Excess Cement Research Articles

Technical Notes and Tips: Use of a Dental Tool to Remove Excess Cement in Unicompartmental Knee Arthroplasty

Technical Notes and Tips: Use of a Dental Tool to Remove Excess Cement in Unicompartmental Knee Arthroplasty

Use of a Dental Tool to Remove Excess Cement in Unicompartmental Knee Arthroplasty

Use of a Dental Tool to Remove Excess Cement in Unicompartmental Knee Arthroplasty

An Analysis of the Effect of a Vent Hole on Excess Cement Expressed at the Crown–Abutment Margin for Cement‐Retained Implant Crowns

The labial margins of anterior implant-retained crowns are often positioned subgingivally for a superior esthetic appearance. One of the consequences of subgingival margins is the increased risk of leaving excess cement behind following cementation. This can lead to potential problems, including peri-implant inflammation, soft tissue swelling, soreness, bleeding or suppuration on probing, and bone loss. The purpose of this laboratory study was to investigate the effect of placement, location, and diameter of a vent hole on the amount of cement being expressed at the margin of an anterior implant abutment-retained crown. Three implant crown copings were fabricated to fit on the same custom abutment. Three vent diameters (0.75, 1.25, and 1.65 mm) and three locations on the palatal surface of the coping (cervico-palatally, mid-palatally, inciso-palatally) were chosen for vent hole placement. For each test, the coping was cemented onto the abutment under standardized conditions. A preweighed thin coating of cement was applied to the fit surface of the coping. The amount of cement expressed at the margin and vent hole was measured by weight and calculated as a proportion of the amount of cement placed in the coping before seating. The procedure was completed 15 times for each variable. The results were statistically analyzed using univariate ANOVA with post hoc Bonferroni-adjusted independent samples t-tests. The presence of a vent hole influenced the proportion of cement expressed at the coping margin (p < 0.05). The location of a vent hole influenced the proportion of cement expressed at the coping margin (p < 0.05), with the exception of the mid-palatal and inciso-palatal positioning where there was no significant difference (p= 0.61) between groups. The diameter of the vent hole did not significantly influence the proportion of cement expressed at the coping margin (p= 0.096). When using anterior cement-retained implant crowns, the use of a 0.75-mm mid-palatal or inciso-palatal vent hole to minimize the amount of cement expressed at the margin during cementation should be considered.

Free bone cement fragments after minimally invasive unicompartmental knee arthroplasty: an underappreciated problem

The minimally invasive implantation of unicompartmental knee arthroplasty (UKA) leads to excellent functional results, but due to the reduced intraoperative visibility the removal of excessive cement may be difficult. In a retrospective study we assessed radiologically the incidence of loose and excess bone cement in 120 UKAs and correlated it to the thickness of the tibial cement layer. In 25 cases loose or attached excess cement was seen. Two of these patients with loose cement bodies required revision surgery. An additional 2 patients not operated at our institution required revision because of pain and loss of motion. The average thickness of the tibial cement layer was 3.1 (1.7-5.0) mm in all the patients. But it was significantly higher in the group with excess cement bodies [3.3 (2.3-5.0) mm] compared to the group without excess cement [3.0 (1.7-4.1) mm] (P < 0.05). Symptomatic free cement bodies need to be removed immediately, if necessary arthroscopically, in order to avoid damage to the implants. To avoid this problem in minimally invasive UKA, intraoperative fluoroscopy, a dental mirror or a nerve hook seem to be useful tools to identify and remove loose or excess cement.

The Rationale for the Vented-crown Technique and Its Application in Today's Dental Practice

It would be safe to assume that the integrity of a full coverage restoration is directly related to its marginal fit. Complete, unimpaired seating of a full coverage restoration can be significantly affected by hydraulic pressure from the cement.1–2 Hydraulic pressure, created by seating a restoration, especially a well-fitting one, can result in a final marginal gap that is clinically unacceptable. Incomplete seating due to hydraulic pressure is a greater problem with posterior teeth. The large, flat occlusal surface of this type of preparation creates a large well or platform for cement to pool and prevent seating. Also, preparations with long, parallel walls and a large occlusal surface are even more of a concern. Anterior preparations tend to be more conical in shape and have no or minimal occlusal table. They may be less affected with the problem of hydraulic pressure.3Improving the marginal fit of restorations can help to prevent the problems of open margins, cement washout, recurrent decay, poor gingival health and disrupted occlusion. The seating of a full coverage restoration can be improved significantly by using external venting,1–24–6 a die spacer7–9 and internal venting.310–12 When the literature is consulted, it is consistently found that, when no relief is used, the marginal gap can vary from 200–100 μ, based on the theory of hydraulic pressure.1–610–14 Using a die spacer will reduce the marginal gap to 60 μ.13–14 The best seating, close to 20 μ, was achieved when an external vent with die spacer was used.1–24–6 Different cement types do not seem to play a significant role in the marginal fit if a die spacer and external venting are used.13–15 Marginal design also does not seem to affect marginal fit, if a die spacer and/or vents are used.16 Actually, the better the casting fits at the margin, the more there is need for relief during seating, because hydraulic pressure has the potential to be a greater problem. An oversized, poor fitting casting cannot build-up as much hydraulic pressure.Venting to reduce internal hydraulic pressure may also have additional benefits with porcelain fused-to-metal crowns. Research indicates that internal hydraulic pressure can deform a crown and possibly contribute to premature porcelain fractures.17–18 The escape provided by the vent is a great way to reduce these internal hydraulic pressures and the potential for lateral deformation during seating.The use of a single internal vent channel placed on the wall of a preparation has also been shown to improve the seating of a full coverage restoration.310–12 The escape channel needs to be placed as close as possible to the margin and facilitate the release of excess cement. If the escape channel is under extended, in the range of 2 mm or greater from the margin, the benefit of this technique is lost. This technique has shown results in the 40–50 μ range for marginal gap sizes. It is a simpler technique and does not require a vent hole to be repaired.The goal of obtaining the best marginal fit seems to lie with using the die spacer and an external vent. The ease of using a die spacer alone will provide consistent margins of 60 μ, which may very well be clinically acceptable. However, when the extra step is taken with an external vent, the following benefits are achieved:This article reviews a simplified external venting technique first described by Basset2 and later by Seberg.22 This technique will be extrapolated to porcelain fused-to-metal crowns. The technique demonstrates a simple, yet effective, way to seal the external vent hole. Once the vent hole is sealed with a gold pin and polished, it is practically invisible. An example will also be shown and briefly discussed with a case using an internal vent.Special thanks go to my lab support: Penny Marazzo, Stoneybrook Noble Gold, 242 Stoneybrook Rd, Newtown, PA 18990, USA, (215) 860–3936 and Art Nelson, Bjorn Dental Lab, 16 Polly Drummond Hill Rd, Suite 7, Newark, DE 19711, USA, (302) 454-8245.

Immediate Maxillary Lateral Incisor Implants with Nonocclusal Loading Provisional Crowns

This clinical report series describes a treatment modality involving immediately placed dental implants in maxillary lateral incisor sites using noncemented immediate provisional crowns retained with calcinable copings (prosthetic complement used in preparing the metal for the definitive prosthesis). Ten implants were placed in eight patients for the replacement of maxillary lateral incisors: two immediate and eight corresponding to cases of agenesis. All were subjected to immediate rehabilitation with provisional acrylic resin crowns in nonocclusal loading. One implant failed 3 weeks after placement due to acute local trauma. The other nine remained functional within the mouth, with normal clinical and radiological characteristics after a minimum of 12-month follow-up. Immediate placement of implant fixed provisional restorations retained by friction in maxillary lateral incisors offers an esthetic solution, eliminates the need for a removable provisional restoration, and avoids implant failures associated with excess cement or screw loosening. Moreover, in the case of extractions, immediate placement and provisionalization of implants in maxillary lateral incisors can effectively optimize the peri-implant esthetic results by maintaining the existing hard and soft tissue architecture of the replaced tooth. As no cement or screws are required, and the provisional crowns are placed in nonocclusal loading, the risk of complications is minimized.

Die Spacer가 도포된 보철용 크라운과 어버트먼트의 계면현상

Fit of the restoration and its cementation procedure is crucial to both its short and long term prognosis. Marginal fit is affected by many variables during the fabrication process. These variables, being intrinsic properties of the materials or the clinical technique used, can cause changes in the size and shape of the definitive restoration. Even if all variables are controlled carefully, the seating of a restoration can still be affected due to insufficient space for the luting agent. The use of die spacer can reduce the elevation of a cast restoration of a prepared tooth, decreased seating time, improve the outflow of excess cement, and lower the seating forces. The purpose of this study was to evaluate the marginal fidelity according to die spacer application times and measurement site. Casting alloys were prepared and fabricated using non-precious metal at <TEX>$950^{\circ}C$</TEX>. Specimens are divided into four groups: I(die spacer painted casting for wax pattern), II(die spacer non painted casting for wax pattern). The specimens were cut and polished for marginal gap observation. The marginal gap was observed using scanning electron microscopy (SEM).

Removing Excess Bone Cement

Removing Excess Bone Cement

Methods of Removing Excess Bone Cement

Methods of Removing Excess Bone Cement

Optimizing resin cement removal around esthetic crown margins

Objective. To quantify luting cement at the crown–tooth interface of esthetic crowns fabricated using four different techniques and two methods of excess cement removal. Material and Methods. Four methods of crown fabrication were used: the feldspathic porcelain and platinum foil technique, the feldspathic porcelain and refractory die technique, the resin composite crown and CAD/CAM technique, and the feldspathic porcelain crown and CAD/CAM technique. Half of the cemented crowns were allocated to Group A: removal of excess cement by flicking-off with a plastic instrument 3 min after initial polymerization, or Group B: removal of excess cement using a wiping action with cotton pellets. Morphologic measurements, using non-destructive digital profilometry, were made of the volume of excess cement (mm3), mean maximum and mean depth of excess cement (µm), and surface area of excess cement (mm2). Results. ANOVA and Duncan post-hoc tests revealed no statistical differences (p<0.05) between the four types of crown fabrication with respect to volume and mean depth of retained luting cement. There was a significantly greater volume, mean depth, and mean maximum depth of luting cement retained using the “flick off” method compared to the cotton pellet “wiping” method for excess cement removal, but no statistical differences in mean surface area between the two methods. Conclusions. Following removal of excess luting cement, as judged clinically, using two methods, subclinical amounts of cement remained adherent to the tooth surface of all specimens at the crown–tooth interface.

Fabrication of a cement- and screw-retained implant prosthesis

The advantages of cement-retained implant-supported restorations over screw-retained implant restorations are well documented. Difficulty with prosthesis retrieval and excess cement removal may be experienced with cemented restorations. The technique described allows for the fabrication of a retrievable cemented prosthesis that is simple, practical, and effective.

Management of peri-implant bone loss using guided bone regeneration: a clinical report

This clinical report presents a patient who developed peri-implant bone loss around 2 maxillary endosseous root-form implants after restoration with cement-retained single crowns. Significant localized bone loss occurred around 1 of the implants due to retained excess cement. Reparative treatment consisted of a guided bone regeneration technique. Following a 9-month period of submerged healing, the implants were re-exposed and restored to complete function.

Extraarticular abrasive wear in cemented and cementless total knee arthroplasty.

In this study, we examine the contributions of periprosthetic impingement to a seldom recognized source of PE damage resulting in gouging, abrasion, and severe localized damage in cemented and cementless total knee replacement. One hundred sixty two tibial components of 34 different designs in a retrieval collection were examined. The presence and location of abrasive wear to the nonarticulating edges of the insert were measured, with representative specimens examined using SEM. Significant abrasive wear was observed in 35% of the retrievals with cemented femoral components and 25% from noncemented components. Within the group of worn inserts, abrasive scars were seen with a frequency of 75% on the extreme medial edge, 20% on the extreme lateral edge, 26% on the posteromedial edge, and 16% on the posterolateral edge. The role of extraarticular impingement in this damage mode was confirmed by examination of retrieved femoral components with overhanging cement or embedded osteophytes. In the majority of cases, this complication may be avoided by careful removal of excess cement and extracortical osteophytes.

Controlling Cement Tops Through Use of Fibre-Based Slurries Reduces Drilling Costs

Abstract When drilling in southern Alberta near the town of Strathmore, operators have historically encountered unpredictable lost circulation during cementing operations on many wells. With the surface casing set above ground water, operators are required to bring cement to surface on all production casings. Costly remedial cement treatments are often required. Openhole logs in the area have shown the presence of numerous coal seams at depths ranging from 20 to 250 m (66 to 820 ft.) below surface. Postcementing temperature logs indicate that the cement top may be found at any one of these coal seams. The presence of the coal seams alone does not, however, appear to definitively indicate the potential for a problem, as evidenced by wells separated by less than a mile that may react completely differently. Currently, there is no way to determine which wells will experience problems so the normal approach has been to bring cement to surface before dropping the top wiper plug and displacing the casing. Unfortunately, this methodology has not proven to be 100% successful, and wells with no losses require the disposal of a significant amount of cement at a substantial cost. Recently, the introduction of specifically sized silicic fibres to the cement blend in conjunction with a revamped cementing procedure has proven to be a cost-effective solution to the problem of low cement tops. This paper will take a look at previous efforts at solving the problem along with alternatives that have been considered and rejected. It also includes data showing the efficacy and economics of the new approach. Introduction Shallow gas drilling in southeastern Alberta poses a unique set of challenges. Because the production rate on shallow gas wells is relatively low and the number of wells required to fully exploit the reserves is quite high, the driving forces behind drilling and completing the wells all revolve around reducing costs and improving efficiency. To put this into perspective, consider the following: the time from spud to rig release is normally less than 24 hours per well. Typical production from a shallow gas well in southeastern Alberta ranges from 50 to 150 mcf/day. In 2001, there were more than 5,000 shallow gas wells drilled in the Western Canadian Sedimentary Basin. One of the challenges that is often encountered in shallow gas drilling is lost circulation while cementing. Lost circulation while cementing creates additional costs in shallow gas drilling in several ways. Low cement tops require top-out cementing and, in some cases, very costly squeeze cementing operations. Cementing programs are often designed with large excess cement volumes in an attempt to achieve cement back to the surface despite losses. When excess cement is returned to surface, it must be disposed of at a substantial cost. Therefore, the ability to predictably eliminate lost circulation while cementing will do away with the cost of top-ups and squeezes, reduce the amount of cement required, and minimize surface disposal costs for cement returned to surface.

A crown venting technique for the cementation of implant-supported crowns

With the increased use of implant systems for the replacement of single teeth, some dental practitioners are choosing to permanently cement the final restoration instead of using the screw-retention modality. Many of these restorations have subgingival margins; therefore, the cementation technique becomes a critical procedure because incomplete seating of the restoration or excess cement can be lodged in the gingival sulcus. The use of a cement escape way or venting technique for the cementation of an implant-supported restoration is described. (J Prosthet Dent 2003;89:89-90.)

Techniques to minimize excess luting agent in cement-retained implant restorations

J Prosthet Dent 2002;87:112-14.

骨移植を併用した人工膝関節置換術

Eleven knees with bone grafts for tibial defects at the time of primary total knee arthroplasty were followed up for six to twenty-eight months. All patients achieved full weight bearing within two days after surgery. None of the patients developed apparent loosening of the tibial compornents or collapse of grafting bones. Bone grafting is a viable alternative to using custom tibial components or excess cement for tibial defects.

Selection of materials for post cementation.

Many types of cement are available for post cementation, each with advantages and disadvantages. For posts with adequate mechanical retention, zinc phosphate is a good choice for patients for whom fluoride release is not considered essential. Posts with compromised mechanical retention benefit from use of a resin-modified glass-ionomer cement, which also releases fluoride. Composite resin cements should be reserved for rare cases where mechanical retention is so compromised that use of a resin-modified glass-ionomer cement provides inadequate retention. Great care is required when using composite resin cements to ensure optimum performance and avoid the creation of difficult-to-remove excess cement. Clinicians should be aware that posts cemented with resin-modified glass ionomer or composite resin cements may be difficult or impossible to remove if access to the root canal system is subsequently required.

New method for the in vitro evaluation of dental alloy bonding systems

Statement Of Problem: Bonding systems are used in some fixed prosthetic devices with base alloys. However, different studies of the same dental alloy bonding agents, under similar circumstances, have yielded disparate results in bond strength testing. Purpose: This study compared directly 2 dental alloy bonding systems through a “duel” type of confrontation, which basically is a 2-way tensile force test. Material And Methods: Ninety Wiron 88 base alloy cylinders (diameter of 8 mm length 15 mm) were sandblasted on both sides with Al203 powder (particle size 50 μm) during 10 seconds at an approximate distance of 5 mm, at an air pressure of 60 psi determined before sandblasting procedures. The surface of each cylinder was cleaned from Al203 powder with a strong burst of oil-free air from a chairside air syringe. Thirty cylinders were randomly assigned to 1 of 3 groups for direct bond strength comparison: (1) Panavia 21 to Panavia EX, (2) Panavia 21 to Metabond, or (3) Panavia 21 to a combination of a resin bonding agent plus Panavia 21. Each group was composed of 10 specimens that used 3 cylinders for each specimen. Each side of the sample cylinder received the same quantity of cement and 1 cylinder at a time was bonded to it. Cylinder alignment was verified with a Boley gauge during luting procedures. The bonded 3-piece block was held together for 24 hours under a compressive force of 2 kg/cm2 using a hydraulic press. Excess cement was removed with a brush, and the pertinent air sealant was applied to allow for autocuring of the cement. Specimens were later stored in water at room temperature for 48 hours before thermocycling procedures. Each specimen was thermocycled for 100 cycles with a 5-minute dwelling time in water at 4°C and 60°C. Specimens were subject to tensile force testing until debonding in 1 of the cylinders. Results: The opposing pull duel test (OPDT) showed that the Panavia EX failed (40.3 MPa) 10 of 10 duels against Panavia 21, whereas Panavia 21 failed (49.7 MPa) 9 of 10 duels against Metabond, and Panavia 1 failed (50.1 MPa) 10 of 10 duels against Photobond+Panavia 21. ANOVA revealed significant differences (P <.05) between PAN-EX group and MET and PHB+P21 groups. However, no significant differences were found between MET and PHB+P21 groups. Conclusion: The opposing pull duel test was a valid method to directly compare bond strengths of 2 bonding systems to dental base alloys. There was a small dispersion of the values even though cement mixing and thickness variables were difficult to control. Duel tensile testing provides meaningful information on the superiority of one bonding system over another in this controlled environment. (J Prosthet Dent 2000;84:217-21.)

Retention of adhesive cement on the tooth surface after crown cementation

Statement of problem. Adhesive cements increase crown retention, but it is unknown if traces of cement remain undetected on the tooth surface after clinical removal of excess cement, which could exacerbate plaque retention. Purpose. This study measured the surface area, volume, mean depth, and maximum depth of a resin composite and a compomer luting cement left adherent on the tooth surface after removal of excess cement, as judged clinically. Methods and material. Four groups of specimens (n = 48) were prepared for full coverage crowns: group AC bonding alloy with chamfer finish line, group G gold alloy with chamfer finish line, group PC porcelain with a chamfer finish line, and group PS porcelain with a shoulder finish line. Two profiles of the mesial and distal surfaces of the teeth were carried out: (1) tooth with crown seated but not cemented and (2) tooth with the crown cemented in place. Two cements and 2 methods of cement removal were studied. Results. A 4-way analysis of variance for cement, crown type, method of removal, and tooth surface morphology showed that significantly greater volumes and mean depth, but not surface areas, of resin composite cement remained adherent than compomer cement ( P<.05). Among crown types, significant differences were found for cement volume (group G>AC, G>PC, G>PS), cement surface area (group AC>PC, G>PC, G>PS), and maximum cement depth (group G>AC). There was no significant difference between the 2 methods of cement removal. Significantly larger surface areas and maximum depths of cement were retained on the anatomically grooved mesial surface of the maxillary first premolars than on the ungrooved distal surface. Conclusion. Subclinical cement retention occurred after crown cementation, which was influenced by cement, crown type, and tooth surface morphology but not method of cement removal. (J Prosthet Dent 1999;81:668-77.)