay osseointegration of titanium dental implants. This study tested the hypothesis that serum derived from diabetes negatively affects osteoblast adhesion to polystyrene and titanium surfaces, partly through the presence of advanced glycation end products (AGEs).

MATERIALS AND METHODS

Twenty-four Sprague-Dawley rats were divided into three groups: normoglycemic control, streptozotocin-induced diabetic group, and diabetic group treated with the AGE inhibitor aminoguanidine. Polystyrene or titanium disks were preincubated in serum derived from each group. Human osteoblasts transfected with green fluorescent protein (GFP) were cultured, and the number of adherent osteoblasts was quantified. High-pressure liquid chromatography (HPLC) was used to fractionate eluates, which were further characterized by western blot with AGE antibody and adhesion assays. In parallel, sera derived from healthy patients, patients with controlled diabetes, and patients with uncontrolled diabetes were utilized for osteoblast adhesion assay and western blot.

RESULTS

Diabetic serum significantly reduced the number of adherent osteoblast and osteoblast aggregates on titanium disks, whereas aminoguanidine-treated serum rescued the effect of diabetes on the number of adherent osteoblast aggregates. Fractionated diabetic serum revealed distinct AGE bands at ~100 kDa and 44 kDa, whereas healthy serum did not express any. In human serum samples, both controlled and uncontrolled diabetes led to a significant reduction in the number of adherent osteoblasts on polystyrene and titanium surfaces compared with normoglycemic serum. This correlated with presence of AGEs in western blot in diabetic but not in healthy serum.

CONCLUSION

Osteoblast adhesion on the titanium surface was greatly reduced by the exposure of serum derived from diabetic rats or humans. Recovery of osteoblast aggregates by aminoguanidine treatment suggests that AGEs played a role in this negative effect. The correlating presence of AGEs from the fractionated sera of diabetic rats or humans and impaired osteoblast adhesion on the titanium surface further supports this role.

Effects of Conventional Synthetic Disease-Modifying Antirheumatic Drugs on Response to Periodontal Treatment in Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) and periodontitis are common chronic inflammatory diseases and periodontitis is known to be more common and more severe in patients with RA. Based on a paucity of studies about the relationship between common conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and periodontitis, this prospective study aimed to evaluate the adjunctive effect of csDMARDs on response to nonsurgical periodontal treatment in patients with RA. Thirty-two patients with RA (RA group) and 32 systemically healthy patients (control group) with periodontitis were included in this study. The RA group patients were treated with csDMARDs, such as methotrexate, hydroxychloroquine, and sulfasalazine. Conventional nonsurgical periodontal treatment with scaling and root planing was performed in both groups. The extent and severity of periodontitis were evaluated by plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) at baseline and 4 weeks after periodontal treatment. There was no statistically significant difference of periodontal parameters between the RA and control groups at baseline. Four weeks after scaling and root planing, PD reduction, and CAL gain were higher in the RA group treated with csDMARDs compared to the control group, and the difference was statistically significant (P = 0.006 and 0.003, respectively). A post hoc analysis of the RA group showed no statistically significant difference on the response to nonsurgical periodontal treatment in multiple csDMARDs therapy and addition of NSAIDs and/or steroids to csDMARDs. In patients with RA, csDMARDs showed beneficial effect on periodontal clinical parameters following the nonsurgical periodontal treatment.

Surgical Alternatives for Treating Peri-implantitis

The objective of this case series was to describe surgical approaches that can be used to efficiently and effectively treat peri-implantitis as measured by positive changes in clinical parameters. A total of 32 patients with 45 implants were treated surgically to eliminate peri-implantitis. Baseline clinical parameters measured prior to surgery were compared to those made 6 months postsurgery to evaluate the efficacy of each procedure. Implants demonstrating signs of peri-implantitis were treated by one of three approaches: (1) regenerative surgery, (2) osseous resective surgery, or (3) apically repositioned flap surgery. In all instances, the exposed implant surfaces were debrided and decontaminated. Relative to baseline values, regenerative surgery yielded statistically significant changes in probing depth (PD) (7.21 ± 0.27 mm to 4.09 ± 0.14 mm) and percentage of sites exhibiting bleeding on probing (BoP) (100.0% ± 0.0% to 10.6% ± 3.3%) as measured at the 6-month recall visit (P ≤ .05). The decrease in probing depth was not dependent on the type of graft material used (P ≤ .05). Resective surgery yielded statistically significant changes in PD (5.86 ± 0.23 mm to 3.63 ± 0.14 mm) and the percentage of sites exhibiting BoP (100.0% ± 0.0% to none) (P ≤ .05). Finally, the implants treated via apically repositioned flap surgery demonstrated statistically significant decreases (P ≤ .05) in both PD (6.79 ± 0.27 mm to 4.32 ± 0.16 mm) and BOP (100.0% ± 0.0% to 14.3% ± 6.7%) (P ≤ .05). Regenerative, resective, and apically positioned flap surgery can be utilized to successfully treat peri-implantitis.

Morphometric Changes Induced by Cold Argon Plasma Treatment on Osteoblasts Grown on Different Dental Implant Surfaces

Treatments for enhancing surface energy were studied in an effort to create a more favorable environment for cell adhesion. Cold argon plasma (CAP) is able to improve titanium-cell contact, producing hydrophilic surfaces with higher wettability. The aim of this in vitro study was to estimate the early cell morphology after CAP treatment of different commercially available titanium surfaces. Surface wettability was significantly augmented in all the treated samples. The authors investigated how CAP affected the behavior of osteoblasts by evaluating the cell morphology outcome. Cell surface areas differed in a statistically significant way when plasma-treated samples were compared to the untreated ones. The positive effect of CAP was shown on smooth, moderately rough, and rough implant surfaces.

The Use of Recombinant Human Platelet-Derived Growth Factor for Maxillary Sinus Augmentation

The maxillary sinus augmentation procedure has become a predictable treatment to regenerate bone for implant placement. The purpose of this study was to evaluate the effect of recombinant human platelet-derived growth factor BB (rhPDGF-BB) combined with a deproteinized cancellous bovine bone graft for sinus augmentation. The lateral window approach was used for maxillary sinuses with minimal residual bone. After a healing period of 4 months, dental implants were placed and then restored following a 2-month osseointegration period. The result demonstrated increased bone height and ISQ values and a 100% survival rate. This study indicates that the addition of rhPDGF-BB to deproteinized cancellous bovine bone accelerated the healing period in maxillary sinuses with minimal native bone.

Alveolar Ridge Augmentation with Three-Dimensional Printed Hydroxyapatite Devices: A Preclinical Study

The objective of this study was to evaluate the effectiveness of precise three-dimensional hydroxyapatite printed micro- and macrochannel devices for alveolar ridge augmentation in a canine model. All grafts induced minimal inflammatory and fibrotic reactions. Examination of undecalcified sections revealed that both types of grafts demonstrated bone ingrowth. The majority of the bone growth into the block graft was into the channels, though a portion grew directly into the construct in the form of small bony spicules. In conclusion, bone ingrowth was readily demonstrated in the middle of the implanted printed devices.

Effects of nerve cells and adhesion molecules on nerve conduit for peripheral nerve regeneration

Background

For peripheral nerve regeneration, recent attentions have been paid to the nerve conduits made by tissue-engineering technique. Three major elements of tissue-engineering are cells, molecules, and scaffolds.

Methods

In this study, the attachments of nerve cells, including Schwann cells, on the nerve conduit and the effects of both growth factor and adhesion molecule on these attachments were investigated.

Results

The attachment of rapidly-proliferating cells, C6 cells and HS683 cells, on nerve conduit was better than that of slowly-proliferating cells, PC12 cells and Schwann cells, however, the treatment of nerve growth factor improved the attachment of slowly-proliferating cells. In addition, the attachment of Schwann cells on nerve conduit coated with fibronectin was as good as that of Schwann cells treated with glial cell line-derived neurotrophic factor (GDNF).

Conclusions

Growth factor changes nerve cell morphology and affects cell cycle time. And nerve growth factor or fibronectin treatment is indispensable for Schwann cell to be used for implantation in artificial nerve conduits.

Comparison of ridge expansion and ridge splitting techniques for narrow alveolar ridge in a Swine cadaver model

Ridge splitting and ridge expansion have been used to expand narrow alveolar ridges. Piezosurgical ridge splitting involves separating the atrophic crests with piezosurgical inserts. Ridge expansion with motor-driven expanders was proposed to achieve the cortical dilation. The purpose of this study was to evaluate the efficacy of ridge gain by ridge expansion or ridge splitting. Eighteen (36 ramus) swine cadaver jaws were first divided into two groups- ridge expansion with a motor-driven expander or ridge splitting with the piezosurgical system. Then, either an active-tapping implant or nonactivetapping cylinder-type implant was inserted. The crestal ridge diameter change was measured with a Boley gauge. The area of bony perforation, which includes fenestrations and dehiscences, was measured with a prefabricated reference grid. The results showed that there was no statistically significant difference in crestal width gain between groups. However, the combination of the motor-driven ridge expansion technique and the active-tapping implant could be beneficial in significantly decreasing the bony perforation area.

Periodontal Regeneration - Intrabony Defects: Practical Applications From the AAP Regeneration Workshop

Focused Clinical Question: What are important considerations for selecting a predictable regenerative surgical approach for intrabony defects? Summary: The predictable regeneration of intrabony defects remains an important goal in the management of periodontitis. Clinical and histologic evidence of periodontal regeneration has been shown for multiple regenerative therapies, including bone replacement grafts, guided tissue regeneration, and biologics, when used alone or in combination. Regenerative therapies improve periodontal health, as evidenced by gains in clinical attachment level, reductions in probing depth, and gains in radiographic bone fill. Important patient-related factors (e.g., smoking) and defect/site-related factors (e.g., defect morphology and gingival biotype) can influence the potential to achieve periodontal regeneration. The regeneration of intrabony defects generally becomes more challenging with increasing loss of height, proximity, and number of bony walls. Therefore, combination therapies may be necessary to achieve predictable regeneration. Clinical improvements after regenerative therapy can be maintained over extended periods (≥10 years) with professional maintenance at appropriate intervals and adequate home care. Conclusions: Periodontal regeneration of intrabony defects is possible using a variety of regenerative strategies. Management should be coupled with an effective oral hygiene and supportive periodontal maintenance program for long-term success.

Periodontal regeneration - intrabony defects: a consensus report from the AAP Regeneration Workshop

BACKGROUND

Treatment of intrabony defects is an important therapeutic goal of periodontal therapy. The goal of this consensus report was to critically appraise the evidence for the available approaches for promoting periodontal regeneration in intrabony defects. In addition to evaluating the effectiveness of new regenerative approaches for intrabony defects, recommendations for future research were defined for this area.

METHODS

A systematic review was conducted using computerized searches of PubMed and Cochrane databases, supplemented with screening of references in original reports, review articles, and a hand search in selected journals. All searches were focused on regenerative approaches with histologic evidence of periodontal regeneration (proof of principle), clinical trials, and case reports. For purposes of analysis, change in intrabony defect fill was considered the primary outcome variable, with change in clinical attachment as a secondary outcome. The SORT (Strength of Recommendation Taxonomy) grade was used to evaluate the quality and strength of the evidence. During the consensus meeting, the group agreed on the outcomes of the systematic review, pertinent sources of evidence, clinical recommendations, and areas requiring future research.

RESULTS

The systematic review, which was conducted for the consensus conference, evaluated the effectiveness of the use of biologics for the treatment of intrabony defects. Enamel matrix derivative (EMD) and recombinant human platelet-derived growth factor-BB (rhPDGF-BB) with β-tricalcium phosphate were shown to be efficacious in regenerating intrabony defects. The level of evidence is supported by multiple studies documenting effectiveness. The clinical application of biologics supports improvements in clinical parameters comparable with selected bone replacement grafts and guided tissue regeneration (GTR). Factors negatively affecting regeneration included smoking and excessive tooth mobility.

CONCLUSIONS

Periodontal regeneration in intrabony defects is possible on previously diseased root surfaces, as evidenced by a gain in clinical attachment, decreased pocket probing depth, gain in radiographic bone height, and overall improvement in periodontal health. These clinical findings are consistent with available histologic evidence. Clinical improvements can be maintained over long periods (>10 years). Although bone replacement grafts have been the most commonly investigated modality, GTR, biologics, and combination therapies have also been shown to be effective. Future research should emphasize patient-reported outcomes, individual response differences, and emerging technologies to enhance treatment results.

CLINICAL RECOMMENDATIONS

Early management of intrabony defects with regenerative therapies offers the greatest potential for successful periodontal regeneration. The clinical selection and application of a regenerative therapy or combination of therapies for periodontal regeneration should be based on the clinician's experiences and understanding of the regenerative biology and technology. This decision-making process should take into consideration the potential adverse influence of factors, such as smoking, poor oral hygiene, tooth mobility, and defect morphology, on regeneration. Management should be coupled with an effective maintenance program for long-term success.

Factors affecting treatment planning decisions for compromised anterior teeth

The purpose of this study was to identify the factors that create differences in opinion between dental professionals when treatment planning for a patient whose problem is limited to one or more maxillary incisors. A series of computer-generated scenarios was created in which anterior teeth were compromised for various reasons. The cases were used to survey a diverse group of practitioners regarding whether to treat or extract a tooth under the given circumstances. The results indicated that numerous patient-associated factors had statistically significant effects on the decision-making process. These included the patient's age, root length, root morphology, periodontal status, history of prior endodontic treatment, presence of posts, and size of periapical radiolucencies. The data also showed that a clinician's educational background had a dramatic impact on his or her treatment recommendation.

Locally delivered salicylic acid from a poly(anhydride-ester): impact on diabetic bone regeneration

Diabetes mellitus (DM) involves metabolic changes that can impair bone repair, including a prolonged inflammatory response. A salicylic acid-based poly(anhydride-ester) (SA-PAE) provides controlled and sustained release of salicylic acid (SA) that locally resolves inflammation. This study investigates the effect of polymer-controlled SA release on bone regeneration in diabetic rats where enhanced inflammation is expected. Fifty-six Sprague-Dawley rats were randomly assigned to two groups: diabetic group induced by streptozotocin (STZ) injection or normoglycemic controls injected with citrate buffer alone. Three weeks after hyperglycemia development or vehicle injection, 5mm critical sized defects were created at the rat mandibular angle and treated with SA-PAE/bone graft mixture or bone graft alone. Rats were euthanized 4 and 12weeks after surgery, then bone fill percentage in the defect region was assessed by micro-computed tomography (CT) and histomorphometry. It was observed that bone fill increased significantly at 4 and 12weeks in SA-PAE/bone graft-treated diabetic rats compared to diabetic rats receiving bone graft alone. Accelerated bone formation in normoglycemic rats caused by SA-PAE/bone graft treatment was observed at 4weeks but not at 12weeks. This study shows that treatment with SA-PAE enhances bone regeneration in diabetic rats and accelerates bone regeneration in normoglycemic animals.

The effect of cigarette smoking and native bone height on dental implants placed immediately in sinuses grafted by hydraulic condensation

The purpose of this study was to determine the effect of cigarette smoking and residual native bone height on the survival of dental implants placed immediately in grafted sinuses. In this retrospective study, 334 subject records were screened, and 75 subjects (155 implants) were included. Data collection based on treatment notes and radiographs included age, sex, smoking status, sinus floor bone height, dental implant information, and implant survival. The survival rates of implants for nonsmokers and smokers at stage-two surgery were 93% and 84%, respectively. After 12 months of functional loading, the survival rates of implants for nonsmokers and smokers were 87% (81 of 93) and 79% (49 of 62), respectively (P < .000). Analysis revealed that the effect of smoking on implant survival is significant when the preoperative bone height is less than 4 mm, with an 82.4% implant survival rate in nonsmokers compared to 60% in smokers (P < .05). Smoking should be considered as a high risk factor when implants are placed immediately in grafted sinuses, particularly in areas of limited bone height.

The negative effect of combining rhBMP-2 and Bio-Oss on bone formation for maxillary sinus augmentation

Sinus augmentation with various bone graft materials may be required in the posterior maxilla. This study compared bone formation in a lateral window sinus augmentation with recombinant human bone morphogenetic protein 2/acellular collagen sponge (rhBMP-2/ACS) combined with Bio-Oss or Bio-Oss graft alone. Patients were assigned to treatment with either rhBMP-2/ACS + Bio-Oss or Bio-Oss alone. After a healing period, bone cores were harvested. Histologic specimens demonstrated that new bone formation was less in those who received rhBMP-2/ACS + Bio-Oss than those with Bio-Oss alone. This study indicated that the addition of rhBMP-2/ACS to Bio-Oss has a negative effect on bone formation.

Human histologic evaluation of the use of the dental putty for bone formation in the maxillary sinus: case series

A proof-of-principle study was conducted to assess the safety and efficacy of dental putty as an alternative sinus augmentation biomaterial. Six healthy patients requiring a total of 10 sinus augmentations received sinus augmentations. All patients volunteered and signed an informed consent based on the Helsinki declaration of 1975, as revised in 2000. The sinus augmentation was performed under local anesthesia with a mucoperiosteal flap elevated to expose the buccal wall of the maxillary sinus. The space was then filled with the dental putty in several increments, and the window was covered with an absorbable collagen membrane. Biopsies were harvested from all 10 treated sinuses using a 3-mm trephine bur at the time of implant placement at either 6 or at 9 months after sinus augmentation. All patients completed the study without complications, except for 1 patient who reported fistulas at 1 and 2 months after the surgery. Clinical reentry revealed that regenerated bone on the osteotomy site was soft and immature. The ground sections of the biopsied cores revealed minimum amounts of trabeculation surrounded by an abundant array of irregular-shaped residual alloplastic particles embedded in loose connective tissue. The present study's findings revealed inadequate bone formation, although the material appears to be bioinert as there is no elicitation of inflammatory response.

An interarch alveolar ridge relationship classification

Alveolar ridge defects resulting from tooth loss, trauma, periodontal disease, or congenital lesions often require correction prior to dental implant therapy. Numerous classifications proposed to describe alveolar ridge defects have been limited to describe intra-arch relationships. To provide sufficient jaw-to-jaw alveolar ridge (interarch) relationship information for both restorative and surgical treatment decision-making, this article introduces a new interarch alveolar ridge relationship classification system. This article also discusses cone beam computed tomography and multidisciplinary treatment planning options for approaching each classification.

Five-year results of fixed implant-supported rehabilitations with distal cantilevers for the edentulous mandible

OBJECTIVES

The purpose of this study was to evaluate the survival rate, success rate and primary complications associated with mandibular fixed implant-supported rehabilitations with distal cantilevers over 5 years of function.

MATERIAL AND METHODS

In this prospective multi-center trial, 45 fully edentulous patients were treated with implant-supported mandibular hybrid prostheses with distal extension cantilevers. Data were collected at numerous time points, including but not limited to: implant placement, abutment placement, final prosthesis delivery, 3 months and 5 years post-loading. Biological, implant and prosthetic parameters defining survival and success were evaluated for each implant including: sulcus bleeding ndex (SBI) at four sites per implant, width of facial and lingual keratinized gingiva (mm), peri-implant mucosal level (mid-facial from the top of the implant collar, measured in mm), modified plaque index (MPI) at four sites per implant, mobility and peri-implant radiolucency. Survival was defined as implants or prostheses that did not need to be replaced. Success rate was defined as meeting well-established criteria that were chosen to indicate healthy peri-implant mucosa osseointegration, prostheses success and complications.

RESULTS

A total of 237 implants in 45 completely edentulous patients were included in the study. In each patient, four to six implants were placed to support hybrid prostheses with distal cantilevers. Cantilevers ranged in length from 6 to 21 mm, with an average length of 15.6 mm. The ages of the patients ranged from 34 to 78 with a mean age of 59.5 years. The survival rate of implants was 100% (237/237) and for prostheses 95.5% (43/45). The overall treatment success rate was calculated as 86.7% (39/45). Of the six patients that have not met the criteria for success, two patients required replacement of the entire prosthesis and four patients presented >four complications events.

CONCLUSION

Fixed implant-supported rehabilitation with distal cantilever resulted in a reliable treatment modality over the 5-year observation period. Although biological parameters of MPI, SBI, keratinized tissue and peri-implant mucosal levels showed statistically significant differences over time, the mean values for each patient remained within the normal limits of oral health. Complications were categorized as biological or technical. The majority of complications were technical complications (54/79) and of these most involved fracture of the acrylic teeth and base (20/54). While the survival rate was 100% for implants and 95.5% for prostheses, the application of strict criteria for treatment success resulted in an overall treatment success rate of 86.7%.

Osseointegration of titanium implants following guided bone regeneration using expanded polytetrafluoroethylene membrane and various bone fillers

The purpose of this study was to evaluate the percentage of bone-to-implant contact following guided bone regeneration using expanded polytetrafluoroethylene (e-PTFE) membranes and various bone fillers in a beagle dog model. A staged approach was used for initial bone regeneration of surgically created defects and subsequent implant placement in newly regenerated ridges. Three months after bilateral extraction of the mandibular premolars and first molars, rectangular, distal-extension defects that included the entire width of the ridge buccolingually were surgically created in the alveolar processes. All defects were covered with an e-PTFE membrane, and several bone fillers were placed, in a randomized fashion, under the membrane: autogenous bone, demineralized freeze-dried bone, anorganic bovine bone, tricalcium phosphate granules, and collagen sponge. One site in each animal was treated with e-PTFE barrier membrane alone as control. Following an 8-month healing period, nonsubmerged titanium implants (36 total) were placed in regenerated bone following membrane removal. Three months later, the animals were sacrificed, and nondecalcified buccolingual sections were evaluated histometrically for bone-to-implant contact. All sites demonstrated high percentages (50% to 65%) of bone-to-implant contact, with no significant differences across the various treatment groups. In addition, all tested bone fillers formed a complex that supported and maintained the osseointegrated implants in a healthy state, with no apparent signs of peri-implantitis. Using a staged approach, the present study provided histologic and histometric evidence that implants placed in entirely regenerated bone can achieve and maintain osseointegration, regardless of the type of bone fillers used.

Regeneration of standardized mandibular bone defects using expanded polytetrafluoroethylene membrane and various bone fillers

The purpose of this study was to evaluate the new bone formation and biodegradability of various bone fillers placed underneath a nonresorbable membrane (expanded polytetrafluoroethylene [e-PTFE]) in standardized defects in a beagle dog model. Mandibular premolars and first molars were extracted bilaterally in six adult female beagle dogs. Three months after the extractions, six rectangular defects (4 mm apicocoronally, 7 mm mesiodistally, and the entire width of the ridge buccolingually) were surgically created in the alveolar processes. All defects were covered with an e-PTFE membrane and stabilized buccally with stainless steel fixation screws. Five different bone fillers were placed under the membranes in a random configuration in each dog: autogenous bone, demineralized freeze-dried bone, anorganic bovine bone, tricalcium phosphate granules, and collagen sponge. One site in each animal was treated with the e-PTFE membrane alone. Following an 8-month healing period, a bone core was harvested from each grafted site using a trephine drill. Samples from each of the grafted sites were evaluated histologically and histometrically for their bone regenerative potential. The result of this study demonstrated a positive effect of bone fillers on bone regeneration when combined with a nonresorbable membrane; however, no significant differences were found between the various bone fillers in terms of their regenerative potential.

The gene expression profile in refractory periodontitis patients

BACKGROUND

There are no specific bacterial profiles or diagnostic tests capable of identifying refractory periodontitis patients before a treatment regimen is initiated. Therefore, in this high-risk cohort of patients who do not respond appropriately, host factors that might be partly under genetic control may play a crucial role in their susceptibility. Specifically, we tested the hypothesis that patients with refractory periodontitis have multiple upregulated and/or downregulated genes that might be important in influencing clinical risk.

METHODS

Oral subepithelial connective tissues were harvested aseptically from seven refractory periodontitis and seven periodontally well-maintained patients. An RNA isolation kit was used to isolate total RNA from tissue samples that had been stabilized in the RNA stabilizing reagent. The isolated total RNA was then subjected to gene expression profiling using the microarray to measure gene expression levels. The retrieved data were analyzed with a computer program for the differential analysis of gene expression microarray experiments. In addition, real-time polymerase chain reaction (PCR) analysis was performed on selected samples to confirm the microarray data's gene expression patterns.

RESULTS

A total of 68 upregulated and six downregulated genes were identified that were differentially expressed at least two-fold out of 22,283 genes we analyzed. The selected model provided a 93% intrinsic validation along with a 93% extrinsic validation. To validate the microarray data, five upregulated genes (lactotransferrin [LTF], matrix metalloproteinase-1 [MMP-1], MMP-3, interferon induced-15 [IFI-15], and Homo sapiens hypothetical protein MGC5566) and two downregulated genes (keratin 2A [KRT2A] and desmocollin-1 [DSC-1]) were randomly selected for further analysis by real-time PCR. The relative RNA expression level of these genes measured by real-time PCR was similar to those measured by microarrays.

CONCLUSION

The combined use of microarray technology with the computer program for the differential analysis of gene expression microarray experiments provided a set of candidate genes that may serve as novel therapeutic intervention points and improved diagnostic and screening procedures for high-risk individuals.

Peri-implant soft-tissue health surrounding cement- and screw-retained implant restorations: a multi-center, 3-year prospective study

OBJECTIVE

The purpose of this prospective clinical study was to evaluate peri-implant soft-tissue conditions and esthetic fulfillment during a 3-year follow-up period following prosthetic rehabilitation.

MATERIAL AND METHODS

As part of a prospective multi-center study, 152 ITI dental implants were placed in 80 patients in the maxillary anterior region. Fifty-nine crowns (38.82%) were cement retained, while 93 (61.18%) crowns were screw retained. At loading and 3, 6, 12 and 36 months post-loading, modified plaque index (MPI), sulcus bleeding index (SBI), keratinized mucosa (KM), gingival level (GL), and esthetic fulfillment were recorded.

RESULTS

All patients completed the study and no complications were reported. While statistically not significant at all time points, cement-retained crowns seemed to present a worsening trend in MPI and SBI scores. Interestingly, screw-retained crowns seemed to present an opposite picture, their MPI and SBI scores improved over time. While plaque accumulation, prophylaxis and depth of crown margin significantly affected levels of sulcus bleeding, prophylaxis alone played a key role in reducing plaque accumulation. No soft tissue recession was observed in either cement- or screw-retained crowns up to 3 years post-loading. Esthetic fulfillment survey revealed that patients did not have a preference for crown types; however, dentists favored cement-retained over screw-retained crowns.

CONCLUSIONS

Peri-implant soft tissues responded more favorably to screw-retained crowns when compared with cement-retained crowns. However, no soft-tissue recession was observed in either type of crowns. Cement-retained crowns were preferred by dentists, while patients were equally satisfied with either type of crowns they received.

Osseous response following resective therapy with piezosurgery

A piezoelectric instrument vibrating in the ultrasonic frequency range was investigated for its potential use in periodontal resective therapy. The rate of postoperative wound healing (baseline and 14, 28, and 56 days after surgery) in a dog model following surgical ostectomy and osteoplasty was the marker used to compare the efficacy of this instrument (PS) with a commonly used carbide bur (CB) or a diamond bur (DB). The surgical sites treated by CB or DB lost bone, in comparison to baseline measurements, by the 14th day, while the surgical sites treated by PS revealed a gain in the bone level. By day 28, the surgical sites treated by all three instruments demonstrated an increased bone level and regeneration of cementum and periodontal ligament. However, by day 56, the surgical sites treated by CB or DB evidenced a loss of bone, versus a bone gain in the PS-treated sites. Thus, it appears that PS provided more favorable osseous repair and remodeling than CB or DB when surgical ostectomy and osteoplasty procedures were performed. Therefore, PS could be regarded as being efficacious for use in osseous surgery.

Randomized study evaluating recombinant human bone morphogenetic protein-2 for extraction socket augmentation

BACKGROUND

Conventional dentoalveolar osseous reconstruction often involves the use of grafting materials with or without barrier membranes. The purpose of this study was to evaluate the efficacy of bone induction for the placement of dental implants by two concentrations of recombinant human bone morphogenetic protein-2 (rhBMP-2) delivered on a bioabsorbable collagen sponge (ACS) compared to placebo (ACS alone) and no treatment in a human buccal wall defect model following tooth extraction.

METHODS

Eighty patients requiring local alveolar ridge augmentation for buccal wall defects (> or =50% buccal bone loss of the extraction socket) of the maxillary teeth (bicuspids forward) immediately following tooth extraction were enrolled. Two sequential cohorts of 40 patients each were randomized in a double-masked manner to receive 0.75 mg/ml or 1.50 mg/ml rhBMP-2/ACS, placebo (ACS alone), or no treatment in a 2:1:1 ratio. Efficacy was assessed by evaluating the amount of bone induction, the adequacy of the alveolar bone volume to support an endosseous dental implant, and the need for a secondary augmentation.

RESULTS

Assessment of the alveolar bone indicated that patients treated with 1.50 mg/ml rhBMP-2/ACS had significantly greater bone augmentation compared to controls (P < or =0.05). The adequacy of bone for the placement of a dental implant was approximately twice as great in the rhBMP-2/ACS groups compared to no treatment or placebo. In addition, bone density and histology revealed no differences between newly induced and native bone.

CONCLUSION

The data from this randomized, masked, placebo-controlled multicenter clinical study demonstrated that the novel combination of rhBMP-2 and a commonly utilized collagen sponge had a striking effect on de novo osseous formation for the placement of dental implants.

Modulating the Effects of Diabetes on Osseointegration With Aminoguanidine and Doxycycline

BACKGROUND

The current knowledge of wound healing around implant surfaces is quite limited, particularly as it relates to the effects of systemic diseases such as diabetes. The purpose of our research is to histologically evaluate the effects of aminoguanidine and doxycycline in the modification of peri-implant wound healing around endosseous implants in diabetic rats.

METHODS

Thirty-two Sprague-Dawley rats were randomly assigned to four different treatment groups. One group served as the non-diabetic control, while diabetes was induced in other groups. Titanium plasma-sprayed (TPS) implants were placed in the femora of each animal 2 weeks following diabetic induction. One group of diabetic rats was given aminoguanidine via intraperitoneal injection, and another given doxycycline via oral gavage for 28 days beginning on the day of implantation. The third group of diabetic rats received no medication (controls). All animals were sacrificed following 28 days of healing.

RESULTS

The results were measured by marrow bone-to implant contact (MBIC) between the groups. Values for MBIC were greater for the non-diabetic control group than the diabetic control group (P < 0.001). Aminoguanidine-treated diabetic animals had a significantly greater MBIC than the diabetic control group (P < 0.01). Diabetic animals receiving doxycycline did not differ significantly from the diabetic control group (P > 0.05).

CONCLUSIONS

The results of this study using a rat model con- firm previous reports that diabetes inhibits osseointegration, as defined by MBIC. In addition, this study demonstrates that the detrimental effects of diabetes on osseointegration can be modified using aminoguanidine systemically. However, systemic administration of doxycycline only slightly enhances osseointegration.

Maintenance of Osseointegration Utilizing Insulin Therapy in a Diabetic Rat Model

BACKGROUND

Normal wound healing processes have been shown to be altered in diabetes, and the effect of the diabetes on bone-to-implant contact (BIC) once osseointegration has been established is still unknown. The purpose of this study was to histologically evaluate the bone-to-implant contact in uncontrolled and insulin-controlled rats in which diabetes was induced following the establishment of osseointegration.

METHODS

Thirty-two rats were assigned to eight different treatment groups of four each. Titanium plasma-sprayed (TPS) implants were placed in the femora of each animal, and allowed to osseointegrate for 28 days before diabetic induction. Daily insulin injections were given to four groups of rats and the other four groups received no insulin (uncontrolled). The rats were sacrificed at 1, 2, 3, and 4 months following diabetic induction.

RESULTS

The results indicated that at 1, 2, 3, and 4 months, there was more BIC in the insulin-controlled groups compared to the uncontrolled groups. The differences were significantly greater at 2, 3, and 4 months (P < or =0.001).

CONCLUSIONS

This study demonstrated that osseointegrated dental implants in insulin-controlled diabetic rats maintained bone-to-implant contacts over a 4-month period. However, boneto- implant contact appears to decrease with time in uncontrolled diabetic rats.

Measuring the efficacy of rhBMP-2 to regenerate bone: a radiographic study using a commercially available software program

This radiographic study evaluated the efficacy of different concentrations of rhBMP-2 to regenerate bone in alveolar defects in the anterior maxilla. The study was performed using reasonably standardized CT examinations and the Simplant program. The radiographic measurements were further refined by careful standardization of the measured regions of interest. There was a statistically significant difference in bone formation between subjects treated with a concentration of 1.5 mg/mL rhBMP-2 compared with each of the other groups. There was no statistically significant difference in bone volume between any of the other groups. None of the groups showed a loss in bone volume.

Localized Ridge Augmentation/Preservation.A Systematic Review

BACKGROUND

Osseointegrated implants have been documented as efficacious, however, their placement may be contraindicated in some patients due to insufficient bone volume. Techniques such as guided bone regeneration (GBR), immediate implantation, and distraction osteogenesis (DO) have been utilized as ridge enhancement therapies.

RATIONALE

This systematic review evaluates dental implant survival rates in patients treated with ridge augmentation or preservation techniques.

FOCUSED QUESTION

In patients requiring dental implant placement, what is the effect of localized ridge preservation versus implant placement without augmentation on implant survival and adverse effects?

SEARCH PROTOCOL

MEDLINE and Cochrane Oral Health Group Specialized Trial Register were searched. Hand searches were performed on Clinical Oral Implants Research, International Journal of Oral and Maxillofacial Implants, International Journal of Periodontics and Restorative Dentistry, Journal of Clinical Periodontology, Journal of Periodontology, and Journal of Periodontal Research. All searches were performed for articles published through April 2002.

SELECTION CRITERIA

Publications reporting survival rate of dental implants following ridge therapy were included in the analysis. Reports describing techniques were excluded.

DATA COLLECTION AND ANALYSIS

Due to the absence of controlled studies, a meta-analysis was not performed. Descriptive statistics are used to report the data.

MAIN RESULTS

1. A total of 18 studies were included: 13 reporting on guided bone regeneration (GBR, 1,741 patients) and 5 on distraction osteogenesis (DO, 92 patients). 2. There is a high level of predictable implant survival in sites treated by GBR or DO. 3. These survival rates are similar to those of implants placed in native bone. REVIEWERS' INTERPRETATIONS: Survival rates were similar for both GBR and DO implants. These survival rates were similar to implants placed in native bone.

Membrane type (MT) 1-matrix metalloproteinase (MMP) and MMP-2 expression in ligature-induced periodontitis in the rat

BACKGROUND

Matrix metalloproteinases (MMPs) have been shown to be involved in the degradation of the extracellular matrix (ECM). In particular, MMP-2 and MMP-9 (gelatinase A and gelatinase B, respectively) have been identified as the predominant MMPs during periodontitis. Recent studies have indicated that a novel transmembrane MMP, mebrane-type 1 matrix metalloproteinase (MT1-MMP), can activate pro-MMP-2 in tumor metastasis. This study aims to elucidate the presence and localization of MT1-MMP and MMP-2 in periodontitis in a rat model.

METHODS

In 2 groups of 40-day-old male Sprague-Dawley rats, periodontitis was initiated by ligating floss around maxillary second molars. A group of control animals were left untreated. Maxillary dentoalveolar segments were isolated after 7 and 21 days postinduction and were prepared for gross and radiographic analysis of bone loss and for histological analysis. Samples were also prepared for gel zymography to detect the presence of MMP-2, and for Northern blot analysis and in situ hybridization with MT1-MMP probes.

RESULTS

MMP-2 expression increased at 21 days following ligature placement, in conjunction with MT1-MMP expression. MT1-MMP mRNA expression was observed in epithelial cells, fibroblasts, and in multinucleated cells in the periodontium.

CONCLUSION

Our data suggest that MT1-MMP may play a role in extracellular matrix degradation during periodontitis, in concert with MMP-2 and other proteinases.

Treatment of periodontitis by local administration of minocycline microspheres: a controlled trial

BACKGROUND

Periodontitis is an inflammatory condition of tooth-supporting tissues that is usually treated by mechanical removal of plaque and microorganisms that adhere to teeth. This treatment, known as scaling and root planing, is not optimally effective. Adjunctive therapy with locally delivered antimicrobials has resulted in improved clinical outcomes such as probing depth reduction. This article reports on the efficacy and safety of locally administered microencapsulated minocycline.

METHODS

Seven hundred forty-eight (748) patients with moderate to advanced periodontitis were enrolled in a multi-center trial and randomized to 1 of 3 treatment arms: 1) scaling and root planing (SRP) alone; 2) SRP plus vehicle; or 3) SRP plus minocycline microspheres. The primary outcome measure was probing depth reduction at 9 months. Clinical assessments were performed at baseline and 1, 3, 6, and 9 months.

RESULTS

Minocycline microspheres plus scaling and root planing provided substantially more probing depth reduction than either SRP alone or SRP plus vehicle. The difference reached statistical significance after the first month and was maintained throughout the trial. The improved outcome was observed to be independent of patients' smoking status, age, gender, or baseline disease level. There was no difference in the incidence of adverse effects among treatment groups.

CONCLUSIONS

Scaling and root planing plus minocycline microspheres is more effective than scaling and root planing alone in reducing probing depths in periodontitis patients.

A 5-year prospective clinical and radiographic study of non-submerged dental implants

Osseointegrated implants as anchors for various prosthetic reconstructions have become a predictable treatment alternative. It was expected that implants required submucosal placement during the healing period for successful tissue integration. However, it has been demonstrated that healing and long-term health of implants could be achieved with equal predictability in a 1-stage, non-submerged approach. This prospective 5-year study not only calculates implant success by life table analysis, but also evaluates the correlation between observed bone level changes with clinical parameters as measured by suppuration, plaque indices, bleeding indices, probing depth, attachment level and mobility. A total of 112 ITI dental implants were inserted in different areas of the jaws. Clinical and radiographic parameters were evaluated annually for 5 years, whereas a portion of the study group for which 6-year evaluations were available were included in the life-table analysis. The overall success rate after 5 years in service was 99.1%, while after 6 years it was reduced to 95.5% due to the fracture of 3 implants in 1 patient. The mean crestal bone loss experienced during the first year was 0.6 mm followed by an annual yearly loss of approximately 0.05 mm. No significant differences could be found between the amount of bone loss measured at each of the yearly follow-up visits. This suggests that statistically the followed implants did not show any radiographically measurable bone loss following the initial period of bone loss associated with implant placement and osseointegration. Low levels of correlation between the individual and cumulative clinical parameters with radiographically measured bone loss suggests that these parameters are of limited clinical value in assessing and predicting future peri-implant bone loss.

Effect on bone healing of bone morphogenetic protein placed in combination with endosseous implants: a pilot study in beagle dogs

Although dental implants have become an effective treatment modality for the replacement of missing teeth, their predictability relies on successful osseointegration during the healing period. The purpose of this pilot study was to evaluate the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) on early bone formation within the perforations of dental implants in beagle dogs. Histologic sections were evaluated for the extent of new bone formation within a 1-mm diameter of through-and-through perforations. Data indicated that significantly more bone formation occurred with rhBMP-2-treated sites within the implant perforation (P < 0.01) compared to sites treated with the vehicle alone. This pilot study indicates that rhBMP-2 increases the rate and extent of bone formation in combination with dental implants.

Relationship between crevicular aspartate aminotransferase levels and periodontal disease progression

BACKGROUND

Aspartate aminotransferase (AST), an enzyme released from necrotic cells, has been identified in gingival crevicular fluid (GCF), and elevated levels are associated with periodontal tissue destruction. The aim of this study was to examine the relationship between elevated GCF levels of AST and periodontal disease progression.

METHODS

Over a 12-month period, 8 to 10 interproximal sites in 41 periodontitis subjects (PS) and 15 healthy subjects (HS) were monitored. Clinical measurements included relative attachment level (RAL), probing depth, and bleeding on probing (BOP). Semiquantitative levels of GCF AST (< 800 microIU, > or = 800 microIU, and > or = 1,200 microIU) were determined using a chairside assay. At the 6- and 12-month visits, scaling and root planing and prophylaxis were performed in the PS and HS, respectively. Sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV) were calculated for 2 diagnostic criteria (AST > or = 800 microIU, AST > or = 1,200 microIU) utilizing 4 thresholds of disease progression as determined by 2 methods (absolute change in relative attachment level and cumulative sum [CUSUM]).

RESULTS

The percentage of sites exhibiting AST > or = 800 microIU, AST > or = 1,200 microIU, and BOP in the PS was significantly (P<0.02) lower at 6 and 12 months compared to baseline. The use of crevicular AST activity to monitor periodontal disease progression was associated with many false-positive results. Overall, low specificities, PPV, and odds ratios were demonstrated by the assay when using 2 diagnostic criteria and 4 thresholds of disease progression. The high NPV suggest that a negative AST test result was indicative of a periodontally stable site.

CONCLUSIONS

These results demonstrate that elevated levels of AST were present at sites that did not subsequently exhibit disease progression. The high prevalence of AST-positive sites due to gingival inflammation diminished the test's ability to discriminate between progressive and stable, but inflamed, sites.

Benchmarking the dental implant evidence on MEDLINE

The purpose of this study was to estimate the quantity of dental implant literature available on MEDLINE for evidence-based clinical decision-making and to identify its location. A search strategy based on Medical Subject Headings for dental implants was developed to examine MEDLINE using the Ovid Web Gateway search engine. Sensitive and specific methodologic search filters identified 4 categories of information: etiology, diagnosis, therapy, and prognosis. The results were then subdivided by year to identify trends and sorted to identify the sources of publications. The searches identified 4,655 articles published in English between 1989 and 1999 on human dental implants on MEDLINE. The mean number of articles (+/- SD) per year ranged from 15 +/- 11 for specific searches to 107 +/- 50 for sensitive searches. The number of articles increased by 14% to 43% each year for the sensitive search. When subdivided by clinical category, the mean numbers of articles per year for sensitive and specific searches were, respectively: diagnosis 12 +/- 7.5 and 1.5 +/- 1.6, etiology 58 +/- 33 and 1.9 +/- 2.5, therapy 23 +/- 15 and 0.3 +/- 0.5, and prognosis 67 +/- 33 and 12 +/- 8.3. Four dental journals account for approximately half of these publications. These results provide 6 key central findings: (1) there appears to be a substantial literature of clinically relevant information on implants upon which to base clinical decisions; (2) the implant literature is significantly biased toward articles addressing prognosis; (3) to stay current, one would need to read between 1 and 2 articles per week 52 weeks per year, and this number increases significantly each year; (4) approximately 50% of the articles were published in 4 journals, whereas the remainder reside in approximately 97 other journals, making it difficult to stay current; (5) these trends reaffirm the need for lifelong learning; (6) these trends also suggest the need for computer-based clinical knowledge systems.

Human histologic evaluation of bioactive ceramic in the treatment of periodontal osseous defects

This study examined the healing of intrabony defects around 5 teeth treated with bioactive glass ceramic (PerioGlas). Healing was evaluated by clinical measurements, radiographic observation, and histologic analysis. The protocol included a presurgical phase of scaling and root planing therapy, with measurements obtained immediately prior to the surgical procedures and after 6 months of healing. Following therapy there was a mean of 2.7 mm of probing depth reduction, 2.2 mm of clinical attachment gain, and 0.5 mm of recession. The histologic analysis revealed healing by a long junctional epithelium with minimal new connective tissue attachment to the teeth, except in one case where the intrabony region demonstrated new cementum formation and new connective tissue attachment. Graft particles were found to be biocompatible, as evidenced by being embedded in a stroma of dense connective tissue with minimal inflammatory infiltrate. There was minimal new bone formation limited to the most apical borders of the defects. No signs of periodontal regeneration as defined by new cementum, periodontal ligament, and bone formation on a previously diseased root surface were observed. Although the clinical results are encouraging and radiographs evidenced radiopacities within the defects, histologic analysis revealed that as a periodontal grafting material, bioactive glass ceramic has only limited regenerative properties.

A retrospective study of dental implants in diabetic patients

The efficacious placement of dental implants in diabetic patients remains controversial. Definitive guidelines with objective criteria, including the type of diabetes, age of onset, and level of long-term control, have not been determined. In addition, few relevant literature citations assess the survival rate of implants in diabetic patients. Therefore, it is the purpose of this study to assess the success and survival rates of dental implants in diabetic patients. In this retrospective analysis, 215 implants placed in 40 patients at 2 clinical centers were evaluated. Chart reviews and interviews provided medical and implant data. From the analysis, 31 failures occurred, for an overall success rate of 85.6%. Of these failures, 24 occurred within the first year of functional loading. The mean time of functional load was 4.05 +/- 2.6 years. When the success rate was analyzed by implant location, success rates for the maxilla and mandible were 85.5% and 85.7%, respectively. For the anterior and posterior regions, success rates were 83.5% and 85.6%, respectively. The lifetable analysis revealed a cumulative success rate of 85.7% after 6.5 years of function. Based on the data, the survival rate of dental implants in controlled diabetic patients is lower than that documented for the general population, but there is still a reasonable success rate. The increase in failure rate occurs during the first year following prosthetic loading.

Evaluation of recombinant human bone morphogenetic protein-2 in oral applications including the use of endosseous implants: 3-year results of a pilot study in humans

BACKGROUND

This study evaluated patients who had been treated with recombinant human bone morphogenetic protein-2 (rhBMP-2) loaded in an absorbable collagen sponge (ACS) in human extraction sites or in sites that required alveolar ridge augmentation. An earlier report on the same patients revealed that after 4 months, implantation of rhBMP-2/ACS was safe, as determined by clinical, radiographic, systemic, and immunological analyses. In this longer-term follow-up, eligible patients were restored with endosseous dental implants in the area treated with rhBMP-2/ACS and bone biopsy samples were taken for histological analysis of the treated human bone tissue. The primary objective was to monitor the long-term safety of patients treated with rhBMP-2/ACS. Another objective was to evaluate the dental implants placed in the sites treated with rhBMP-2.

METHODS

Patient safety was evaluated by clinical examinations, periapical radiographs, and occurrence of adverse experiences. Dental implants were evaluated by radiographic and clinical examination. All 12 patients have been followed for 3 years.

RESULTS

Two years following surgical implantation of rhBMP-2/ACS, no serious or unexpected adverse experiences occurred. The adverse experiences that did occur were mostly benign and compatible with the dental implant surgeries performed in these patients. No adverse experiences were deemed as related to the rhBMP-2/ACS. Furthermore, no safety concerns in the local area of rhBMP-2/ACS placement were noted, based on oral wound examinations. In the 10 patients (6 extraction socket patients and 4 augmentation patients) who received endosseous implants, all implants were clinically stable at all assessments and all 10 patients have been functionally restored. Histological evaluation of the human bone core biopsies revealed normal bone tissue formation identical to the surrounding native bone. Three-year follow-up clinical examinations revealed that all implants had stable marginal bone levels and healthy peri-implant tissues.

CONCLUSIONS

These 3-year results demonstrate that rhBMP-2/ACS can be used safely in human patients. Human bone biopsies reveal normal bone formation in areas treated with rhBMP-2/ACS. Endosseous implants placed in these areas were all stable with no radiographic or clinical complications. The results from this study suggest that rhBMP-2/ACS (0.43 mg/ml) can be safely used in tooth extraction sites and in local ridge augmentation procedures and that endosseous dental implants placed in bony areas treated with rhBMP-2/ACS are stable and can be functionally restored without complication.