Effect of Er:YAG laser on debonding zirconia and lithium disilicate crowns bonded with 2- and 1-bottle adhesive resin cements.

INTRODUCTION: Erbium-doped yttrium-aluminum-garnet (Er:YAG) laser debonding of zirconia and lithium disilicate restorations is increasingly used for a range of clinical applications. Using rotary instruments to remove such restorations for any purpose has proven to be challenging. Erbium laser has been reported to be a conservative method for removing ceramic restorations. There is little data in the literature about the effect of adhesive resin cement type on the debonding time of the ceramic restoration using the Er:YAG laser. OBJECTIVES: To evaluate and compare the time required for the Er:YAG laser to debond zirconia and lithium disilicate crowns bonded with a 2- and 1-bottle adhesive resin cement systems. MATERIALS AND METHODS: Forty extracted premolar teeth were prepared and scanned for milled 40 CAD/CAM crowns. Teeth were randomly assigned into groups (n = 10 per group): 3 mol% yttria-partially stabilized zirconia crowns 3Y-PSZ (G1a) bonded with Panavia™ V5 (2-bottle adhesive resin cement), Zirconia 3Y-PSZ crowns (G1b) bonded with RelyX™ Ultimate (1-bottle adhesive resin cement), and for the lithium disilicate crowns bonded with the two types of cements (G2a, G2b). Each specimen was irradiated with an Er:YAG laser at 335 mJ, 15 Hz, 5.0 W, and 50-ms pulse duration (super short pulse mode). The irradiation time required for crowns to be successfully debonded was recorded for each specimen. Data were statistically analyzed using ANOVA and Tukey HSD post-hoc test (p < 0.05), at the 95 percent level of confidence. The intaglio surface of the debonded crown was analyzed using scanning electron microscopy (SEM). RESULTS: The mean ± standard deviation times needed for crown debonding were 5.75 ± 2.00 min for the G1a group, 4.79 ± 1.20 min for group G1b, 1.69 ± 0.49 min for group G2a, and 1.12 ± 0.17 for group G2b. There was no statistically significant difference in debonding time between the 2- and 1- bottle adhesive resin cement within the groups G1a and b (p = 0.2914), or between groups G2a b (p = 0.7116). A statistically significant difference (p < 0.05) was found between groups G1a and G2a and b and between groups G1b and G2a and b were SEM analysis showed no changes in the microstructure of the ceramic surface after Er:YAG laser irradiation. CONCLUSION: Zirconia and lithium disilicate restorations can be debonded using Er:YAG lasers in a safe and efficient manner. There is no significant difference in the debonding time between the 2- and 1- bottle adhesive resin cement systems used in this study. CLINICAL SIGNIFICANCE: Retrieving zirconia and lithium disilicate ceramics can be a challenging process when using diamond rotary instruments. ER:YAG lasers may efficiently debond these ceramics from the tooth structure, independent of the bonding process used for bonding them.

Er:YAG laser debonding of zirconia and lithium disilicate restorations.

STATEMENT OF PROBLEM: Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) restorations of different formulations are being used increasingly in monolithic form for a range of clinical applications. Using rotary instruments to remove such restorations for any purpose is challenging, but they can be removed conservatively with erbium lasers. However, studies on how a laser penetrates different zirconias to break the cement bond between the tooth surface and the zirconia are lacking. PURPOSE: The purpose of this in vitro study was to evaluate and compare the time required for an erbium-doped yttrium-aluminum-garnet (Er:YAG) laser to remove different types of zirconia and lithium disilicate crowns. MATERIAL AND METHODS: Forty extracted premolar teeth were prepared, scanned, designed, and milled to fabricate 40 computer-aided design and computer-aided manufacturing (CAD-CAM) crowns, which were assigned to 4 groups (n=10): 3 mol% Y-TZP, 4 mol% Y-TZP, 5 mol% Y-TZP, and lithium disilicate as a control. All crowns were bonded to the teeth with a self-adhesive resin cement (Panavia SA Cement Universal). Each specimen was irradiated with an Er:YAG laser with the following parameters: 300 mJ, 15 Hz, 5.0 W, and a 50-microsecond pulse duration (supershort pulse mode). The irradiation time required for crowns to be retrieved successfully was recorded for each specimen. Data were statistically analyzed using analysis of variance and the Tukey honestly significant difference post hoc test (α=.05). The intaglio surfaces of the restorations were analyzed using scanning electron microscopy (SEM). RESULTS: The mean ±standard deviation times in minutes needed for crown debonding were 12.46 ±4.17 for the 3 mol% Y-TZP group, 10.30 ±3.33 for the 4 mol% Y-TZP group, 4.03 ±1.62 for the 5 mol% Y-TZP group, and 2.08 ±0.92 for the lithium disilicate group. A statistically significant difference (P<.05) in the debonding time was found for all investigated groups, expect between the 3 mol% and 4 mol% Y-TZP groups and between the 5 mol% Y-TZP and lithium disilicate groups. SEM analysis of the ceramic surfaces showed no visual damage associated with Er:YAG laser irradiation. CONCLUSIONS: Zirconia crown retrieval time with the Er:YAG laser was influenced by the yttria content of the zirconia, with decreasing retrieval time with increasing yttria content. Er:YAG laser debonding of zirconia crowns is a noninvasive, efficient, and rapid approach to the removal of crowns and could be applied in clinical practice.

Comparison of Accuracy and Time for Four Implant Placement Techniques Supporting Fixed-Partial Denture.

Various guiding methods are used to place implants. This ex vivo pilot study used a convenience sample to examine time and accuracy for placement of 2 dental implants supporting a 3-unit fixed prosthesis on a simulation model using freehand and 3 guided placement techniques. Four operators with no prior implant placement experiences were randomly assigned placement of 2 maxillary or mandibular implants for a fixed prosthesis. Techniques included dynamic navigation (DN), static guide (SG), template-based guide (TBG), and freehand placement (FH). Preoperative and operative times were recorded. Discrepancies between the planned and placed implant positions were assessed by superimposing preoperative and postoperative cone beam computerized tomography scans. Data were analyzed with repeated-measures regression with Tukey's adjusted pairwise comparisons (α = 0.05). Dynamic navigation was associated with the longest operative time (13.5 minutes vs 5-10.2, P = .0001) but overall fastest when incorporating preoperative time (32.1 minutes vs 143-181.5, P < .0001). All deviation measures were significantly associated with the placement method (P < .05) except apex vertical deviation (P = .3925). Implants placed by SG had significantly lower entry 2-dimensional deviation than the other methods, particularly on the mandible. The DN and SG methods had significantly lower Apex 3D and overall angle deviations, again particularly on the mandible. The mandible had significantly higher deviations than maxilla. Within limitations of this study, implant placement by novice operators is more accurate when using dynamic and static guidance compared to freehand and template-based techniques.

Tracking Tag Stabilization With a Small-Diameter Implant in an Edentulous Mandible to Assist Dynamically Navigated Surgery: A Case Report.

This report describes the use of a temporary dental implant to secure a radiographic fiducial marker and patient-tracking tag to an edentulous mandible for dynamically guided implant placement into a fibula microvascular free flap. A small-diameter dental implant was placed into the anterior mandible to secure a radiographic fiducial marker followed by a patient tag. The patient tag allowed for tracking of the patient's mandible during placement of endosseous dental implants. Four endosseous dental implants were successfully placed into the edentulous fibula free flap mandibular reconstruction. Dynamic navigation using a small-diameter implant to secure radiographic fiducial markers and patient tags provides a novel technique to place implants into an edentulous microvascular free flap with minimal incision and reflection of soft tissue.

Erbium laser-assisted ceramic debonding: a scoping review.

PURPOSE: Removal of ceramic restorations and appliances can be time consuming, invasive, and inconvenient. Erbium lasers offer an alternative noninvasive method for debonding of ceramic appliances. This paper aims to provide a comprehensive review of current literature on the effectiveness of erbium lasers for removal of ceramic restorations and appliances from natural teeth and dental implants. METHODS: A comprehensive search of 7 databases, including Medline (Ovid), Embase, Dentistry and Oral Sciences Source (DOSS), Web of Science, Cochrane Library, and ProQuest Dissertations and Theses was performed. The inclusion and exclusion criteria were agreed prior to the literature search. Two reviewers independently screened the title and abstract. A third reviewer then broke the tie, if any. The selected articles then underwent full text review and the data was extracted. RESULTS: The search identified 4117 unique articles published through June 10, 2021. Studies were assessed and categorized based on the type of restoration/appliance, type of abutment, type of laser, laser settings, efficacy of debonding, and pulpal temperature rise. Thirty-eight full-text articles were reviewed for inclusion. Time for ceramic debonding varies depending on the type of restorations and materials. Removal of zirconia crowns from teeth and implant abutments requires a longer period of time compared to lithium disilicate crowns. Temperature increases were reported as 5.5 degrees or less. Laser setting and laser type affect the debonding time and the increase in temperature. Examinations of debonded ceramics demonstrated no known structural damages resulting from laser applications. CONCLUSIONS: Erbium lasers are effective noninvasive tools to remove all ceramic restorations/appliances from natural teeth and implant abutments without causing harm to abutments. Laser-assisted debonding should be considered as a viable alternative to rotary instrumentation for ceramic crowns; however, clinical studies of erbium-assisted ceramic retrieval are needed.

In Vitro Comparison of Time and Accuracy of Implant Placement Using Trephine and Conventional Drilling Techniques Under Dynamic Navigation.

The aim of this randomized in vitro study was to compare the time and accuracy of implant-site preparation and implant placement using a trephine drill versus a conventional drilling technique under dynamic navigation. In total, 42 implants were placed in simulation jaw models with the 2 drilling techniques by 2 operators who had previous experience with dynamic navigation. The timing of each implant placement was recorded, and horizontal, vertical, and angulation discrepancies between the planned and placed implants were compared. There was no significant difference in time or accuracy between the trephine and conventional drilling techniques. Implant-site preparation with a single trephine drill using dynamic navigation was as accurate under in vitro experimental conditions as a conventional drilling sequence.

Retrieval of Glass Fiber Post Using Er:YAG Laser and Conventional Endodontic Ultrasonic Method: An In Vitro Study.

PURPOSE: To compare the times and temperatures used to remove a glass fiber post from an endodontically treated tooth using erbium-doped yttrium aluminum garnet (Er:YAG) compared to conventional endodontic ultrasonic method. MATERIALS AND METHODS: Thirty-four single-root human extracted teeth were endodontically treated ex vivo. The post space was prepared to 7 mm in depth and a 11.4 mm glass fiber post was cemented using composite resin cement. Specimens were kept in 100% humidity for 24 hours and then randomly assigned to Er:YAG laser or ultrasonic methods for post removal. The removal time was recorded. Specimens with a fractured post during the removal process were excluded. The temperature on the external surface of the root was measured at the coronal, middle, and apical third portions during the laser or ultrasonic applications from 1 to 10 minutes. Data were analyzed using one-tailed t-test and paired t-test (ɑ = 0.01) for the post removal time and temperature difference, respectively. The specimen surfaces were examined using scanning electron microscopy (SEM). RESULTS: Fifteen specimens were tested in each group. Four specimens were fractured, 2 in the laser and 1 in ultrasonic group. One post was excluded because of laser tip damage. The average removal time were 98 ± 46.1 seconds for Er:YAG laser and 538 ± 215.6 seconds or ultrasonic groups with significant difference between the groups (p < 0.001). The temperature (°C) ranges measured from 1 to 10 minutes were [24.2°, 27.3°] for laser and [33.0°, 38.0°] for ultrasonic in the cervical area, [22.1°,24.6°] for laser and [31.0°, 34.6°] for ultrasonic in the middle area, and [24.4°, 27.7°] for laser and [30.3°, 34.1°] for ultrasonic in the apical area. There were significant differences between temperatures for each treatment (p < 0.001). SEM examination showed no visible damage caused by treatment with Er:YAG laser. CONCLUSIONS: Er:YAG laser can remove posts up to 5 times faster than ultrasonic removal method. The laser causes lower temperature increase at the root surface compared to the ultrasonic removal. Er:YAG may be considered as a viable alternative to sonication for post removal.

In Vitro Examination of the Use of Er:YAG Laser to Retrieve Lithium Disilicate Crowns from Titanium Implant Abutments.

PURPOSE: Removal of cement-retained implant crowns can be difficult and often requires sectioning of the prosthesis by rotary instruments. This study aimed to measure how much time is required in crown removal and the temperature changes when erbium-doped yttrium aluminum garnet (Er:YAG) laser was used to retrieve lithium disilicate crowns from titanium implant abutments luted with composite resin (CR) cement and resin-modified glass ionomer (RMGI). MATERIALS AND METHODS: Forty identical lithium disilicate crowns were fabricated for prefabricated titanium abutments. CR and RMGI cements were used to lute the crowns, 20 specimens for each cement. Specimens were kept in 100% humidity for 48 hours. Er:YAG laser was then used to facilitate the crown retrieval. The retrieval time was recorded. The temperature changes at the abutment level for each type of cement were recorded during irradiation of 10 specimens for each type of cement from 1 to 10 minutes. Data were analyzed using t-test (ɑ = 0.01) and paired t-test (ɑ = 0.05). The surfaces of the crown and the abutment were further examined using scanning electron microscopy (SEM). RESULTS: The average times of crown removal from titanium abutments were 196.5 seconds for CR and 97.5 seconds for RMGI groups with statistical significance (p < 0.001). The temperatures measured from 1 to 10 minutes of irradiation ranged from 18° to 20.8° for CR and 18° to 23° for RMGI at the abutment surface, and 22.1° to 24.6° for CR and 22° to 24.8° for RMGI at the crown surface. No statistical differences were observed between temperature changes at the abutment or the crown for each cement (p = 0.63); however, there was a statistically significant difference between the temperatures at the abutment and crown for both cements (p < 0.001). SEM examination showed no visible damage caused by treatment with Er:YAG laser. CONCLUSIONS: It is faster to remove lithium disilicate crowns from titanium implant abutments when luted with RMGI compared to CR cement. The temperature rise was higher in the crown compared to the abutment. The type of cement had no effects on temperature changes. Heat generated from Er:YAG irradiation does not appear to be high enough to have any adverse effect on implant osseointegration.

Periodontal therapy favorably modulates the oral-gut-hepatic axis in cirrhosis.

Cirrhosis is associated with a systemic proinflammatory milieu, endotoxemia, and gut dysbiosis. The oral cavity could be an additional source of inflammation. We aimed to determine the effect of periodontal therapy in cirrhosis through evaluating endotoxemia, inflammation, cognition, and quality of life (QOL). Age-matched cirrhotic and noncirrhotic subjects exhibiting chronic gingivitis and/or mild or moderate periodontitis underwent periodontal therapy with follow-up at 30 days. Saliva/stool for microbial composition and serum for Model for End-stage Liver Disease (MELD) score, endotoxin and lipopolysaccharide binding protein (LBP) and immune-inflammatory markers (IL-1ß; IL-6; histatins 1, 3, 5; and lysozyme) were collected at baseline and day 30. The cognitive function and QOL were also evaluated similarly. A separate group of cirrhotic patients were followed for the same duration without periodontal therapy. Cirrhotics, especially those with hepatic encephalopathy (HE), demonstrated improved dysbiosis in stool and saliva, and improved endotoxin, LBP, and salivary and serum inflammatory mediators following periodontal therapy. These parameters, which were higher in HE at baseline, became statistically similar posttherapy. Pretherapy vs. posttherapy QOL and cognition also improved in HE patients following oral interventions. On the other hand, LBP and endotoxin increased over time in cirrhotic patients not receiving therapy, but the rest of the parameters, including microbiota remained similar over time in the no-therapy group. This proof-of-concept study demonstrates that periodontal therapy in cirrhosis, especially in those with HE, is associated with improved oral and gut dysbiosis, systemic inflammation, MELD score, and cognitive function, which was not observed in those who did not receive therapy over the same time period. NEW & NOTEWORTHY Systematic periodontal therapy in cirrhotic outpatients improved endotoxemia, as well as systemic and local inflammation, and modulated salivary and stool microbial dysbiosis over 30 days. This was associated with improved quality of life and cognition in patients with prior hepatic encephalopathy. In a cirrhotic group that was not provided periodontal therapy, there was an increase in endotoxin and lipopolysaccharide binding protein in the same duration. The oral cavity could be an important underdefined source of inflammation in cirrhosis.

Do Implant Surgical Guides Allow an Adequate Zone of Keratinized Tissue for Flapless Surgery?

PURPOSE: A major advantage of guided implant surgery using 3-dimensionally printed guides is the ability to perform accurate flapless surgery. A drawback of a flapless technique is the inability to manipulate soft tissue to ensure sufficient gingiva around the implant. The purpose of this study was to determine how often flapless surgery using surgical guides results in less than 2 mm of keratinized tissue surrounding the implant. MATERIALS AND METHODS: This retrospective analysis included 27 maxillary and 27 mandibular implant sites that underwent treatment planning for implant-guided surgery using 3Shape Implant Studio (3Shape, Copenhagen, Denmark). Intraoral scan images were used to measure the width of the keratinized tissue on the buccal aspect of each implant site in both arches and the lingual aspect in the mandibular arch. Three examiners measured the amount of buccal and lingual keratinized tissue in millimeters at each implant site. Analysis of variance (P < .05) and correlation coefficients were used to determine statistically significant differences in keratinized tissue among sites. RESULTS: No statistically significant difference was found either between the widths of buccal keratinized tissue in the maxillary anterior (4.06 ± 1.42 mm) and posterior (4.93 ± 2.54 mm) areas (P = .293) or between the amounts of buccal and lingual keratinized tissue in the mandible (P = .995). The keratinized tissue width in the maxillary buccal area was significantly different (4.48 ± 2.04 mm) from that in the mandibular posterior buccal (1.98 ± 1.41 mm) and lingual (1.98 ± 1.23 mm) areas (P < .001). Over 77% of maxillary implant sites had greater than 3 mm of gingiva, and just over 20% had sufficient gingiva in the mandible. CONCLUSIONS: Adequate keratinized tissue was found in most of the planned maxillary implant sites, whereas most of the mandibular posterior implant sites had inadequate keratinized tissue. Therefore, elevation of a flap to preserve and reposition existing keratinized tissue around implants should be considered when planning to use tooth-borne surgical guides in the posterior mandible.

Helicopter Mountain Rescue in Slovenia from 2011 to 2015.

INTRODUCTION: The popularity of adventure recreation in wilderness areas across the world continues to increase. Nevertheless, the risk of injury and illness remains significant. The purpose of this study is to analyze the mountain rescue operations performed in Slovenia between 2011 and 2015. METHODS: This retrospective study reports mountain rescue operations documented by the Slovenian National Mountain Rescue Association. The annual number of ground-based and helicopter-based rescues were identified and compared. For 2015, the indication for rescue and the severity of injury were also analyzed, specifically for interventions requiring the use of a helicopter. RESULTS: From 2011 through 2015, the number of rescues remained consistent with an annual average of 413 (SD ±15; range, 393-434) rescues. However, the percentage of ground-based rescues varied significantly year by year (P=0.016), with highest rate in 2014 (68%) and the lowest in 2015 (56%). In 2015, 434 mountain rescue operations were reported in Slovenia. Injury accounted for 44%, illness for 10%, and fatality for 9% of the rescues. In 37%, no illness or injury was reported. Helicopter rescue was used in 190 (44%) of all interventions. Among the 190 helicopter rescues, 49% of patients had nonfatal injuries, 29% required no medical treatment, 15% had illness, and 7% had fatal injuries. CONCLUSIONS: A significant number of mountain rescue operations were conducted in Slovenia from 2011 through 2015. Most of these were needed for injured, ill, or deceased persons. A notable number of rescues in 2015 required a helicopter.

Simultaneous Impacted Third Molar Extraction and Lateral Ramus Block Graft Harvest for Horizontal Ridge Augmentation: A Case Series.

PURPOSE: The purpose of this study was to confirm the efficiency of using a lateral ramus block graft taken at the time of impacted mandibular third molar removal for horizontal ridge augmentation and implant placement. PATIENTS AND METHODS: Ten patients had grafts obtained from the lateral aspect of the mandible during impacted third molar removal and placed in areas of horizontal ridge deficiency. RESULTS: Measurements made on cone-beam computerized tomograms after 4 months showed gains of 2.7 to 3.5 mm and 16 implants were placed successfully. CONCLUSIONS: In patients with impacted third molars requiring dental implants, simultaneous harvest of a lateral block bone graft is an efficient way of obtaining bone for horizontal ridge augmentation.

Is Cone-Beam Computed Tomography Always Necessary for Dental Implant Placement?

PURPOSE: The use of cone-beam computed tomography (CBCT) for evaluation of patients for dental implants has gained considerable popularity. This retrospective cohort study was designed to determine whether using a clinical examination and a panoramic radiograph (Panorex) for implant selection and determining the need for bone grafting would be comparable to using CBCT in routine implant cases. PATIENTS AND METHODS: Implant size and need for bone grafting were initially determined in 82 patients using a panoramic radiograph and clinical examination. These patients subsequently underwent CBCT and their treatment was re-planned by the same surgeon using Simplant treatment planning software (DENTSPLY Implants, Mölndal, Sweden) in addition to clinical examination. The length and width of implants selected by each method and the need for bone grafting were recorded and the results were compared statistically with each other and with the actual treatment subsequently rendered. RESULTS: The Panorex method and the CBCT method accurately predicted implant width to within 1.5 mm of the implant actually placed in 100% of cases and length to within 1.5 mm in more than 95% of cases. For bone graft prediction, the results indicated that neither the Panorex method nor CBCT method differed substantially from the actual treatment rendered. CONCLUSIONS: The results of this study indicate that the CBCT is more accurate in predicting implant length and width and the need for bone grafting procedures. However, for routine unguided implant placement in sites where anatomic structures and bone grafting are not a concern, the use of a panoramic radiograph could be adequate for determining the length and width of the implant.

Public and Patient Knowledge About Dental Implants.

PURPOSE: The more informed a patient is about a given procedure, the better the ultimate outcome. This study was designed to compare general public awareness and knowledge regarding oral implant treatment with those of patients presenting for such treatment and to determine the sources from which they may have obtained such information, as well as the accuracy of the information. PATIENTS AND METHODS: In this cross-sectional study, 2 groups of patients were asked to complete a questionnaire containing implant knowledge questions and questions regarding any sources they may have used to obtain information about dental implants. Group I consisted of patients presenting for treatment of a dental emergency (general population group), and group II consisted of patients presenting for an implant consultation. The χ2 test was used to determine whether there were differences in knowledge and information sources between the 2 groups. RESULTS: A total of 126 adult patients (76 dental emergency patients and 50 implant consultation patients) participated in the study. The general population group was less informed about dental implants, especially information relating to implant material and longevity, and received information from less reliable sources than patients presenting for implant screening (friends or relatives vs primary dentist). Both groups reported cost of the procedure as a primary barrier to receiving implants (89% and 90%). CONCLUSIONS: There is still a need for continued education of the general public regarding dental implants.

How Effective Is the Tent Screw Pole Technique Compared to Other Forms of Horizontal Ridge Augmentation?

PURPOSE: The tent screw pole technique is one of the methods available for practitioners to perform horizontal ridge augmentation to facilitate dental implant placement. The purpose of this study was to evaluate the efficacy of the tent screw pole technique for horizontal ridge augmentation and to compare the results with those of the tunnel technique and open ridge augmentation. PATIENTS AND METHODS: In this retrospective cohort study, 35 patients underwent horizontal ridge augmentation with the tent screw pole technique, a 1:1 ratio of mineralized freeze-dried bone allograft and particulate bovine hydroxyapatite, and a resorbable collagen membrane. The incidence of early wound dehiscence and membrane exposure, the number of courses of antibiotics and postoperative visits required for their management, and the number of sites that subsequently had successful implant placement were recorded. These parameters were compared with those in 21 patients who had undergone horizontal ridge augmentation by the tunnel technique and 31 patients who had been treated using an open procedure and a resorbable polytetrafluoroethylene (PTFE) membrane in the authors' previous study (J Oral Maxillofac Surg 74:1752, 2016). RESULTS: Implant placement rate was similar for all 3 methods (71 to 97%). However, there were significant differences among the 3 surgical techniques for membrane exposure and wound dehiscence (P = .0033), graft loss (P = .0256), courses of antibiotics (P = .0017), and postoperative visits (P = .0043). The PTFE method consistently had the highest rate of complications, whereas the tent screw and tunnel techniques were comparable. CONCLUSIONS: All 3 techniques allowed a high rate of implant placement; however, the PTFE technique was consistently associated with increased postoperative complications compared with the other 2 methods. The tent screw technique might be more favorable than the tunnel technique in cases in which the bony deficiency is flat.

Is the Tunnel Technique More Effective Than Open Augmentation With a Titanium-Reinforced Polytetrafluoroethylene Membrane for Horizontal Ridge Augmentation?

PURPOSE: Studies have shown that horizontal ridge augmentation with a nonresorbable membrane is subject to a relatively frequent occurrence of dehiscence and loss of the graft. This study was designed to compare the outcomes of a tunnel technique versus an open technique using a titanium-reinforced polytetrafluoroethylene (PTFE) membrane. MATERIALS AND METHODS: A retrospective cohort study, in which the data were collected by chart review, was designed to compare patients who had undergone horizontal ridge augmentation with a 1:1 ratio of mineralized freeze-dried allograft and particulate bovine hydroxyapatite by the tunnel technique with patients who had undergone an open technique with a titanium-reinforced PTFE membrane. The incidence of wound dehiscence or membrane exposure, the number of postoperative visits required, and the number of systemic antibiotic courses needed, as well as the number of grafted sites that subsequently were amenable to routine implant placement after graft maturation, were compared between the 2 techniques. The differences in implants placed between the 2 methods were analyzed with the Fisher exact test. The secondary hypothesis (regarding wound dehiscence, number of postoperative visits, and number of systemic antibiotic courses) was analyzed by Poisson regression. RESULTS: The chart review found 52 patients, with 21 treated by the tunnel technique and 31 treated with the open technique. Within 6 months after bone grafting, 18 patients (86%) treated with tunnel technique grafts received dental implants whereas 22 patients (71%) treated with the open technique received dental implants. Dehiscence developed in a greater proportion of ridge augmentations with the PTFE method (52% vs 19%). There was a trend toward an increased number of courses of antibiotics prescribed for this group (P = .11), as well as a significant increase in the number of postoperative visits required (P = .003). CONCLUSIONS: For horizontal defects amenable to either technique, the findings of this study show the tunnel technique is a more cost-effective option with similar success to the open technique.

Use of Transalveolar Sutures in Conjunction With Grafting to Preserve Vestibular Depth and Augment Gingival Thickness Around Mandibular Implants.

Preservation or reconstruction of the soft tissues around dental implants is an essential component of implant dentistry. Increased width and thickness of the keratinized tissue surrounding dental implants has been recognized as an important factor associated with long-term implant success. When extractions and ridge reduction are performed concurrently with implant placement, maintaining vestibular depth also is of utmost importance. A previous report described a technique for applying bone-anchoring sutures to preserve keratinized tissue and vestibular depth around implants. The present report describes a variation of the procedure for the simultaneous correction of situations in which the existing keratinized tissue is thin and narrow and preserving and apically positioning it might not provide an appropriate gingival cuff.

Use of transalveolar sutures to maintain vestibular depth and manipulate keratinized tissue following alveolar ridge reduction and implant placement for mandibular prosthesis.

Reconstruction of the totally edentulous patient with dental implants has become routine treatment with predictable outcomes. Firm keratinized tissue surrounding the implants and adequate vestibular depth are among the determining factors for long-term implant success. In the staged approach of mandibular implant reconstruction, adequate vestibular depth and attached gingiva surrounding the implants can be readily established at the time of implant placement or when the implants are uncovered. However, when extractions and necessary mandibular ridge reduction to create adequate width are performed immediately before implant placement, maintaining adequate keratinized tissue around the implants and preventing prolapse of the vestibule can present a challenging situation. This report presents a technique that allows the surgeon to stabilize vestibular depth and at the same time position the flaps around the implants and preserve the attached gingiva.

Effect of guided implant placement learning experiences on freehand skills: A pilot study.

OBJECTIVES: Guided implant systems can be used as a training approach for placing implants. This in vitro prospective randomized pilot study evaluated the learning progression and skill development in freehand placement of two implants supporting a three-unit fixed prosthesis on a simulation model among novice operators. MATERIAL AND METHODS: Four senior dental students with no prior implant placement experience participated in the study. As a baseline, each student placed two mandibular and two maxillary implants by freehand technique on a simulation model. Sixteen consecutive guided placements using a static guide, dynamic navigation, and template-based guide followed totaling 32 guided implant placements into maxillary and mandibular models. Freehand implant placements before and after the various guided navigation attempts were compared to assess their impact on freehand skill. Metrics compared included surgical time, horizontal, vertical, and angulation discrepancies between the planned and placed implant positions measured on superimposed CBCT scans and analyzed with repeated measures regression with Tukey's adjusted pairwise comparisons (α = .05). RESULTS: Before training with guided techniques, the average baseline freehand implant placement took 10.2 min and decreased to 8.2 after training but this difference was not statistically significant (p = .1670) There was marginal evidence of a significant difference in the 3D apex deviation with an average improvement of 0.89 mm (95% CI: -0.38, 2.16, p = .1120); and marginal evidence of a significant improvement in the overall angle with an average improvement of 3.74° (95% CI: -1.00, 8.48, p = .0869) between baseline and final freehand placement attempts. CONCLUSIONS: Within the limitations of this pilot study, guided implant placement experiences did not significantly benefit or hinder freehand placement skills. Dental students should be exposed to various placement techniques to prepare them for clinical practice and allow them to make informed decisions on the best technique based on their skills and a given clinical scenario.