Publications by authors named "Guy Huynh-Ba"

46 Publications

Impact of different surgical protocols on dimensional changes of free soft tissue autografts: A randomized controlled trial.

J Periodontol 2021 Jan 16;92(1):45-53. Epub 2020 Oct 16.

Department of Periodontics, UT Health San Antonio School of Dentistry, San Antonio, TX.

Background: To determine if there is a difference in the amount of shrinkage during healing of free soft tissue autografts (FSTAs) using different surgical techniques-suturing the vestibular flap margin apically to the base of the recipient bed versus leaving the flap margin free and unsutured.

Methods: Twenty-eight patients with mucogingival defects requiring FSTAs were recruited and enrolled in the study. Patients were randomized into test and control groups (14 per group) and received ≥1 FSTAs on non-molar mandibular teeth. In the test group the mucosal flap margin was sutured apically to the periosteum at the base of the graft; whereas, the mucosal flap margin in the control group was left free. Graft dimensional measurements were taken at time of surgery, then at 1, 3, and 6 months post-surgery.

Results: Thirty-five grafts were performed (15 test, 20 control). All FSTAs experienced vertical shrinkage after 6 months, but there was no significant difference (P = 0.51) in the mean amount of shrinkage after 6 months between the test (23.20% ± 20.88%) and control (21.10% ± 21.88%) groups. There was significantly greater horizontal shrinkage in the test (loss of 7.59% ± 10.20%) compared with the control (small gain of 0.32% ± 4.20%) group (P = 0.01).

Conclusions: The findings suggest that there is similar vertical shrinkage when performing FSTA surgery when the mucosal flap margin is left free and unsutured when compared with leaving the flap margin free.
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http://dx.doi.org/10.1002/JPER.20-0033DOI Listing
January 2021

Management of Thick and Thin Periodontal Phenotypes for Immediate Dental Implants in the Esthetic Zone: A Controlled Clinical Trial.

Int J Periodontics Restorative Dent 2020 Jan/Feb;40(1):51-59

The goal of the study was to compare the outcome of immediate single-implant placement in esthetic sites of patients with thick or thin tissue phenotypes. Forty-one patients underwent implant surgery with guided bone regeneration including peri-implant gap and overcontour grafting. A connective tissue graft was added only for patients with a thin tissue phenotype. Twenty-six patients completed the 12-month follow-up examination (thick, n = 14; thin, n = 12). The thick-phenotype group gained 0.01 ± 1.56 mm of midfacial soft tissue height, while the thin-phenotype group lost 0.20 ± 1.14 mm (P = .21). There was no significant difference in buccal plate thickness achieved at time of uncovery, pink and white esthetic scores, radiographic bone levels, and clinical parameters between the two groups. These results suggest that when the suggested treatment protocol is followed, there are no significant differences in the outcomes of immediate implant placement for patients with different soft tissue phenotypes.
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http://dx.doi.org/10.11607/prd.4317DOI Listing
December 2019

Change in Crown-to-Implant Ratio of Implants Placed in Grafted and Nongrafted Posterior Maxillary Sites: A 5-year Prospective Randomized Study.

Int J Oral Maxillofac Implants 2019 Sep/Oct;34(5):1231-1236

Purpose: The aim of this study was to evaluate the performance of implants placed for 5 years in grafted vs nongrafted sinuses in relation to crown-to-implant ratio. The measurements of crown and implant lengths took into account changes in both endo-sinus and crestal bone levels over 5 years.

Materials And Methods: Enrolled patients required one or two implants in at least one sinus and presented a residual bone height of posterior maxilla ≤ 4 mm. Individual sinuses were randomly allocated either to be grafted or not before surgery. Implants of 8 mm in length were placed using osteotome sinus floor elevation (OSFE). After 10 weeks of healing, they were loaded functionally using definitive single crowns. Radiographic measurements were made on periapical radiographs taken at surgery, prosthetic steps, and 5 years. The implant length was measured between the most apical and coronal contact of bone and implant, and the crown length was measured between the most occlusal point of the crown and the crestal bone. Data were analyzed using mixed linear models.

Results: Twenty implants were placed in grafted sinuses and 17 in native bone (12 patients). One of the 35 restored implants failed. Immediately after surgery, the mean lengths of the implants placed in grafted and nongrafted sites were 2.4 ± 0.8 and 2.7 ± 0.9 mm, respectively (P = .351). At loading, the mean crown-to-implant ratios were 3.8 ± 0.8 and 4.6 ± 2.0 (P = .033), respectively, whereas at 5 years, they were 2.0 ± 0.8 and 2.1 ± 0.4, respectively (P = .341).

Conclusion: The use of grafting material is not necessary to restore posterior maxilla ≤ 4 mm with OSFE and simultaneous implant placement. Over 5 years, all restored implants but one were functional. Despite unfavorable conditions in terms of initial bone anchorage and height of single crown restoration, a high initial crown-to-implant ratio did not compromise the long-term survival of implants placed in grafted or nongrafted sinuses.
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http://dx.doi.org/10.11607/jomi.6766DOI Listing
December 2019

Healing at Molar Extraction Sites Using Freeze-Dried Bone Allograft and Collagen Wound Dressing: Case Series and Three-Arm Analyses.

Int J Oral Maxillofac Implants 2019 Sep/Oct;34(5):1202-1212

Purpose: Ridge preservation limits dimensional changes after tooth extraction. However, it is still unclear if using a membrane may be advantageous over a collagen wound dressing. Therefore, the goal of this report was to evaluate the outcomes of ridge preservation using freeze-dried bone allograft with a collagen wound dressing.

Materials And Methods: This study included 21 patients who had one molar extracted, and the site received ridge preservation using freeze-dried bone allograft and a collagen wound dressing (test 2 group). Patients had two standardized cone beam computed tomography (CBCT) scans, taken within 72 hours and 3 months after extraction, to measure changes in ridge height and width, and buccal and lingual plate thicknesses. Changes in keratinized tissue width were recorded. Three-arm analyses were performed using historic data from a previous randomized controlled trial by the same study group, in which 20 molar sites received a collagen wound dressing alone (control) and 20 received ridge preservation with freeze-dried bone allograft and a dense polytetrafluoroethylene membrane (test 1) using the same methodology.

Results: There was a statistically significant difference in mean buccal ridge height changes between the control group (2.6 ± 2.06 mm) and test 2 group (1.55 ± 0.93 mm) but no difference in ridge and keratinized tissue width changes between groups. No correlation was found between buccal plate thickness and ridge width change.

Conclusion: Freeze-dried bone allograft with collagen wound dressing as a barrier was used successfully for ridge preservation in intact molar extraction sites (< 50% bone loss) and can be considered as a treatment alternative to freeze-dried bone allograft with a dense polytetrafluoroethylene membrane.
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http://dx.doi.org/10.11607/jomi.7243DOI Listing
December 2019

Evaluation of healing at molar extraction sites with and without ridge preservation: A three-arm histologic analysis.

J Periodontol 2020 01 11;91(1):74-82. Epub 2019 Aug 11.

Department of Periodontics, UT Health San Antonio, San Antonio, TX.

Background: Little evidence is available regarding the benefit of ridge preservation (RP) at molar sites. The primary objective of this three-arm cohort study was to histologically compare the healing outcome between natural healing after molar tooth extraction and two different techniques of RP using freeze-dried bone allograft (FDBA) and a nonresorbable dense polytetrafluoroethylene (dPTFE) membrane, or an absorbable collagen sponge as a barrier.

Methods: Seventy-nine patients requiring extraction and delayed implant placement were placed into three groups: extraction alone (control); ridge preserved using FDBA; and either dPTFE (Test1) or collagen sponge (Test2). Bone cores were harvested from implant osteotomies at ≈3 months after extraction for histomorphometric analysis to determine the percentage of vital bone, residual graft, and connective or other tissue. Ridge dimension changes were also evaluated radiographically (cone-beam computed tomography).

Results: The percentage of vital bone was significantly greater in control group compared with Test1 but was not statistically different among other groups. Test2 showed significantly less connective or other tissue than control and Test1. The percentage of residual graft was significantly lower in Test1 compared with Test2. There was no significant correlation between the percentage of vital bone or residual graft and the following parameters: healing time, patient age, gender, buccal plate thickness, or radiographic changes in ridge dimensions.

Conclusion: RP at molar sites using FDBA and an absorbable collagen sponge may be a sufficient and economic way to preserve the ridge dimension without interfering with the amount of new bone formation.
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http://dx.doi.org/10.1002/JPER.19-0237DOI Listing
January 2020

Transferring subgingival contours around implants and the intaglio surface of the pontic to definitive digital casts by using an intraoral scanner: A technique.

J Prosthet Dent 2020 Feb 12;123(2):210-214. Epub 2019 Jun 12.

Private practice, Fukuoka, Japan.

The accurate transfer of the subgingival contours of implant-supported restorations and pontics is essential for providing the dental technician with the necessary information to fabricate an optimal definitive fixed dental prosthesis. However, once the interim restoration is removed to make an impression, the subgingival tissue, which is no longer physically supported, tends to collapse. This digital intraoral and extraoral scanning technique offers a way to transfer the subgingival contours and intaglio surface of the interim restoration to the definitive restoration. In addition, this technique can reduce clinical and laboratory time, as well as the necessity of storing gypsum casts.
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http://dx.doi.org/10.1016/j.prosdent.2019.04.008DOI Listing
February 2020

Esthetic, clinical, and radiographic outcomes of two surgical approaches for single implant in the esthetic area: 1-year results of a randomized controlled trial with parallel design.

Clin Oral Implants Res 2019 Aug 7;30(8):745-759. Epub 2019 Jun 7.

Department of Periodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas.

Aim: The objectives of this study were to compare (a) esthetic, (b) clinical, (c) radiographic, and (d) patient-centered outcomes following immediate (Type 1) and early implant placement (Type 2).

Material And Methods: Forty-six subjects needing a single extraction (premolar to premolar) were randomly allocated to Type 1 or Type 2 implant placement. One year following permanent restoration, evaluation of (a) Esthetics using soft tissue positions, and the pink and white esthetic scores (PES/WES), (b) Clinical performance using probing depth, modified plaque index, and sulcus bleeding index (c) Radiographic bone level, and (d) Patient satisfaction by means of visual analogue scales (VAS) was recorded.

Results: Thirty-five patients completed the one-year examination (Type 1, n = 20; Type 2, n = 15). Type 1 implants lost 1.03 ± 0.24 mm (mean ± SE) of mid-facial soft tissue height while Type 2 implants lost 1.37 ± 0.28 mm (p = 0.17). The papillae height on the mesial and distal was reduced about 1 mm following both procedures. Frequency of clinical acceptability as defined by PES ≥ 6 (Type 1: 55% vs. Type 2 40%), WES ≥ 6 (Type 1: 45% vs. Type 2 27%) was not significantly different between groups (p > 0.05). Clinical and radiographic were indicative of peri-implant health. Patient-centered outcomes failed to demonstrate significant differences between the two cohorts.

Conclusion: One year after final restoration, there were no significant differences in esthetic, clinical, radiographic, and patient-centered outcomes following Type 1 and Type 2 implant placement. At one year, patient satisfaction may be achieved irrespective of the two placement protocols.
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http://dx.doi.org/10.1111/clr.13458DOI Listing
August 2019

A Randomized, Controlled, Multicenter Clinical Study Evaluating The Crestal Bone Level Change Of SLActive Bone Level Ø 3.3 mm Implants Compared To SLActive Bone Level Ø 4.1 mm Implants For Single-Tooth Replacement.

Int J Oral Maxillofac Implants 2019 May/June;34(3):708–718. Epub 2019 Apr 1.

Purpose: The purpose of this prospective randomized clinical trial was to test the hypothesis that narrow-diameter titanium-zirconium (Ti-Zr) alloy implants with a chemically modified hydrophilic surface are not inferior in regard to crestal bone level change compared with standard-diameter implants with the same implant surface and material (control).

Materials And Methods: This multicenter study included 50 patients in need of a single tooth replacement in the anterior (canine to canine) or premolar region of the mandible or maxilla. Patients were included if the site could accommodate a 4.1-mm-diameter implant. Implants were temporarily restored at 3 to 4 weeks after placement. Definitive restorations were delivered 4 to 6 months after placement. Patients returned 1 year after implant loading for clinical measurements and radiographic examination. The primary outcome was mean crestal bone level changes measured between implant loading and 12 months postloading. Secondary outcomes included implant success, survival, gingival recession, and patient satisfaction.

Results: Fifty patients were enrolled; 47 completed the study. Twenty-three patients were in the narrow-diameter implant group (test), and 24 patients were in the standard-diameter implant group (control). The success and survival rates at 12 months postloading were 100% for both groups. The change in the mean crestal bone level from implant loading to 12 months postloading around narrow-diameter implants was -0.27 ± 0.34 mm. For the standard-diameter implants, the change was significantly higher at -0.48 ± 0.67 mm (P = .02). No significant difference was found in gingival recession and patient satisfaction.

Conclusion: The results of this prospective randomized clinical trial suggest noninferiority of the narrow- vs standard-diameter Ti-Zr implant. In addition, bone remodeling was less pronounced for the narrow-diameter implants.
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http://dx.doi.org/10.11607/jomi.6927DOI Listing
August 2019

Immediate loading vs. early/conventional loading of immediately placed implants in partially edentulous patients from the patients' perspective: A systematic review.

Clin Oral Implants Res 2018 Oct;29 Suppl 16:255-269

Health Sciences & Human Services Library, University of Maryland, Baltimore, Maryland.

Objectives: This systematic review aimed at answering the following PICO question: In patients receiving immediate (Type 1) implant placement, how does immediate compare to early or conventional loading in terms of Patient-Reported Outcome Measures (PROMs)?

Material And Methods: Following search strategy development, the OVID, PubMed, EMBASE, and Cochrane Database of Systematic Reviews databases were search for the relevant literature. All levels of evidence including randomized controlled trials, prospective and retrospective cohort studies, and case series of at least five patients were considered for possible inclusion. An additional manual search was performed by screening the reference lists of relevant studies and systematic reviews published up to May 2017. The intervention considered was the placement of immediate implant. Study selection and data extraction were performed independently by two reviewers.

Results: The search yielded a list of 1,102 references, of which nine were included in this systematic review. The limited number of studies included and the heterogeneity of the data identified prevented the performance of a meta-analysis. Three studies, one of which was a randomized controlled trial, allowed the extraction of comparative data specific to the aim of the present systematic review. The remaining studies allowed only data extraction for one single treatment modality and were viewed as single cohort studies. Overall, irrespective of the PROMs chosen, patients' satisfaction was overall high with little difference between the two loading protocols. Moreover, studies indicated a positive impact on oral health-related quality of life following immediate implant placement and loading.

Conclusions: Within the limitations of the present systematic review, immediate implant placement and loading in single tooth edentulous space seems to be a well-accepted treatment modality from the patients' perspective and is worthy of consideration in clinical practice. However, the paucity of comparative data limits any definitive conclusions as to which loading protocol; immediate or early/conventional, should be given preference based on PROMs.
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http://dx.doi.org/10.1111/clr.13278DOI Listing
October 2018

Group 3 ITI Consensus Report: Patient-reported outcome measures associated with implant dentistry.

Clin Oral Implants Res 2018 Oct;29 Suppl 16:270-275

Universidad Inter Continental, Mexico City, Mexico.

Objectives: The aim of Working Group 3 was to focus on three topics that were assessed using patient-reported outcome measures (PROMs). These topics included the following: (a) the aesthetics of tooth and implant-supported fixed dental prostheses focusing on partially edentulous patients, (b) a comparison of fixed and removable implant-retained prostheses for edentulous populations, and (c) immediate versus early/conventional loading of immediately placed implants in partially edentate patients. PROMs include ratings of satisfaction and oral health-related quality of life (QHRQoL), as well as other indicators, that is, pain, general health-related quality of life (e.g., SF-36).

Materials And Methods: The Consensus Conference Group 3 participants discussed the findings of the three systematic review manuscripts. Following comprehensive discussions, participants developed consensus statements and recommendations that were then discussed in larger plenary sessions. Following this, any necessary modifications were made and approved.

Results: Patients were very satisfied with the aesthetics of implant-supported fixed dental prostheses and the surrounding mucosa. Implant neck design, restorative material, or use of a provisional restoration did not influence patients' ratings. Edentulous patients highly rate both removable and fixed implant-supported prostheses. However, they rate their ability to maintain their oral hygiene significantly higher with the removable prosthesis. Both immediate provisionalization and conventional loading receive positive patient-reported outcomes.

Conclusions: Patient-reported outcome measures should be gathered in every clinical study in which the outcomes of oral rehabilitation with dental implants are investigated. PROMs, such as patients' satisfaction and QHRQoL, should supplement other clinical parameters in our clinical definition of success.
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http://dx.doi.org/10.1111/clr.13299DOI Listing
October 2018

Peri-implant diseases and conditions: Consensus report of workgroup 4 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

J Periodontol 2018 06;89 Suppl 1:S313-S318

Department of Reconstructive Dentistry, University of Basel, Basel, Switzerland.

A classification for peri-implant diseases and conditions was presented. Focused questions on the characteristics of peri-implant health, peri-implant mucositis, peri-implantitis, and soft- and hard-tissue deficiencies were addressed. Peri-implant health is characterized by the absence of erythema, bleeding on probing, swelling, and suppuration. It is not possible to define a range of probing depths compatible with health; Peri-implant health can exist around implants with reduced bone support. The main clinical characteristic of peri-implant mucositis is bleeding on gentle probing. Erythema, swelling, and/or suppuration may also be present. An increase in probing depth is often observed in the presence of peri-implant mucositis due to swelling or decrease in probing resistance. There is strong evidence from animal and human experimental studies that plaque is the etiological factor for peri-implant mucositis. Peri-implantitis is a plaque-associated pathological condition occurring in tissues around dental implants, characterized by inflammation in the peri-implant mucosa and subsequent progressive loss of supporting bone. Peri-implantitis sites exhibit clinical signs of inflammation, bleeding on probing, and/or suppuration, increased probing depths and/or recession of the mucosal margin in addition to radiographic bone loss. The evidence is equivocal regarding the effect of keratinized mucosa on the long-term health of the peri-implant tissue. It appears, however, that keratinized mucosa may have advantages regarding patient comfort and ease of plaque removal. Case definitions in day-to-day clinical practice and in epidemiological or disease-surveillance studies for peri-implant health, peri-implant mucositis, and peri-implantitis were introduced. The proposed case definitions should be viewed within the context that there is no generic implant and that there are numerous implant designs with different surface characteristics, surgical and loading protocols. It is recommended that the clinician obtain baseline radiographic and probing measurements following the completion of the implant-supported prosthesis.
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http://dx.doi.org/10.1002/JPER.17-0739DOI Listing
June 2018

Peri-implant diseases and conditions: Consensus report of workgroup 4 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

J Clin Periodontol 2018 06;45 Suppl 20:S286-S291

Department of Reconstructive Dentistry, University of Basel, Basel, Switzerland.

A classification for peri-implant diseases and conditions was presented. Focused questions on the characteristics of peri-implant health, peri-implant mucositis, peri-implantitis, and soft- and hard-tissue deficiencies were addressed. Peri-implant health is characterized by the absence of erythema, bleeding on probing, swelling, and suppuration. It is not possible to define a range of probing depths compatible with health; Peri-implant health can exist around implants with reduced bone support. The main clinical characteristic of peri-implant mucositis is bleeding on gentle probing. Erythema, swelling, and/or suppuration may also be present. An increase in probing depth is often observed in the presence of peri-implant mucositis due to swelling or decrease in probing resistance. There is strong evidence from animal and human experimental studies that plaque is the etiological factor for peri-implant mucositis. Peri-implantitis is a plaque-associated pathological condition occurring in tissues around dental implants, characterized by inflammation in the peri-implant mucosa and subsequent progressive loss of supporting bone. Peri-implantitis sites exhibit clinical signs of inflammation, bleeding on probing, and/or suppuration, increased probing depths and/or recession of the mucosal margin in addition to radiographic bone loss. The evidence is equivocal regarding the effect of keratinized mucosa on the long-term health of the peri-implant tissue. It appears, however, that keratinized mucosa may have advantages regarding patient comfort and ease of plaque removal. Case definitions in day-to-day clinical practice and in epidemiological or disease-surveillance studies for peri-implant health, peri-implant mucositis, and peri-implantitis were introduced. The proposed case definitions should be viewed within the context that there is no generic implant and that there are numerous implant designs with different surface characteristics, surgical and loading protocols. It is recommended that the clinician obtain baseline radiographic and probing measurements following the completion of the implant-supported prosthesis.
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http://dx.doi.org/10.1111/jcpe.12957DOI Listing
June 2018

A systematic review and meta-analysis of the survival rate of implants placed in previously failed sites.

Braz Oral Res 2018 3;32:e27. Epub 2018 May 3.

Department of Stomatology, School of Dentistry, Universidade de São Paulo - USP, São Paulo, Brazil.

The aim of this study was to conduct a systematic review and meta-analysis to assess the clinical outcomes of dental implants placed in previously early and late implant failed sites. An electronic literature search was conducted in several databases for articles published up to February 2018. Human clinical trials that received at least one implant in a previously failed site were included. Hence, the PICO question that was aimed to be addressed was: Do patients undergoing implant replacement (second and third attempts) in previous failed sites have survival rates similar to implants placed at first attempts? A random effects model was used to calculate survival weighted means and corresponding 95% Confidence Intervals (CI) among studies. Eleven studies of low to moderate methodological quality were included in this review. Implants placed in sites with history of one and two implant failures had a weighted survival rate (SR) of 88.7% (95%CI 81.7-93.3) and 67.1% (95%CI 51.1-79.9), respectively. Implants placed in sites with a previous early failure revealed a weighted SR of 91.8% (95%CI 85.1-95.6). First implants presented higher SR than implants placed in sites with one or two previous implant failures. In contrast, implants placed in sites with one and two implant failures had similar SR. Within its limitations, this review suggests that replacement implants have moderate SR. Larger prospective studies with well-defined criteria for early and late implant failure are necessary to confirm and expand on these results.
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http://dx.doi.org/10.1590/1807-3107bor-2018.vol32.0027DOI Listing
May 2018

Osseous Healing Around Immediate Implants Placed Using Contour Augmentation: A Prospective Case Series.

Int J Periodontics Restorative Dent 2017 Nov/Dec;37(6):883-891

The purpose of this study was to prospectively evaluate the dimensional bone changes around implants placed immediately with buccal contour augmentation. Patients with hopeless maxillary anterior teeth were treated with extraction, immediate implant placement, and simultaneous buccal contour augmentation. Hard tissue measurements were recorded at the time of implant placement and after 3 months of healing. All implants (N = 18) successfully osseointegrated with a mean buccal bone thickness of 2.94 ± 0.21 mm (mean ± SE) at the implant platform. This was significantly greater compared to previous data on immediate implants placed without contour augmentation (2.32 ± 0.17 mm). Buccal contour augmentation in conjunction with immediate implant placement significantly increased peri-implant buccal bone thickness after 3 months of healing.
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http://dx.doi.org/10.11607/prd.3157DOI Listing
July 2018

Thickness of the Buccal Plate in Posterior Teeth: A Prospective Cone Beam Computed Tomography Study.

Int J Periodontics Restorative Dent 2017 Nov/Dec;37(6):801-807

Buccal plate thickness is an important clinical parameter for postextraction implant treatment planning. The purpose of this study was to assess buccal plate thickness of the posterior maxilla and mandible using cone beam computed tomography (CBCT). A total of 265 patients and 934 teeth met the inclusion criteria for this study. CBCT volumes were taken and aligned for measurement at the ideal midsagittal cross-section. Buccal plate thickness was measured at 1, 3, and 5 mm apical to the alveolar crest. The frequency of thick (≥ 1 mm), thin (< 1 mm), and radiographic absence of the buccal plate were determined. The frequency of thin buccal plate decreases from anterior to posterior, with first premolars and first molar mesial roots most affected. Radiographic absence of the buccal plate was more common in the mandible, at first premolars, and among women. Thin and absent buccal plate are not uncommon in the posterior jaws; consequently, ridge preservation may be indicated even at posterior teeth.
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http://dx.doi.org/10.11607/prd.2642DOI Listing
July 2018

The influence of collagen membrane and autogenous bone chips on bone augmentation in the anterior maxilla: a preclinical study.

Clin Oral Implants Res 2017 Nov 25;28(11):1368-1380. Epub 2016 Dec 25.

Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland.

Objectives: To evaluate the effect of a resorbable collagen membrane and autogenous bone chips combined with deproteinized bovine bone mineral (DBBM) on the healing of buccal dehiscence-type defects.

Material And Methods: The second incisors and the first premolars were extracted in the maxilla of eight mongrels. Reduced diameter, bone-level implants were placed 5 weeks later. Standardized buccal dehiscence-type defects were created and grafted at implant surgery. According to an allocation algorithm, the graft composition of each of the four maxillary sites was DBBM + membrane (group D + M), autogenous bone chips + DBBM + membrane (group A + D + M), DBBM alone (group D) or autogenous bone chips + DBBM (group A + D). Four animals were sacrificed after 3 weeks of healing and four animals after 12 weeks. Histological and histomorphometric analyses were performed on oro-facial sections.

Results: The pattern of bone formation and resorption within the grafted area showed high variability among the same group and healing time. The histomorphometric analysis of the 3-week specimens showed a positive effect of autogenous bone chips on both implant osseointegration and bone formation into the grafted region (P < 0.05). The presence of the collagen membrane correlated with greater bone formation around the DBBM particles and greater bone formation in the grafted region after 12 weeks of healing (P < 0.05). The oro-facial width of the augmented region at the level of the implant shoulder was significantly reduced in cases where damage of the protection splints occurred in the first week of healing (P < 0.05).

Conclusions: The addition of autogenous bone chips and the presence of the collagen membrane increased bone formation around DBBM particles. Wound protection from mechanical noxa during early healing may be critical for bone formation within the grafted area.
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http://dx.doi.org/10.1111/clr.12996DOI Listing
November 2017

Evaluation of Healing at Molar Extraction Sites With and Without Ridge Preservation: A Randomized Controlled Clinical Trial.

J Periodontol 2017 03 27;88(3):241-249. Epub 2016 Oct 27.

Department of Periodontics, University of Texas Health Science Center San Antonio, San Antonio, TX.

Background: To date, limited evidence is available specifically evaluating ridge preservation (RP) and implant placement in molar sites. The primary aim of this study is to radiographically compare alveolar ridge changes with and without RP with cone-beam computed tomography (CBCT).

Methods: This parallel, two-arm randomized clinical trial included 40 patients evenly distributed between two treatment groups. After molar extraction, sites were allowed to heal naturally or received RP with freeze-dried bone allograft covered by a non-resorbable dense polytetrafluoroethylene membrane. CBCT scans were taken immediately and 3 months postextraction, and then a dental implant was placed. Width and height measurements were made radiographically.

Results: Significantly greater loss in alveolar ridge height was found in molar sites allowed to heal without RP on the buccal aspect of the socket (RP: -1.12 ± 1.60 mm versus no RP: -2.60 ± 2.06 mm, P = 0.01). No significant difference in ridge width loss was found between groups. Two-thirds ridge width reduction was experienced on the buccal aspect in sites without RP, but width loss was evenly distributed between buccal and lingual aspects when RP was performed. Bone grafting at time of placement was required in 25% of implants in the group without RP versus 10% of implants in the RP group.

Conclusions: In molar extraction sites without RP, significantly more reduction in ridge height occurred, and the majority of ridge width loss was localized to the buccal aspect. When RP was performed, ridge width loss was not significantly decreased, but the loss was evenly distributed between facial and lingual aspects of the extraction site.
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http://dx.doi.org/10.1902/jop.2016.160445DOI Listing
March 2017

Efficacy of stem cells on the healing of peri-implant defects: systematic review of preclinical studies.

Clin Exp Dent Res 2016 Jun 4;2(1):18-34. Epub 2016 Feb 4.

Division of Periodontics, Department of Stomatology, School of Dentistry University of São Paulo São Paulo São Paulo Brazil.

This systematic review considers the evidence from animal studies evaluating the effectiveness of mesenchymal stem cells (MSC) in the treatment of intraoral peri-implant defects. MEDLINE, EMBASE, and LILACS databases were searched for quantitative preclinical controlled animal model studies that evaluated the effect of MSC on bone healing at intraoral peri-implant bone defects. The primary outcome was the amount of (re-)osseointegration reported as bone-to-implant contact in the defect area. The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement guidelines. Ten studies met the inclusion criteria. Only one study induced peri-implant inflammation to produce peri-implant bone defects. In all others, defects were surgically created at implant installation. Differences in defect morphology were identified among the studies. Both xenogenous and autogenous MSC were used to treat peri-implant defects. These included bone marrow-derived MSC, periodontal ligament-derived MSC, umbilical cord MSC, bone marrow-derived mononuclear cells, and peripheral blood mononuclear cells. Meta-analysis was not possible because of heterogeneities in study designs. Nonetheless, in most studies, local MSC implantation was not associated with adverse effects and had a positive effect on bone healing around peri-implant defects. Combination of MSC with membranes and bioactive factors appears to provide improved treatment outcomes. In large animal models, intraoral use of MSC may provide beneficial effects on bone healing within peri-implant defects. The various degrees of success of MSC in peri-implant bone healing are likely to be related to the use of cells from various populations, tissues, and donor species. However, human safety and efficacy must be demonstrated before its clinical use can be considered.
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http://dx.doi.org/10.1002/cre2.16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5839227PMC
June 2016

A cone beam computed tomography (CBCT) study of buccal plate thickness of the maxillary and mandibular posterior dentition.

Clin Oral Implants Res 2016 Sep 14;27(9):1072-8. Epub 2015 Sep 14.

Department of Periodontics, University of Texas Health Science Center San Antonio, San Antonio, TX, USA.

Background: Buccal plate thickness is of clinical importance in treatment planning for implants. The purpose of this study was to evaluate the buccal plate thickness in posterior dentate areas of both the maxilla and mandible using cone beam computed tomography in order to estimate the approximate distributions of this anatomic variable.

Methods: Two hundred and sixty-five subjects were included for a total of nine hundred and thirty-four roots assessed by cone beam computed tomography. CBCT scans were taken and evaluated at the ideal buccolingual cross-sections of each root at 1 mm, 3 mm, and 5 mm apical to the alveolar crest to measure buccal plate thickness. Data are reported by geometric means and 95% confidence intervals.

Results: Both arches demonstrated increasing buccal plate thickness from anterior to posterior. Maxillary teeth had a significant decrease in thickness from coronal to apical along the tooth root (P < 0.001), except at second molars. The first premolar and mesial root of the first molar were significantly thinner than all other roots in the maxilla. Conversely, the mandible demonstrated a significant increase in buccal plate thickness from coronal to apical (P < 0.001). The premolars were significantly thinner than all other roots. Age and sex were found to have limited impact on buccal plate thickness in both arches.

Conclusions: Buccal plate thickness is highly dependent upon the arch position, tooth location, and measurement point, but age and sex have limited impact.
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http://dx.doi.org/10.1111/clr.12688DOI Listing
September 2016

Periodontal Biotype: Gingival Thickness as It Relates to Probe Visibility and Buccal Plate Thickness.

J Periodontol 2015 Oct 25;86(10):1141-9. Epub 2015 Jun 25.

Department of Periodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX.

Background: Probe visibility is the clinical gold standard to discriminate thick from thin biotype but is prone to subjective interpretation. The primary objective of this study is to determine at what objective gingival thickness the probe becomes invisible through the tissue. A secondary objective is to compare mean buccal plate thickness between thick and thin biotypes as determined by probe visibility.

Methods: Maxillary anterior teeth (n = 306) were studied in 56 human patients. Biotype was determined by probe visibility through the tissue. Gingival thickness was measured via transgingival sounding. Buccal plate thickness was measured (n = 66 teeth) by cone beam computed tomography. For the primary objective, the gingival thickness that best corresponded with probe invisibility was selected using the receiver operating characteristic and area under the curve (AUC) with the highest combination of sensitivity and specificity. For the secondary objective, mean buccal plate thickness was compared between sites in which the probe was visible and when it was not (Student t test, α= 0.05).

Results: The gingival thickness that most closely corresponded with probe invisibility was >0.8 mm (0.666 AUC, 67.7% sensitivity, 65.4% specificity). When the probe was visible, mean gingival thickness was 0.17 mm less (P <0.001) compared to the "thick" counterparts. When the probe was visible, mean buccal plate thickness tended to be smaller by 0.212 mm (P = 0.08), but the difference was not statistically significant.

Conclusions: The study failed to identify a gingival thickness threshold that can discriminate reliably between sites in which the probe was visible (i.e., thin biotype) and those in which it was not (i.e., thick biotype). Probe visibility was associated with thinner measurements of gingival thickness and showed a tendency to be associated with a thinner buccal plate.
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http://dx.doi.org/10.1902/jop.2015.140394DOI Listing
October 2015

Crown-to-implant ratio: what is the latest?

Authors:
Guy Huynh-Ba

Int J Oral Maxillofac Implants 2015 Mar-Apr;30(2):259-61

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May 2015

Esthetic, clinical and patient-centered outcomes of immediately placed implants (Type 1) and early placed implants (Type 2): preliminary 3-month results of an ongoing randomized controlled clinical trial.

Clin Oral Implants Res 2016 Feb 10;27(2):241-52. Epub 2015 Mar 10.

Department of Pathology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.

Aim: The objective of the study was to compare (i) esthetic, (ii) clinical and (iii) patient-centered outcomes following immediate (Type 1) and early implant placement (Type 2).

Material And Methods: Thirty-eight subjects needing a single extraction (premolar to premolar) were randomly allocated to Type 1 or Type 2 implant placement. Three months following permanent crown insertion, evaluation of (i) esthetic outcomes using soft tissue positions, and the pink and white esthetic scores (PES/WES), (ii) clinical performance using probing pocket depth (PPD), modified plaque index (mPI) and modified sulcus bleeding index (mSBI) around each implant and (iii) patient satisfaction by means of a questionnaire using a visual analogue scale (VAS) was performed.

Results: Thirty-two patients completed the 3-month follow-up examination (Type 1, n = 17; Type 2, n = 15) with a 100% implant survival rate. Type 1 implants lost 0.54 ± 0.18 mm of mid-facial soft tissue height, while Type 2 implants lost 0.47 ± 0.31 mm (P > 0.05). The papillae height on the mesial and distal was reduced about 1 mm following both procedures. The PES/WES following Type 1 implant placement amounted to 13.7 ± 0.6 and 12.5 ± 0.7 in the Type 2 group (P > 0.05). PPD, mPI and mSBI were low in both groups (P > 0.05). Patient-centered outcomes failed to demonstrate any statistical difference between the two cohorts.

Conclusion: Three months following final crown delivery, there were no significant differences in esthetic, clinical and patient-centered outcomes following Type 1 and Type 2 implant placement. On the short term, one may achieve good optimal esthetic and clinical results irrespective of these two placement protocols. These results need to be confirmed on the long term.
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http://dx.doi.org/10.1111/clr.12577DOI Listing
February 2016

Formulating a global prognosis and treatment plan for the periodontally compromised patient: a reconstructive vs. an adaptive approach.

Compend Contin Educ Dent 2014 Oct;35(9):668-70, 672-3, 676-7

Associate Professor, Department of Periodontics, University of Texas Health Science Center at San Antonio Dental School, San Antonio, Texas.

The clinician faces treatment planning challenges when patients present with generalized severe chronic periodontitis that may result in tooth loss. This article provides a treatment planning discussion along with approaches for treating such patients. It presents the clinical question: What is the best means for approaching treatment planning in a patient with severe periodontitis requiring extraction and replacement of some teeth? Two treatment approaches are discussed—a reconstructive approach versus an adaptive one—both of which have an end goal of achieving periodontal health and occlusal stability, and each has its own advantages and disadvantages. In conclusion, utilizing a global prognostic approach will assist clinicians anticipate the eventual restorative needs of patients and prescribe customized periodontal and restorative therapies that best address those needs.
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October 2014

The effects of elevated hemoglobin A(1c) in patients with type 2 diabetes mellitus on dental implants: Survival and stability at one year.

J Am Dent Assoc 2014 Dec;145(12):1218-26

Dr. McMahan is a professor, Department of Pathology, University of Texas Health Science Center at San Antonio.

Background: The authors conducted a prospective cohort study to determine whether poor glycemic control is a contraindication to implant therapy in patients with type 2 diabetes.

Methods: The study sample consisted of 117 edentulous patients, each of whom received two mandibular implants, for a total of 234 implants. Implant-retained mandibular overdentures were loaded after a four-month healing period and followed up for an additional one year. The authors assessed implant survival and stability (by means of resonance frequency analysis) relative to glycated hemoglobin A1c (HbA1c) levels, with baseline levels up to 11.1 percent and levels as high as 13.3 percent over one year.

Results: Implant survival rates for 110 of 117 patients who were followed up for one year after loading were 99.0 percent, 98.9 percent and 100 percent, respectively, for patients who did not have diabetes (n = 47), those with well-controlled diabetes (n = 44) and those with poorly controlled diabetes (n = 19). The authors considered the seven patients lost to follow-up as having had failed implants; consequently, their conservative estimates of survival rates in the three groups were 93.0 percent, 92.6 percent and 95.0 percent (P = .6510). Two implants failed at four weeks, one in the nondiabetes group and the other in the well-controlled diabetes group. Delays in implant stabilization were related directly to poor glycemic control.

Conclusions: The results of this study indicate that elevated HbA1c levels in patients with type 2 diabetes were not associated with altered implant survival one year after loading. However, alterations in early bone healing and implant stability were associated with hyperglycemia.
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http://dx.doi.org/10.14219/jada.2014.93DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4403726PMC
December 2014

A lateral ridge augmentation study to evaluate a synthetic membrane for guided bone regeneration: an experiment in the canine mandible.

Clin Oral Implants Res 2016 Jan 10;27(1):73-82. Epub 2014 Nov 10.

Department of Periodontics, University of Texas Health Science Center at San Antonio (UTHSCSA), San Antonio, TX, USA.

Objectives: To evaluate guided bone regeneration outcomes in defects protected with an in situ formed polyethylene glycol (PEG) hydrogel membrane as compared to a non-cross-linked collagen membrane (CM).

Material And Methods: Four mandibular alveolar ridge defects were created in eight hound dogs. Regenerative procedures were randomly allocated to one of four groups consisting of freeze-dried bone allograft, which is referred to in this study as freeze-dried bone xenograft (FDBX) + PEG, autogenous bone (AB) + PEG, AB + CM, and AB alone. After 8 weeks, titanium dental implants were placed into augmented sites. After 8 weeks of allowed time for osseointegration, the animals were sacrificed to harvest block specimens for bone-to-implant contact (BIC) and ridge width histomorphometric analysis.

Results: Polyethylene glycol membranes had an exposure rate of 50% as compared to 12.5% for sites grafted with CM. Regenerative outcomes with respect to implant placement were least favorable for FDBX + PEG which had implants placed in 37.5% of augmented sites compared to 100% implant placement for all other groups. No statistically significant differences were noted between groups for ridge width measurements in implant and non-implant histologic sections (P > 0.05). Buccal BIC (%) values between treatment groups also failed to reach statistical significant difference (FDBX + PEG [60.2 ± 9.4]; AB + PEG [58.8 ± 8.5]; AB + CM [57.9 ± 12.8]; AB [61.0 ± 10.2]).

Conclusion: When used in conjunction with FDBX, PEG had unpredictable bone formation and in most cases negatively impacted future implant placement.
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http://dx.doi.org/10.1111/clr.12517DOI Listing
January 2016

Biologic width around different implant-abutment interface configurations. A radiographic evaluation of the effect of horizontal offset and concave abutment profile in the canine mandible.

Int J Oral Maxillofac Implants 2014 Sep-Oct;29(5):1114-22

Purpose: The purpose of this experimental study was to analyze radiographically in a dog model how different implant-abutment interface configurations influence alveolar crestal bone changes.

Materials And Methods: Six different experimental implant-abutment connections were evaluated in six mixed-breed dogs. The following parameters were tested: absence of microgap, microgap proximal to bone crest, and microgap distant from bone crest. In addition, two different cervical abutment profiles, one straight and one featuring a supracrestal concavity, were evaluated. Implants were based on a cylindrical full-body screw design and made from cold-worked grade IV commercially pure titanium. The diameter (at thread tips) measured 4.1 mm, whereas the inner diameter was 3.5 mm. Standardized periapical digital radiographs were obtained for comparative analysis at baseline and at 3, 4, 5, 6, 7, 8, and 9 months after implant placement. Radiographs were randomized and calibrated for linear measurements. For statistical analysis, mixed-model repeated-measures analysis of variance was used.

Results: All implants integrated successfully and remained stable during the entire period of the study. Radiographically, when comparing groups with straight profiles, crestal bone remodeling in group C (one-piece design) was significantly less than in group A (matching diameters) and B (nonmatching diameters). In fact, implant group C showed the least crestal bone remodeling of all groups. When comparing groups with a concave profile but different microgap configurations, all three designs demonstrated bone loss with no significant differences among the three groups.

Conclusion: A nonsubmerged one-piece implant design demonstrated the least amount of bone remodeling of all groups. Implant-abutment connections with a concave profile established crestal bone levels immediately apical to the concavity regardless of the microgap variable.
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http://dx.doi.org/10.11607/jomi.3068DOI Listing
May 2015

"All-on-four": where are we now?

Int J Oral Maxillofac Implants 2014 Mar-Apr;29(2):285-8

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June 2014

Soft tissue augmentation procedures for mucogingival defects in esthetic sites.

Int J Oral Maxillofac Implants 2014 ;29 Suppl:155-85

Purpose: This systematic review was performed to address the focus question: "In adult patients with soft tissue deficiencies around maxillary anterior implants, what is the effect on esthetic outcomes when a soft tissue procedure is performed?" In addition, this paper reviews the importance of presurgical esthetic risk assessment (ERA) starting with comprehensive team case planning prior to surgical intervention and a restorative-driven approach.

Materials And Methods: A thorough Medline database search performed on related MeSH terms yielded 1,532 titles and selected abstracts that were independently screened. Out of the 351 abstracts selected, 123 full-text articles were obtained for further evaluation. At each level, any disagreements were discussed until a consensus was reached.

Results: A total of 18 studies were included in this systematic review of esthetic outcomes following soft tissue procedures around implants with soft tissue deficiencies. A preliminary analysis of the included studies showed that the vast majority were case series studies with most not providing objective outcomes of their results. Moreover, only one randomized controlled trial was identified. Therefore, quantitative data analysis and subsequent meta-analysis could not be performed. The included studies were grouped according to the intervention on the peri-implant soft tissue performed and six groups were identified. The periodontal procedures performed around dental implants gave initial good results from the inflammation involved in wound healing, but in virtually all cases significant recession occurred as healing resolved and the tissues matured.

Conclusions: Although success of implant therapy is similar in the anterior maxilla and other areas of the mouth, the majority of studies evaluating this therapy in the esthetic zone are lacking literature support, few in number, devoid of long-term follow-up and number of patients, and are subject to inclusion bias. The use of the ERA tool for all esthetic zone cases can benefit both the clinician and the patient to avoid any miscommunication and problems of expectation upon completion. All the available knowledge on this topic, including the approaches described in this paper, is based on a very limited literature support and thus should be addressed with caution. These concerns should encourage long-term good clinical trials for better assessment of those issues.
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http://dx.doi.org/10.11607/jomi.2014suppl.g3.2DOI Listing
June 2014