(For Individual Attention Only) Not for distribution in the U. S. Scientific Compendium Xeno V 1

Transcription

1 (For Individual Attention nly) Not for distribution in the U. S. Scientific Compendium Xeno V 1

2 Table of contents 1 Introduction Storage conditions and shelf-life Xeno V Product Description New Chemistry Summary of new chemistry Components and functions In vitro Investigations Adhesion Bond Strength to Dentin and Enamel Micro Shear Fatigue Resistance (µsfr) to dentin Marginal Integrity Marginal Integrity of class V cavities Marginal Integrity of class II cavities Micro Morphology FESEM investigation of etching pattern in enamel and hybrid layer in dentin Clinical Investigations Clinical Class V Studies at the Medical University of Berlin and Bologna University Clinical Class II Study at Freiburg University Conclusion from the results of the clinical studies Directions for Use References Glossar and Abreviations List of Figures List of Tables Scientific Compendium Xeno V 2

3 1 Introduction Adhesive Dentistry has been gaining increasing importance for today s challenges in fulfilling patients needs, and is now used for most direct restorations in restorative dentistry. From the perspective of the patients, it means that in place of amalgam adhesively bonded compomer fillings are used in deciduous teeth, which are state-of-the-art today (Krämer et al., 2007). Furthermore, adhesive minimal invasive restorations are the treatment of choice in permanent dentition, in place of the cavity extension for prevention and the cavity extension needed for mechanical retention. Adhesive technology will also be the key approach for solving the increasing challenges in treatment of elderly patients, who are proud of having their own teeth and prefer direct restorations instead of replacement by indirect approaches. In contrast to traditional procedures such as amalgam fillings or cementation, adhesive technology is more complex and applications steps and techniques depend very much on the product used. Therefore, numerous efforts have been undertaken to reduce complexity and to increase the robustness of both the products and the application steps. ne principal step in reducing complexity is to use self-etching adhesives. Further reduction in complexity is gained by providing a one-component formulation. However, the robustness of these one-component self-etching adhesives with regard to storage conditions is very often neglected. The practitioner can see visible changes in the adhesive as a warning to discontinue use of the adhesive. Use of an adhesive with changes that are not immediately visible may lead to clinical failure. Therefore, a one-component self-etching adhesive that can be stored at room temperature is a major breakthrough in bringing adhesive dentistry one step further. Detailed information about the development of Xeno V can be found in the following chapters. 1.1 Storage conditions and shelf-life In general, polymerizable acrylate monomers are used in an aqueous, acidic solution as this is a requirement for one component self-etching dental adhesives. These monomers have to face two different potential degradation reactions: Scientific Compendium Xeno V 3

4 First, reactive solvent molecules can add at the polymerizable group, which results in the loss of its polymerizable function (Figure 1), although the overall monomer structure is not disrupted. (Figure 1). X R X + ethanol acid X R X Figure 1 Addition of solvent molecules (i.e. ethanol) to polymerizable groups (grey) results in loss of the polymerizable function (open circle) (X = for ester; X = NH for amide) Second, the reaction of water with a polymerizable group does not destroy its function, but separates the polymerizable group from the rest of the monomer by hydrolysis (Figure 2). a) ester linkage of polymerizable group R + H 2 acid H H R b) ester linkage of polymerizable group with phosphoric acid function R P H H + H 2 acid H H R P H H Figure 2 Separation of polymerizable groups (grey) by hydrolysis Both degradation mechanisms result in a reduced density of the polymer network. In the case of functionalized acidic monomers the hydrolysis may lead to acidic components that are no longer polymerized into the network (Figure 2 b). Thus, further etching by these mobile groups could occur at the interface. Formulations in which relevant components are separated by primary packaging with two compartments or in two separate bottles can be stored at room temperature over the respective shelf-life (Table 1). Scientific Compendium Xeno V 4

5 Two-components Storage condition Xeno III 2 24 C Adper Prompt L-Pop 25 C Table 1 Storage conditions of two-component self-etching adhesives However, one-component formulations based on acrylate ester chemistry and traditional solvents, as listed in Table 2, cannot be stored at room temperature for their entire shelf-life. ne-component Storage condition Remarks AdheSE ne 2 28 C Clearfil S3 BND 2 8 C If not in use. G-BND 1 28 C If not in use for a prolonged period of time, store in refrigerator! ibnd Gluma inside 8 C ibnd Self Etch 4 10 C Before first use. Then 23 C. ptibond All in ne 2 8 C Table 2 Storage conditions for one-component self-etching adhesives according to the respective manufacturer instructions To combine ease of use of one-component formulations, self-etching technology, and storage at room temperature for the entire shelf-life new monomers and formulations had to be invented. 2 Xeno V Product Description Xeno V is a one component self-etching dental adhesive designed to bond resin-based, lightcuring direct restorative materials to enamel and dentin. Xeno V does not need to be mixed. Although delivered as one component, it does not need to be stored in a refrigerator. Scientific Compendium Xeno V 5

6 2.1 New Chemistry The high tolerance of Xeno V towards storage conditions of up to 24 C is obtained by using new monomers acryl resins with amide groups instead of ester groups inverse functionalized phosphoric acid esters instead of ester functionalized phosphoric acid esters and the use of tertiary butanol instead of lower molecular weight alcohols, like ethanol, as a solvent The Xeno V components and their functions are given in more detail in Table 3. Their chemical structure is shown in Figure 3 and Figure 5. Component Bifunctional acryl resin with amide functions Acryloylamino alkylsulfonic acid inverse functionalized phosphoric acid ester Acrylic acid Camphorquinone, Coinitiator Butylated benzenediol Water Tert-butanol Function Crosslinker Etchant and wetting aid Etchant, adhesion promoter and wetting aid Wetting aid Photoinitiator system Stabilizes monomers during storage Solvent for the resins and etch promoter Solvent for the resins and mild stabilizer Table 3 Components of Xeno V and their function Scientific Compendium Xeno V 6

7 ethanol propanol n-butanol = = C = H iso-propanol tert-butanol Figure 3 Chemical structure of alcohols In Xeno V tert-butanol is used as the solvent. The alcohol group in tert-butanol is shielded by the surrounding methyl groups of the tertiary group (Figure 3). Therefore tert-butanol is not able to chemically react by addition at the acrylate resins in the same way ethanol and isopropanol do (Figure 4). For this reason formulations containing tert-butanol are chemically more stable than those containing ethanol or iso-propanol. acid R X X + tert-butanol Figure 4 Addition to polymerizable groups does not occur with tert-butanol (X = for ester; X = NH for amide) Scientific Compendium Xeno V 7

8 amides less prone to hydrolyses R' NH NH R NH R' inverse ester less prone to hydrolyses Patent Protection Figure 5 General chemical structures of the key monomers used in Xeno V. R P H highly acidic sulfonic acid group NH H R S H phosphoric acid ester group as known from PENTA H S P H H Xeno V comprises newly developed and patented monomers as schematically described in Figure 5. The novelty is due to the introduction of amide groups and inverse methacrylic ester functions instead of ester functions. Based on their molecular structure, amides are more stable in an aqueous, acidic solvent solution compared to ester. This protective effect is illustrated in Figure 6 and the resulting stability is demonstrated in Figure 7. amide monomer NH R NH + H 2 acid Figure 6 Protection of polymerizable function (grey) in acryl monomer with amide functions. monomer content [%] NH NH amide monomer ester monomer time [days] Figure 7 Stability of an ester monomer versus an amide monomer in an acidic water/tert-butanol solvent solution while stored at 50 C. Scientific Compendium Xeno V 8

9 In addition to amide monomers, inverse functionalized monomers are used in Xeno V. These monomers are characterized by the attachment of the polymerizable methacrylate function to the acidic phosphoric acid ester function by a more hydrolysis-stable ether bond instead of an ester bond (Figure 8) a) ester functionalized phosphoric acid ester R P H H b) "inverse" functionalized phosphoric acid ester R' R P H H Figure 8 Ester functionalization (a) compared to inverse functionalization (b) Hydrolysis of such monomers does not lead to the separation of the polymerizable group from the acidic monomer (Figure 9). "inverse" functionalized phosphoric acid ester R' + R P H H H 2 acid H R P H H Figure 9 Acidic monomers maintain the polymerizable group (grey) over the shelf-life Summary of new chemistry The use of tert-butanol as part of the solvent, combined with acryl resins with amide functions, and inverse functionalization guarantees that polymerizable functions remain Scientific Compendium Xeno V 9

10 available to form a polymer network for the entire shelf-life even in a highly acidic aqueous one-component formulation. 2.2 Components and functions Besides their stability in an aqueous, acidic environment, each ingredient of Xeno V has to fulfil a specific function to guarantee the overall success of Xeno V. As crosslinkers, the bifunctional acryl resins with amide functions ensure the formation of a dense resin network upon light-curing. The inverse functionalized acidic monomer used in Xeno V comprises a phosphoric acid ester group (Figure 10). It has been demonstrated recently by µraman spectroscopy that such groups promote chemical interaction between the monomers and tooth substance (Latta, 2007a). R' R P H H Ca 2+ Ca 2+ Ca 2+ Figure 10 Possible interaction of phosphoric acid ester group with tooth substrate The second acidic monomer, the acryloylamino alkylsulfonic acid, was added to the formulation to increase the acidity of Xeno V and to ensure the formation of a well-defined etch pattern as described in the chapter Micro Morphology. Acrylic acid, although only a weak acid, plays an important role in the interaction of monomers. As a small polar, but also a polymerizable monomer, it promotes the penetration of the bigger crosslinker monomers into the tooth substrate. The use of a water/tert-butanol solvent solution provides the formulation with a well-balanced polarity. n one hand the polarity is high enough for the acidic monomers to be effective. n the other hand the polarity also allows less polar ingredients, like the initiators, to dissolve. In addition, the low volatility of the water/tert-butanol solvent solution makes it possible to use Xeno V from closed CliXdish for up to 30 min, making it more convenient in daily practice. Scientific Compendium Xeno V 10

11 3 In vitro Investigations Investigations under simulated conditions in vitro are necessary to verify the performance before new products can be evaluated in clinical studies. These investigations involve different aspects of variability including methods, operators, procedures and others, they can serve as a source of improvements in the application procedures so as to ensure reliable performance in everyday situations in the clinic. Investigations of bond strength, marginal quality, and micro morphology are described, below. 3.1 Adhesion ne of the most important features of Xeno V is that it can be stored at room temperature. But it was also very important to develop a product which can ensure balanced adhesion performance on both enamel and dentin Bond Strength to Dentin and Enamel Bond strength was tested at different sites by external experts and by DENTSPLY researchers under well established and standardized conditions Shear bond strength on enamel and dentin (Mark A. Latta, maha (NE), USA) ne experienced operator performed all samples for testing using a well described method (Barkmeier et al., 1999). Shear bond strength (SBS) was determined at a cross head speed of 5mm/min after 6000 thermo cycles (Figure 11), respectively. Scientific Compendium Xeno V 11

12 Shear Bond Strength [MPa] A a b Xeno V C a b ibond SE A b c B Ai a b AdheSE ne a Clearfil S3 c B B B B G Bond d ibond Gi A a b Clearfil SE Enamel Dentin ABC statistical grouping Figure 11 Shear bond strength after 6000 thermo cycles to dentin and enamel Xeno V showed high shear bond strength to both substrates dentin and enamel and was comparable to or better than Xeno III and other self-etching adhesive systems Shear bond strength after unintended pre-etching (DENTSPLY DeTrey, Konstanz, Germany) Xeno V is a self-etching adhesive. However, as for all other self-etching adhesives there is the limitation that bonding to unprepared enamel is not indicated. As the majority of practitioners prefer to use as few different adhesive products as possible, very often phosphoric etching gel is used in those indications to pre-etch unground enamel. When applying etch-gel to enamel margins (e.g. class IV cavities with extended bevelling) one may want to know whether unintended pre-etching of dentin together with the application of a self-etching adhesive leads to over etching of dentin and thus to decreased bond strength. Therefore, bond strength to dentin applying Xeno V in the intended self-etching mode was compared to situations in which unintended etching of dentin occurred. (Figure 12). In addition, either a QTH (Spectrum 800) or LED (SmartLite PS) curing light was used. Scientific Compendium Xeno V 12

13 Shear Bond Strength [MPa] Spectrum 800 SmartLite PS Figure 12 0 Self-Etch Etch&Rinse SBS on dentin after unintended pre-etching compared to self-etching mode Results support that Xeno V is compatible with halogen and LED curing lights and to unintentionally pre-etched dentin Micro Shear Fatigue Resistance (µsfr) to dentin (Marc Braem, Antwerp, Belgium) Achieving a long lasting bond between restoration and the tooth substance is the ultimate goal of adhesive dentistry. Besides chemical degradation, it might be expected that the adhesive degrades mechanically through fatigue. Therefore, a recently developed method (Braem, 2007) was used to investigate the fatigue behaviour of Xeno V and other adhesive systems. Tooth substance is placed and fixed in a brass mould (left picture of Figure 13). After the adhesive is applied and light cured, a Mylar strip with a hole 1 mm in diameter is centrically placed over this bonded surface (middle picture of Figure 13). Finally, another brass mould is fixed onto the first brass mould and composite is placed on top to bond through the 1 mm hole to the tooth surface (right picture of Figure 13). Figure 13 Specimen preparation (Braem, 2007) Scientific Compendium Xeno V 13

14 The assembled brass moulds are immediately placed into a test chamber under a constant temperature of 35 C where one brass mould is fixed and the other mould is loaded (Figure 14). Figure 14 Placement of the brass moulds in the fatigue machine. The lower part is fixed using compressed air (1). The piezo-electric force transducers (2) record the applied loads onto the upper part (Braem, 2007). Firstly, the quasi-static microshear strength is determined. The 50% value is then used as the starting level of the subsequent fatigue testing. Secondly, fatigue behaviour is tested in a staircase approach. The samples are loaded for up to 10,000 cycles to a specified limit with a frequency of 2 Hz. The load is increased by 8% of the initially determined microshear strength each time a specimen survives these 10,000 cycles, or decreased by 8% if the specimen fails prematurely. This staircase approach results in a set of data by which the mean fatigue resistance can be calculated. Scientific Compendium Xeno V 14

15 Figure 15 number of cycles sample µ-sfr Samples Exemplary data for number of cycles (bars) and respective load (dots) Applied stress [MPa] failed survived In Figure 15 exemplary data is used to illustrate the resulting set of data. The sample 001 was tested at a stress level of 20 MPa (right ordinate) and survived (green dot) 10,000 cylces (left ordinate). Therefore sample 002 was tested one step higher than sample 001 and survived as well. Sample 003 was stressed two steps higher compared to sample 001 but failed (red dot) after 500 cycles (bar). Sample 004 failed after 3700 cycles. Sample 005 was then tested at the same stress level as sample 001 and survived again. This method is followed until a sufficient amount of data for calculation of the mean Micro Shear Fatigue Resistance is available. Actual results are presented in Figure 16. µshear Fatigue Resistance [MPa] Xeno V Xeno III Clearfil SE ibond Gi 75% mean 25% Braem M (2006) Figure 16 Mean micro shear fatigue resistance to dentin and 25-75% quartiles Xeno V showed comparable or higher mean fatigue resistance compared to other selfetching adhesives. Distribution of data was significantly different for Xeno III compared to all other. Xeno V showed a comparable data distribution to the remaining adhesives tested with the 25% quartile being very close to the mean value. Scientific Compendium Xeno V 15

16 3.2 Marginal Integrity Bond strength is only the first step in evaluating the potential of a newly developed adhesive. To simulate the more complex configuration and stresses found in a restoration, marginal integrity was tested in different cavity classes using different methods in order to evaluate the quality of the margin before and after stress was applied Marginal Integrity of class V cavities Class V restorations allow easy access and simultaneous evaluation of marginal quality in enamel and dentin. To quantify the quality, either dye penetration or quantitative SEM analysis were applied Dye penetration and dentin permeability in class V (Juan Ignacio Rosales-Leal, Granada, Spain) After restoring U-shaped class V cavities with the materials displayed in Figure 18, teeth were thermo cycled between 5 and 55 C and immersed in a 0.5 % water solution of basic fuchsine for 24 hours, embedded in acrylic resin and cut into bucco-lingual slices. The in-vitro micro leakage of the occlusal and gingival cavity walls was evaluated using an optical microscope. The extent of the dye penetration along the restoration was ranked (Figure 17) between 0 (hermetic seal) and 3 (massive micro leakage). Additionally, it was documented whether, in the presence of dye along the cavo-restorative margin, any dye penetrated into dentin. 2 cclusal Wall = Enamel 3 0 Micro-Leakage Permeability 1 Gingival Wall = Dentine Microleakage grades 0: hermetic seal 1: mild 2: moderate 3: massive Dentin permeability 0: negative, dentin tubules sealed 1: positive, absence of dentin tubules sealing. Figure 17 Scoring of micro leakage in class V restorations The teeth were either stored for 24 hours in water, or thermo cycled (TC) 4000 times before being immersed in dye. Results are summarized for the enamel margin (Figure 18) and dentin margin (Figure 19). Scientific Compendium Xeno V 16

17 24 TC 24 TC 24 TC 24 TC 24 TC Percentage per grade [%] a ab a a a b a a a a Enamel 24 hours TC Xeno V Ceram X mono Xeno III Ceram X mono Adper Prompt Filtek Supreme ibond Gi Venus Clearfil SE Clearfil APX adhesive restorative Figure 18 Microleakage grades in enamel margins All restorative systems involved in the test showed mild penetration. There was no significant difference between Xeno V and Xeno III. 24 TC 24 TC 24 TC 24 TC 24 TC Percentage per grade [%] a a b cd d e ef f b d Dentin 24 hours TC Xeno V Ceram X mono Xeno III Ceram X mono Adper Prompt Filtek Supreme ibond Gi Venus Clearfil SE Clearfil APX adhesive restorative Rosales-Leal JI (2006) grades Figure 19 Microleakage grades in dentin margins In contrast to the results in enamel, micro leakage grades in dentin showed huge variation among the tested restorative systems. Xeno V in combination with Ceram X mono showed tighter margins in dentin compared to all other systems. Sealing the dentin is one of the main advantages of self-etching adhesives. In this in vitro testing dye did not penetrate into dentin tubules despite dye penetration between the cavity and the restoration for all systems except one (Figure 20). Scientific Compendium Xeno V 17

18 24 TC 24 TC 24 TC 24 TC 24 TC Percentage per grade [%] Dentin 24 hours TC Xeno V Ceram X mono Xeno III Ceram X mono Adper Prompt Filtek Supreme ibond Gi Venus Clearfil SE Clearfil APX adhesive restorative Figure 20 Dentin permeability under class V restorations In summary, Xeno V proved to be as good as well established systems with longer clinical history at restoring class V lesions in regard to micro leakage Marginal Quality of class V under SEM (Uwe Blunck, Berlin, Germany) Marginal quality of class V restorations using SEM was quantified in teeth after storage for 3 weeks in water and 2000 thermo cycles following a well established protocol (Blunck et al., 2007). Percentage of marginal line fulfilling the following criteria was determined (Figure 21): Margin not or hardly visible No or slight marginal irregularities 1 No gap restoration dentin enamel 100 µm restoration 100 µm Figure 21 Example of continuous margins using Xeno V / Ceram X mono 1 The term "marginal irregularities" means porosities, marginal restoration fracture, bulge in the restoration Scientific Compendium Xeno V 18

19 Data were analyzed regarding statistical significance comparing Xeno V to the other adhesives. To exclude any effect by the restorative material Ceram X mono was used for all groups. Results are presented for enamel margins (Figure 22) and dentin margins (Figure 23), respectively. perfect margins [%] p = p = p = p = before TC after TC 2000 outlier statistical differences Xeno V Xeno III Cf SE ibond Gi Prompt Blunck U (2006, 2007) Figure 22 Percentage of continuous margin in enamel 2 perfect margins [%] p < before TC after TC 2000 outlier statistical differences Xeno V Xeno III Cf SE ibond Gi Prompt Blunck U (2006, 2007) Figure 23 Percentage of continuous margin in dentin 2 The performance of Xeno V was comparable to Xeno III and Clearfil SE Marginal Integrity of class II cavities Marginal quality in class II restorations was investigated under two similar study designs. In both studies micro leakage was investigated. In one of the studies replicas were used to investigate marginal integrity as well. Class II studies are useful to create clinically relevant stress during restoration by applying a simplified incremental layer technique and using chewing simulator to challenge the adhesive system by forces from chewing and temperature changes. 2 Note: rdinate begins at 60%; * = outliers Scientific Compendium Xeno V 19

20 Dye penetration in class II (Jürgen Manhart, Munich, Germany) There are numerous protocols as to how and where to place increments and light source in the restoration of class II cavities. As most practitioners tend to use simplified techniques, such a layering concept was applied for this investigation (Figure 24). Box in enamel Box in dentine cclusal part Manhart J (1999) Figure 24 Layering concept for class II cavities and directions of light source After restoration, the teeth were stressed in a chewing simulator by 2000 thermo cycles between 5 and 55 C, and 50,000 chewing cycles using an artificial antagonist loaded with 50N (Manhart et al., 1999). Dye penetration was evaluated separately for enamel margins in the approximal box limited to enamel (Figure 25) and dentin margins in the deeper approximal box (Figure 26). dye penetration score [%] a b a a b b b Microleakage scores for class II restorations limited within enamel Enamel Dentin 0 Xeno V Ceram X mono Xeno III Ceram X mono Clearfil SE Clearfil APX ibond Gi Venus Adper Prompt Filtek Supr. XT adhesive restorative Manhart J (2006) Figure 25 Microleakage scores in enamel margins of class II restorations. Scientific Compendium Xeno V 20

21 dye penetration score [%] a a a b b b c c Microleakage scores for class II restorations limited within dentin Dentin 0 Xeno V Ceram X mono Xeno III Ceram X mono Clearfil SE Clearfil APX ibond Gi Venus Adper Prompt Filtek Supr. XT adhesive restorative Manhart J (2006) Figure 26 Microleakage scores in dentin margins of class II restorations. In enamel restorations of Xeno V and Ceram X mono performed as good as all other restorative systems. In dentin Xeno V showed comparable leakage to all other systems except Clearfil SE / Clearfil APX which performed better Dye penetration and marginal integrity in class II (Roland Frankenberger, Erlangen, Germany) This investigation of marginal quality, following an almost identical protocol (Figure 27), combined SEM evaluation via replica with slicing and determination of dye penetration. Materials & Method - n = 8 mod (box in Dentin or enamel) Storage & Stressing - 24 hours at 37 C TC 5-55 C for 30 seconds - 100,000 cycles with 50 N Evaluation - dye penetration (32 slices) - SEM Frankenberger R (2007) Figure 27 Parameters for class II testing in chewing simulator. Scientific Compendium Xeno V 21

22 percenatage perfect margins [%] Xeno V Ceram X mono Xeno III Ceram X mono Enamel Before TML Dentin After TML Before TML After TML Frankenberger R (2007) Figure 28 Percentage of perfect margins before and after thermo mechanical loading (TML) Xeno V performed similar to Xeno III when determining the percentage of perfect margins either in enamel or in dentin and before or after thermo mechanical loading. After slicing the restorations for which marginal integrity data is shown in Figure 28 microleakage scores by means of dye penetration was determined as shown for enamel in Figure 29 and for dentin in Figure 30. dye penetration score [%] a b Microleakage scores for class II restorations limited within enamel Dentin 0 Xeno V Ceram X mono Xeno III Ceram X mono Enamel Frankenberger R (2007) Figure 29 Microleakage scores in enamel margins of class II. In enamel margins Xeno V performed better compared to Xeno III. Scientific Compendium Xeno V 22

23 dye penetration score [%] a a Microleakage scores for class II restorations limited within dentin Dentin 0 Xeno V Ceram X mono Xeno III Ceram X mono Figure 30 Microleakage scores in dentin margins of class II. In dentin margins both systems performed on the same level. In summary this investigation supports the hypothesis that Xeno V is at least comparable to Xeno III as regards performance. 3.3 Micro Morphology Investigations of micro morphology help to visualize the effects adhesives have on the respective substrate FESEM investigation of etching pattern in enamel and hybrid layer in dentin (Jorge Perdigão, Minneapolis (MN), USA) Enamel specimens were roughened with a course diamond bur and after application of Xeno V were immersed in acetone for 24 h in a rotator to dissolve the resin. The application of Xeno V resulted in very good intraprismatic penetration into enamel, however its interprismatic penetration was shallow, which is characteristic of self-etch adhesives. (Figure 31) Scientific Compendium Xeno V 23

24 Perdigão J (2006) Figure 31 SEM of enamel treated with Xeno V The investigator compared these findings to previous results from other self-etching adhesives and stipulated that Xeno V resulted in more defined enamel etching pattern than self-etch adhesives with ph 1.8. The interaction of Xeno V with dentin and the resulting hybridisation is described as follows: hybrid layer thickness 0.2 μm to 0.5 μm adhesive layer thickness 3.4 μm to 4.8 μm resin tags were observed 120 μm below the interface no debonding was observed the hybrid layer showed the typical reticular aspect In summary the micro morphology data show the well defined interaction of Xeno V with both substrates enamel and dentin. It complements the favourable performance found in other kind of investigations. Scientific Compendium Xeno V 24

25 4 Clinical Investigations Despite the significance of the above in-vitro investigations, conducted both internally and externally, clinical investigations are the only method of providing absolute certainty concerning the efficacy of new restorative technologies. Therefore three clinical investigations on Xeno V have recently been initiated in different cavity classes. Some brief information is provided below on the design and status of these studies. 4.1 Clinical Class V Studies at the Medical University of Berlin and Bologna University Due to their non-retentive nature and their special stress pattern, the follow up of Class V restorations is most helpful in revealing potential weaknesses of adhesives. Therefore data on clinical success of Class V s is essential. Dr. Uwe Blunck from the Medical University of Berlin, Germany, and Professor Giovanni Dondi dall rologio from Bologna University, Italy, are running two randomized longitudinal clinical investigations on restoration of caries free cervical lesions. At each site, 40 Xeno V plus 40 controls (40 Xeno III or 40 Clearfil SE restorations, respectively) have been placed in 40 patients. Ceram X duo, DENTSPLY, is used as restorative material. The restoration margins are primarily in dentin. Both studies are identical in design in order to enable pooling of the results for Xeno V. RYGE criteria are applied. perator calibration was conducted at both sites prior to commencement of trials. The investigations were designed according to the revised guidelines of the American Dental Association (ADA, 2001a) for dentin and enamel adhesive materials; details are provided in Table 4. Scientific Compendium Xeno V 25

26 Number of patients per site Number of restorations per site Test adhesive Control materials Restorative Method of evaluation Recall periods Blinding 40 to be included, each receiving one test and one control restoration 40 test and 40 control restorations Xeno V Xeno III (Berlin) and Clearfil SE (Bologna) Ceram X duo Clinical examination (RYGE criteria) Baseline, 3, 6, 18 and 48 months Patient and operator blinding Table 4 Design details on Class V investigations at Berlin and Bologna University The results recorded over the 18-month period from Bologna University are available and are provided in Table 5 and Table 6. Criteria Xeno V / Ceram X [n] Clearfil SE / Ceram X [n] alpha bravo charl. delta alpha bravo charl. delta Retention n/a 0 n/a n/a 0 n/a Marginal discolouration n/a n/a Marginal integrity Secondary caries n/a n/a n/a n/a Restoration contour n/a n/a Table 5 18 month results in Class V, Bologna University (Dondi dall'rologio, 2008) Post-op. sensitivities total no yes mean SD total no yes mean SD n/a n/a n/a n/a Table 6 Post-operative sensitivities at 18 months, University of Bologna. Mean value and standard deviation. 1 = lowest sensitivity. 10 = highest sensitivity. (Dondi dall'rologio, 2008) 18 patients and 36 teeth were sensitive to stimuli (score 2 or 3 in a category of 0 to 4) before treatment and rated score 0 (no sensitivity) at baseline control. This was evaluated between 3 and 7 days after placement. After 18 months, the success rates achieved at Bologna University amounted to 100% for Xeno V and 100% for Clearfil SE. No adverse events occurred. The results recorded over the 18-month period from The Medical University Berlin (Charité) are available as well and displayed below in Table 7 and Table 8. Scientific Compendium Xeno V 26

27 Criteria Xeno V / Ceram X duo [n] Xeno III / Ceram X duo [n] alpha bravo charl. delta alpha bravo charl. delta Retention n/a 2 n/a n/a 6 n/a Marginal discolouration n/a n/a Marginal integrity Secondary caries n/a n/a n/a n/a Restoration contour n/a n/a Table 7 18 month results in Class V, University of Berlin (Blunck, 2008) Post-op. sensitivities total no yes mean SD total no yes mean SD n/a n/a n/a n/a Table 8 Post-operative sensitivities at 18 months, University of Berlin. Mean value and standard deviation. 1 = lowest sensitivity. 10 = highest sensitivity. (Blunck, 2008) The overall success rate amounts to 92.3% for Xeno V and 78.1% for Xeno III. No adverse events or other clinical problems occurred. Principal Clinical Investigator Uwe Blunck concluded that the use of Xeno V was both safe and efficient. 4.2 Clinical Class II Study at Freiburg University The clinical behaviour of Xeno V in Class II cavities is of particular interest because it is one of the major indications of modern adhesive materials. Accordingly, a randomized controlled longitudinal Class II investigation is underway at the University of Freiburg, Germany, under the auspices of Professor Elmar Hellwig. 40 Xeno V restorations plus an according number of control restorations (Syntac Classic) have been placed in 40 patients. Ceram X mono, DENTSPLY, is used as restorative material. RYGE criteria are applied. The investigation was designed according to the revised guidelines of the American Dental Association (ADA, 2001b) for posterior restorations, details are provided in Table 9. Scientific Compendium Xeno V 27

28 Number of patients Number of restorations Test adhesive Control adhesive Restorative Method of evaluation Recall periods Blinding 40 to be included, each receiving one test and one control restoration 40 test and 40 control restorations Xeno V Syntac Classic Ceram X mono Clinical examination (RYGE criteria) Baseline, 3, 6 and 18 months Patient and operator blinding Table 9 Design details on Class II investigation at Freiburg University The 6 months results on 32 patients have been received from the University of Freiburg and are displayed below (Table 10 and Table 11). Criteria of evaluated restorations Xeno V / Ceram X mono [n] Syntac Classic / Ceram X mono [n] total alpha bravo charl. delta total alpha bravo charl. delta Retention n/a 0 n/a n/a 1 n/a Marginal discolouration n/a n/a Marginal integrity Secondary caries n/a n/a n/a n/a Prox. contact/ cont. (d) n/a n/a Prox. contact/ cont. (m) n/a n/a Vitality test Fracture Table 10 6 months results in Class II, University of Freiburg (Hellwig, 2008) Post-op. sensitivities total no yes mean SD total no yes mean SD spontaneous n/a n/a n/a n/a triggered by chewing n/a n/a n/a n/a triggered by other noxa n/a n/a ( ) n/a n/a Table 11 Post-operative sensitivities at 6 months, University of Freiburg. Mean value and standard deviation. 1 = lowest sensitivity. 10 = highest sensitivity. (Hellwig, 2008) Scientific Compendium Xeno V 28

29 Principal Clinical Investigator Elmar Hellwig concludes that presently no clinically relevant differences between the two experimental groups neither in occurrence nor in the severity of post-operative sensitivity can be stated. 4.3 Conclusion from the results of the clinical studies The success rate of Xeno V in class V amounts to 98,7% after 6 months. In class II, the observed results indicate no clinical difference between the used adhesive systems. Adverse events were not observed in any study. Scientific Compendium Xeno V 29

30 5 Directions for Use The up-to-date directions for use can be found in all European official languages on the Internet at Scientific Compendium Xeno V 30

31 6 References ADA (2001a). American Dental Association Council on Scientific Affairs: Guidelines for Acceptance of Enamel and Dentin Adhesive Materials. American Dental Association, Chicago, May ADA (2001b). American Dental Association Council on Scientific Affairs: Resin Based Composites for Posterior Restorations. American Dental Association, Chicago, May Barkmeier WW, Hamesfahr PD, Latta MA (1999). Bond Strength of Composite to Enamel and Dentin Using Prime and Bond 2.1. perative Dentistry 24:1, Blunck U, Zaslansky P (2007). Effectiveness of All-in-one Adhesive Systems Tested by Thermocycling Following Short and Long-term Water Storage. J Adhes Dent 2007; 9: Blunck U (2006). Final Report Data on file. Blunck U (2007). Final Report Data on file. Blunck U (2008). 18-month report Data on file. Braem M (2006). Final Report Data on file. Braem M (2007). Microshear Fatigue Testing of Tooth/AdhesiveInterfaces. J Adhes Dent 2007; 9: Dondi dall'rologio G (2008). 18-month report Data on file. Frankenberger R (2007). Final Report Data on file. Hellwig E (2008). 6-month report Data on file. Krämer N, Frankenberger R (2007). Compomers in restorative therapy of children: a literature review. Int J Paed Dent 17:2-9. Latta MA (2007a). Shear Bond Strength and Physicochemical Interactions of XP BND. J Adhes Dent 2007; 9: Latta MA (2008). Bond Strength of Composite to Dentin and Enamel Using Self-Etching Adhesive Systems. General Dentistry. Accepted for publication. Manhart J, Hollwich B, Mehl A, Kunzelmann K-H, Hickel R (1999). Randqualität von rmocer- und Kompositfüllungen in Klasse-II-Kavitäten nach künstlicher Alterung. Dtsch Zahnärztl Z; 54:89-95 Manhart J (2006). Final Report Data on file. Perdigão J (2006). Final Report Data on file. Rosales-Leal JI (2006). Final Report Data on file. Scientific Compendium Xeno V 31

32 7 Glossar and Abreviations FESEM LED µsfl QTH SBS SEM TC TML Field Emission Scanning Electron Microscopy Light Emitting Diode Micro Shear Fatigue Limit Quartz Tungsten Halogen Shear Bond Strength Scanning Electron Microscope Thermo Cycles Thermo Mechanical Loading Scientific Compendium Xeno V 32

33 8 List of Figures Figure 1 Addition of solvent molecules (i.e. ethanol) to polymerizable groups (grey) results in loss of the polymerizable function (open circle) (X = for ester; X = NH for amide)...4 Figure 2 Separation of polymerizable groups (grey) by hydrolysis...4 Figure 3 Chemical structure of alcohols...7 Figure 4 Addition to polymerizable groups does not occur with tert-butanol (X = for ester; X = NH for amide)...7 Figure 5 General chemical structures of the key monomers used in Xeno V....8 Figure 6 Protection of polymerizable function (grey) in acryl monomer with amide Figure 7 functions....8 Stability of an ester monomer versus an amide monomer in an acidic water/tertbutanol solvent solution while stored at 50 C....8 Figure 8 Ester functionalization (a) compared to inverse functionalization (b)...9 Figure 9 Acidic monomers maintain the polymerizable group (grey) over the shelf-life...9 Figure 10 Possible interaction of phosphoric acid ester group with tooth substrate...10 Figure 11 Shear bond strength after 6000 thermo cycles to dentin and enamel...12 Figure 12 SBS on dentin after unintended pre-etching compared to self-etching mode...13 Figure 13 Specimen preparation (Braem, 2007)...13 Figure 14 Placement of the brass moulds in the fatigue machine. The lower part is fixed using compressed air (1). The piezo-electric force transducers (2) record the applied loads onto the upper part (Braem, 2007) Figure 15 Exemplary data for number of cycles (bars) and respective load (dots)...15 Figure 16 Mean micro shear fatigue resistance to dentin and 25-75% quartiles...15 Figure 17 Scoring of micro leakage in class V restorations...16 Figure 18 Microleakage grades in enamel margins...17 Figure 19 Microleakage grades in dentin margins...17 Figure 20 Dentin permeability under class V restorations...18 Figure 21 Example of continuous margins using Xeno V / Ceram X mono...18 Figure 22 Percentage of continuous margin in enamel...19 Figure 23 Percentage of continuous margin in dentin Figure 24 Layering concept for class II cavities and directions of light source...20 Figure 25 Microleakage scores in enamel margins of class II restorations Figure 26 Microleakage scores in dentin margins of class II restorations Figure 27 Parameters for class II testing in chewing simulator Figure 28 Percentage of perfect margins before and after thermo mechanical loading (TML)...22 Figure 29 Microleakage scores in enamel margins of class II Figure 30 Microleakage scores in dentin margins of class II Figure 31 SEM of enamel treated with Xeno V...24 Scientific Compendium Xeno V 33

34 9 List of Tables Table 1 Storage conditions of two-component self-etching adhesives...5 Table 2 Storage conditions for one-component self-etching adhesives according to the respective manufacturer instructions...5 Table 3 Components of Xeno V and their function...6 Table 4 Design details on Class V investigations at Berlin and Bologna University...26 Table 5 18 month results in Class V, Bologna University (Dondi dall'rologio, 2008)...26 Table 6 Post-operative sensitivities at 18 months, University of Bologna. Mean value and standard deviation. 1 = lowest sensitivity. 10 = highest sensitivity. (Dondi dall'rologio, 2008)...26 Table 7 18 month results in Class V, University of Berlin (Blunck, 2008)...27 Table 8 Post-operative sensitivities at 18 months, University of Berlin. Mean value and standard deviation. 1 = lowest sensitivity. 10 = highest sensitivity. (Blunck, 2008)...27 Table 9 Design details on Class II investigation at Freiburg University...28 Table 10 6 months results in Class II, University of Freiburg (Hellwig, 2008)...28 Table 11 Post-operative sensitivities at 6 months, University of Freiburg. Mean value and standard deviation. 1 = lowest sensitivity. 10 = highest sensitivity. (Hellwig, 2008)...28 Scientific Compendium Xeno V 34

35 The following materials are not trademarks of DENTSPLY International but of the respective manufacturer. Abreviation AdheSE ne Adper Prompt CfSE Cf APX Clearfil S3 FSupXT G Bond ibond Gi ibond SE B Ai Z250 Brand (Manufacturer) AdheSE ne (Ivoclar Vivadent) Adper Prompt L-Pop (3M Espe) Clearfil SE Bond (Kuraray) Clearfil APX (Kuraray) Clearfil S 3 Bond (Kuraray) Filtek Supreme XT (3M Espe) G Bond (GC) ibond Gluma inside (Heraeus Kulzer) ibond Self Etch (Heraeus Kulzer) ptibond All in ne (Kerr) Filtek Z250 (3M Espe) Scientific Compendium Xeno V 35