Cement-Retained Implant Research Articles

A conservative approach to localize loose implant screw through cemented crown: an in vitro experimental study

BackgroundRetrieval of cement-retained implant-supported restorations is intriguing in cases of screw loosening. Detecting the estimated size of the screw access hole (SAH) could decrease destruction to the prosthesis and preserve the crown.ObjectivesTo precisely localize loose implant screws through cemented crowns to reduce crown damage after screw loosening.Materials and methodsIn this in vitro study, 60 cement-retained implants supported 30 zirconia-based, and 30 ceramics fused to metal (CFM) lower molar crowns were invented, and each was subdivided into three subgroups (10 each). In group I (AI/BI) (control), SAH was created with the aid of orthopantomography (OPG). In contrast, in group II (zirconia-crown), SAH was created with the aid of CBCT + 3D printed surgical guide with a 2 mm metal sleeve in subgroups IIA/IIIA and CBCT + MAR was used to develop SAH in subgroups IIB/IIIB. SEM and Micro-CT scanned the SAH openings to determine the diameter of the hole, cracking, chipping, and chipping volume.ResultsRegarding the effect of plane CBCT and CBCT + MAR on prepared crowns, a highly significant association between group I with group II (p = 0.001) and group III (p = 0.002) was detected. Regarding the cracking of SAH, significant differences between the zirconium crown and CFM restoration (p = 0.009) were found, while for the chipping, no significant association was seen between groups (p = 0.19).ConclusionsCBCT, either as a plane CBCT or with MAR, significantly improved the accuracy of drilling the screw channel and decreased injury to the existing restoration and abutment, aiding in better localization of SAH in loosened implant abutment screws.

Levels of interleukin 1-beta and soluble urokinase plasminogen activation factor in peri-implant sulcular fluid of cement- and screw-retained dental implants.

The present study compares interleukin 1-beta (IL-1β) and soluble urokinase plasminogen activation factor receptor (suPAR) levels in periimplant sulcular fluid (PISF) of patients with cement-retained (CR) and screw-retained (SR) implants. Patients with CR and SR implants were encompassed. Demographic data was collected and implant-related characteristics (geometry, insertion torque, loading and retention protocol, jaw location, duration in function and depth of insertion) were retrieved from records. Modified plaque index (mPI), crestal bone loss (CBL) probing depth (PD) and modified bleeding index (mBI) were measured. suPAR and IL-1β levels were assessed in PISF. Statistical comparisons were done and correlation between clinicoradiographic parameters and PISF IL-1β and suPAR were assessed. P<0.05 were judged statistically significant. Clinical and radiographic parameters showed no difference among SR and CR implants. There was no difference PISF volume among patients with CR (0.22±0.004 μl) and screw-retained (0.19±0.005 μl) implants. Levels of IL-1β and suPAR in patients with CR and SR implants were 50.08±0.6 ng/ml and 44.6±0.08 ng/ml, and 0.28±0.05 ng/ml and 0.22±0.006 ng/ml, respectively. Implants with CR or SR restorations are comparable to one another in terms of clinico-radiographic status and demonstrate IL-1β and suPAR levels within the normal range in the PISF provided oral hygiene is stringently maintained.

Evaluation of Effect of Screw Access Filling Materials on the Retention of Cement-Retained Implant Supported Crowns with Surface Modified Abutments – An In Vitro Study

Background Inadequate data regarding advantages of screw access filling materials and its interaction with the luting agent for improving retention in clinical scenarios with minimal abutment height.Objectives To evaluate the effect of three different screw access filling materials on the retention of cement-retained implant supported crowns with sandblasted abutments when zinc phosphate is used as the luting agent.Methods Thirty Bioline straight dental implant abutments sandblasted and reduced to a height of 5 mm were attached to their corresponding analogs. Thirty Direct Metal Laser Sintering DMLS copings were fabricated. The samples were divided into three groups of ten each and filled with three different screw access filling materials Group A ndash Composite Resin Group B - Cavit and Group C ndash Teflon Tape. All the copings were cemented with zinc phosphate and stored in artificial saliva for 14 days at 37degC. Tensile testing was done in a universal testing machine at a cross-head speed of 5 mmmin. The data collected was subjected to One-way ANOVA test to determine the difference between groups.Results Although the mean uniaxial retentive force was found to be highest for Group B 804 N followed by Group A 690 N and Group C 668 N the results of the One-way ANOVA test showed no statistically significant difference in uniaxial retentive force between the three groups.Conclusion The retention of cement-retained implant supported crowns may not be affected by the screw access filling materials when zinc phosphate is used as the luting agent on sandblasted abutments.

A Systematic Review of Cementation Techniques to Minimize Cement Excess in Cement-Retained Implant Restorations.

Background: The most used types of retention of implant-supported prostheses are screw-retained or cement-retained restorations. The advantages and disadvantages of both have been identified by various authors over the years. However, cement-retained implant crowns and fixed partial dentures are among the most used types of restorations in implant prostheses, due to their aesthetic and clinical advantages. When cemented prostheses are made on implants, the problem of cement residues is important and often associated with biological implant pathologies. The objective of this research was to establish to what extent the techniques to reduce excess cement really affect the volume of cement residues. Materials and Methods: This review was written following the PRISMA statement; a detailed search was carried out in three different electronic databases—PubMed, Scopus, and Cochrane Library. The inclusion criteria were prospective clinical studies, with at least 10 participants per group, and with at least 6 months of the follow-up period. Results: There have been many proposals for techniques supposed to reduce the amount of excess cement in the peri-implant sulcus and on the prosthetic components, but of these, which are exceptional in their in vitro capabilities, very few have been clinically validated, and this represents the real limitation and a great lack of knowledge regarding this topic. Three articles met the inclusion criteria, which were analyzed and compared, to obtain the information necessary for the purposes of the systematic review. Discussion: Extraoral cementation can reduce the excess cement, which, after a normal excess removal procedure, is, nevertheless, of such size that it does not affect the possibility of peri-implant pathologies developing. All these studies concluded that a small amount of cement residue is found in the gingival sulcus, and using eugenol-free oxide cements, the residues were only deposited on the metal surfaces, with a better peri-implant tissues health. Conclusion: Despite the limitations of this study, it was possible to carefully analyze these characteristics and obtain valuable suggestions for daily clinical practice. Resinous cements are considered, due to the free monomers present in them, toxic for the soft tissues. The provisional zinc-oxide cements, also eugenol-free, represent the ideal choice. The different grades of retentive forces provided by these cements do not seem to have clinical effects on the decementation of restorations.

How to Find Abutment Screw Channel of a Cement-retained Implant Supported Restoration? A Literature Reviews

Introduction: Screw loosening is the most common technical complication in cement-retained dental implants. To retrieve screw loosened dental abutment, making abutment screw channel (ASC) is a useful method to access the abutment screw. This article reviews the methods for preparing ASC of cement-retained implant supported restoration. Materials and Methods: The search was conducted on PubMed, Google Scholar, and Scopus. The keywords were screw loosening, cement-retained implant restoration, screw access hole, abutment screw channel and retrieving. Results: Having applied the inclusion and exclusion criterion, 24 articles, 21 technical notes, 1 case report, and 2 reviews were found. Conclusion: The techniques reviewed were categorized into 3 groups of marking techniques, customized guides, and imaging techniques with different outcomes.

Clinical study on screw loosening in dental implant prostheses: a 6-year retrospective study.

ObjectivesIn this study, we determined the incidence and pattern of screw loosening in patients who received dental implants.Materials and MethodsPatients who received implants between January 2008 and October 2013 and completed their prosthetic rehabilitation were evaluated for the incidence, frequency, and onset of screw loosening using dental charts and radiographs. The association between each factor and screw loosening was analyzed using the chi-square test and a multivariate analysis with binary logistic regression models (P<0.05).ResultsTotal 1,928 implants were placed in 837 patients (448 males, 389 females), whose follow-up period after loading varied from 0.25 to 70 months (mean period, 31.5 months). Screw loosening occurred in 7.2% of implants. Most cases occurred less than six months after loading. Among those, 22.3% experienced recurrent screw loosening. Screw loosening was most common in the molar region (8.5%) and frequently associated with an implant diameter of ≥5 mm (14.2%). External implant–abutment connections (8.9%) and screw-retained implant prostheses (10.1%) showed higher incidence of problems than internal implant–abutment connections and cement-retained implants, respectively. Screw loosening was most common in implant prostheses with single crowns (14.0%).ConclusionWithin the limits of the current study, we conclude that the incidence of screw loosening differs significantly according to the position of implant placement, the type of implant and manufacturer, implant diameter, the type of implant–abutment connection, the type of retention in the implant prosthesis, and the type of implant prosthesis.

Complication rates for various retention types in anterior implant-supported prostheses: A retrospective clinical study

Statement of problemImplant-supported prostheses have typically been retained by cement or screws, each of which has advantages and disadvantages. Two new types of prosthesis with complementary advantages and disadvantages have been proposed: the screw- and cement-retained prosthesis, which combines cement and screw retention, and the antiloosening inner-post screw (ALIPS) type, which uses lateral screws. Both esthetic and functional factors should be considered for anterior prostheses; however, clinical studies of the complication rates of these designs are lacking. PurposeThe purpose of this retrospective clinical study was to evaluate the complications of dental implant-supported restorations with various prosthetic types in the anterior region and to analyze other factors that affect complications. Material and methodsThis study included 51 patients who had 83 implants placed in the anterior region by a single clinician between August 2009 and December 2016. Surgical and prosthetic features were recorded, and implant complications were analyzed. ResultsThere were 45 (55.4%) cement-retained implants, 5 (6.0%) screw- and cement-retained prosthesis implants, and 32 (38.6%) ALIPS-retained implants. Peri-implant mucositis was observed most frequently in the ALIPS type (21.9%), but the biological complications did not differ significantly with the prosthetic type. The most common mechanical complication was loss of retention in the cement type of prosthesis (30.4%) and screw loosening in the ALIPS type (43.8%). Implant complications varied with position (maxilla or mandible) and implantation timing (period from tooth extraction to implant placement). ConclusionsThe complications of implants placed in the anterior region were affected by different factors but did not differ significantly with the type of the retention.

Preventing Peri-implantitis with a proper Cementation Protocol and with the consideration of alternatives to Cement-Retained Implant Restorations

Preventing Peri-implantitis with a proper Cementation Protocol and with the consideration of alternatives to Cement-Retained Implant Restorations

Zinc phosphate as a definitive cement for implant-supported crowns and fixed dentures.

Implant-supported dental prostheses can be retained by a screw or cement. Implant-supported fixed partial dentures have a passive fit. A passive fit means there is an internal gap between the abutment surface and the intaglio of the retainer to insure that there is no lateral pressure on the supporting implants or friction upon seating of the prosthesis. This gap is filled with cement for retention of the prosthesis. Any lateral pressure may cause marginal bone loss or periimplantitis. Also, there is usually a microscopic gap at the margin of a crown retainer that exposes the cement to oral fluids. The solubility of zinc phosphate (ZOP) cement is a definite liability due to the risk for cement dissolution. In fixed prostheses, the dissolution of the cement of one or more retainers would cause a transfer of the occlusal load to the retained unit(s). The resulting rotation and lifting of the cement-retained implants from occlusal and parafunctional loads could cause loss of osseointegration of the abutment-retained implant(s). ZOP cement may not be indicated for implant-supported fixed partial dentures or splints. Cement dissolution in single unit probably only involves re-cementation, if the patient does not swallow or aspirate the crown.

Fabricating a Versatile Cement-Retained Implant Provisional Restoration with a Customized Temporary Abutment

Fabricating a Versatile Cement-Retained Implant Provisional Restoration with a Customized Temporary Abutment

Survey of Screw-Retained versus Cement-Retained Implant Restorations in Saudi Arabia.

Introduction Implant-supported prostheses are currently the standard treatment for the replacement of missing teeth and deficiencies. Implant restorations can either be screw-retained, cement-retained, or both. The implant retention system type is typically chosen during the treatment plan. The primary purpose of this study is to investigate the frequency of implant restoration retention systems. Materials and Methods A five-page questionnaire was sent to private institutes, educational institutes, and governmental hospitals that provide dental services. The data were analyzed using descriptive statistics. Results Prior to distribution, the surveys were proofread and pilot-tested at the Faculty of Dentistry at Umm Al-Qura University. The surveys were mailed to three groups: private institutes, educational institutes, and governmental hospitals. In total, 120 surveys were distributed and 87 surveys were returned, for a response rate of 73%. This included thirty-six surveys (41.4%) from private institutes, twenty-two surveys (25.3%) from educational institutes, and twenty-nine surveys (33.3%) from governmental hospitals. Conclusions In general, Astra was cited as the most widely used implant system. In addition, cement-retained restorations were more frequently used than screw-retained restorations. However, dental implant failure was more frequently associated with cement-retained restorations than with screw-retained restorations.

Effect of Preseating, Screw Access Opening, and Vent Holes on Extrusion of Excess Cement at the Crown-Abutment Margin and Associated Tensile Force for Cement-Retained Implant Restorations.

This study sought to (1) compare the effects of crown preseating prior to cementation, (2) determine whether maintenance of screw access openings on titanium abutments and open vent holes on cast crowns affects the amount of excess cement at the crown-abutment margin, and (3) analyze the associated tensile force after cementation. Three independent variables were tested: (1) abutment screw access (open or closed), (2) crown coping modification (with or without a vent hole in the palatal aspect), and (3) crown preseating on an abutment analog. Ten implant crown copings were cemented using temporary cement on ten straight implant abutments for each combination of the three independent variables. The amount of excess cement at the crown margins was measured by weight. Axial tensile load was measured 24 hours after cementation. Results were statistically analyzed using linear regression and univariate three-way analysis of variance (α = .05). Open screw access, presence of a vent hole on the crown, and preseating of the crown had significant effects on the amount of excess cement at the crown margin (P < .05). Preseating significantly lowered tensile strength values (P = .001), particularly in specimens with preseating and open screw access (P < .001). There was no significant correlation between excess cement at the margins and tensile strength values. Placement of vent holes on the crown or open screw access may be considered for cementing crowns on implant abutments using temporary cement in order to minimize excess cement at the crown margin. A preseating protocol is not advisable, either alone or combined with open screw access, since it significantly reduces the retentive strength of cemented restorations (P < .001).

Influence of Screw Access Channel on All Ceramic Cement-Retained Implant Supported Posterior Crowns

Influence of Screw Access Channel on All Ceramic Cement-Retained Implant Supported Posterior Crowns

Effect of Preseating on the Extrusion of Excess Cement at the Crown- Abutment Margin and the Associated Tensile Force for Cement-Retained Implant Restorations. A Pilot Study

The purpose of this study was to compare the effect of preseating prior to cementation on the amount of cement excess at the crown-abutment margin and to analyze the associated tensile force after cementation. Preseating of the crown on an abutment analog was evaluated. Ten implant copings were cemented with temporary cement on ten straight implant abutments. The amount of cement excess at the crown margins was measured by weight. Axial tensile force was measured 24 hours after the cementation. Results were statistically analyzed using ANOVA (p= 0.05). Preseating of the crown had a significant effect on the amount of cement excess at the crown margin (p&lt;0.05), without lowering the tensile strength values significantly. When cementing crowns on implant abutments with temporary cement a preseating protocol might be advisable in order to reduce the amount of cement excess at the crown margin.

An Insight into Different Innovative Techniques to Retrieve Cement-retained Implant Supported Prosthesis

An Insight into Different Innovative Techniques to Retrieve Cement-retained Implant Supported Prosthesis

Strain Comparisons for Splinted and Nonsplinted Cement-Retained Implant Crowns

The aim of this study was to compare strains generated by splinted and nonsplinted cement-retained implant crowns for two implants. A stereolithic resin cast was printed using computed tomography scan data from a patient. Two 4 × 6-mm implants were placed in the posterior left side of the cast. Splinted and nonsplinted cement retained crowns were made. The three-dimensional image correlation technique was used for the measurement of strains as crowns were loaded up to 400 N in vertical and oblique directions with an Instron machine. Patterns and magnitudes of strain for splinted and nonsplinted crowns were similar. Results of this in vitro study suggest that splinting has a minimal effect on the load sharing of adjacent cement retained crowns.

Effect of Misfit of Cement-Retained Implant Single Crowns on Crestal Bone Changes

The purpose of this clinical study was to compare peri-implant crestal bone levels between misfitting (overhanging/open margin) cement-retained implant single crowns (SCs) vs accurately fitted implant SCs. Seventeen subjects were divided into two groups: test group (misfitting crowns, n = 10) and control group (accurately fitted crowns, n = 7). Crestal bone level changes were assessed using digital software. The average differences in mean bone loss within and between the two groups were statistically significant. Cement-retained implant SCs with marginal misfit resulted in more crestal bone loss than accurately fitted crowns after a mean of 3 years in function.

In Vitro Radiographic Detection of Cement Overhangs on Cement-Retained Implant Restorations

The aim of this in vitro study was to investigate the potential of digital and conventional radiography to detect small amounts of residual dental luting cements around implant abutments. Artificial cement and aluminum overhangs in varying thicknesses, heights, and depths were radiographed adjacent to implant restorations with a radiovisiography sensor. Five trained evaluators were asked to identify the smallest depth of overhang that could be detected on radiographs. For detection of cement overhangs adjacent to implant abutments, a luting agent must have greater radiopacity than what is recommended by relevant International Organization for Standardization directives. To detect a 0.1-mm-thick portion of excess cement adjacent to an implant abutment, the cement should have a radiopacity of at least 1.7 mm of aluminum for high-resolution digital radiographs and 2.2 mm of aluminum for film-based radiographs. Two-way analysis of variance revealed that the thickness of the specimens, type of imaging detector, and type of cement all affected the radiopacity threshold for artificial cement excess (P < .05). The height of the specimens and the surrounding structures were not statistically significant factors in cement detection. Digital radiography offers better possibilities for visualization of cement excess than conventional radiography.

A Technique for Repairing a Loosening Abutment Screw for a Cement-Retained Implant Prosthesis

Prostheses may be attached to implants or implant abutments using screw retention or cementation. With the increased use of cement-retained, implant-supported restorations for the replacement of missing teeth, clinicians may choose to use a definitive cement to lute the definitive restoration. Loosening of an abutment screw is a challenging complication of cement-retained, implant-supported prosthetic restorations. Often, the abutment screw becomes loose from the implant body, whereas the crown remains cemented to the abutment. In such situations, separating the cemented crown from the underlying abutment or locating the abutment-screw access for removal of the restoration is a difficult task. The purpose of this report is to describe a simple technique for locating the abutment-screw access in the event of its loosening. The advantage of this technique is that it can facilitate easy location of the abutment screw, thus minimizing damage to the existing restoration and allowing it to be reused.

A Modified Plastic Shell Technique for Cement-Retained Implant Restorations

The best possible fit of prosthetic components should be the aim of the clinician. The technical report presented here describes the use of a modified plastic shell technique for modeling a cement-retained single-implant restoration. This approach will help to prevent potential errors caused by the wax modeling technique.