Diana Wolff - Academia.edu (original) (raw)

Papers by Diana Wolff

Research paper thumbnail of CLSM-study on penetration of adhesives into fiber-reinforced-composites

Objectives: The aim of the study was to compare the penetration of an adhesive into fiber-reinfor... more Objectives: The aim of the study was to compare the penetration of an adhesive into fiber-reinforced-composites (FRC) with either interpenetrating-polymer-network (IPN) or cross-linked-polymer (CLP) matrix. Methods: 5 materials were tested including one IPN-FRC (everStick-C&B, StickTech) and four CLP-FRCs (GrandTec,VOCO; Dentapreg, ADM; TenderFiber, Micerium; Splint-It, Pentron). FRC strands were light polymerized, oxygen-inhibition-layer was removed, adhesive (Optibond-FL, Kerr) was labelled with fluorescent dye (rhodamine-B), applied on FRCs (5 min) and light polymerized (40 sec). Specimens were prepared for confocal laser scanning microscopy. 15 FRC strands (3 per group) were sectioned into 3 specimens each and depth of adhesive penetration was measured at 4 sites (n=36 per group). Depth of penetration could be clearly detected since monomers of the adhesive material were able to penetrate into FRC strands whereas filler particles of adhesive material were not. Width of fluoresce...

Research paper thumbnail of Quantitative real-time PCR for detecting oral bacteria

Objective: The aim of the study was to establish and validate a quantitative real-time PCR assay ... more Objective: The aim of the study was to establish and validate a quantitative real-time PCR assay (RQ-PCR) for typing a broad spectrum of caries and health associated oral bacteria. Methods: 140 PCR primers for relevant caries and health associated species were designed by aligning primer sequences against data from the Ribosomal Database Project and against human genome sequence. Samples of plaque (n=5 patients without caries) and carious dentin (n=5 patients with caries) were collected and bacterial DNA was isolated using QIAamp DNA Mini Kit (Qiagen). RQ-PCR was performed in duplicates (reaction volume 12 l - 1x SYBR Green PCR Master Mix, 0.33 M specific primer, 3 ng extracted template DNA) on an ABI PRISM 7900 Sequence Detection System in 384-well PCR plates (95C for 15 min, 40 cycles of 95C for 15 s, 60C for 1 min). Data analysis was conducted with Sequence Detection Software version 2.1. Specificity of PCR products was tested by melting-curve analysis with Sequence Detection Sof...

Research paper thumbnail of A 6.5-year clinical follow-up of direct resin composite buildups in the posterior dentition: Introduction of a new minimally invasive restorative method

Journal of dentistry, Jan 9, 2015

Restorative rehabilitation of missing single teeth in the posterior dentition is achieved primari... more Restorative rehabilitation of missing single teeth in the posterior dentition is achieved primarily by dental implants or fixed dental prostheses. Here we introduce an uncommon, minimally invasive treatment option in order to close single tooth gaps. The purpose of this study was to evaluate the clinical quality and survival of 45 direct composite buildups in the posterior dentition. A detailed clinical examination was performed, and restorations were rated qualitatively using the modified USPHS/FDI criteria. The mean extension of the direct composite buildups was 2.96 (1.12)mm per tooth. Interdental closures from both adjacent teeth had a significantly higher extension of the direct composite buildups than one-sided interdental closures (p=0.03). Patients with a history of prior tooth loss showed a significantly greater extension of direct composite buildups than patients without prior tooth loss (p=0.006). During the follow-up period, no restoration showed unfavorable events. The ...

Research paper thumbnail of Faserverstärkte Kompositbrücken

Zahnmedizin up2date, 2009

Research paper thumbnail of More conservative dentistry: Clinical long-term results of direct composite resin restorations

Quintessence international (Berlin, Germany : 1985), 2015

Current treatment protocols and recent developments in composite resin technology allow for exten... more Current treatment protocols and recent developments in composite resin technology allow for extended indication of direct composite resin restorations. This article presents clinical longterm observations of direct composite resin restorations indicated for primary and replacement therapy, repair restorations, direct crowns, and composite buildups for the correction of tooth form.

Research paper thumbnail of Mineral trioxide aggregate or calcium hydroxide direct pulp capping: an analysis of the clinical treatment outcome

Journal of endodontics, 2010

The use of mineral trioxide aggregate (MTA) might improve the prognosis of teeth after pulp expos... more The use of mineral trioxide aggregate (MTA) might improve the prognosis of teeth after pulp exposure. The treatment outcome of teeth after direct pulp capping, either with mineral trioxide aggregate (MTA) or calcium hydroxide (controls), was investigated, taking into account possible confounding factors. One hundred forty-nine patients treated between 2001 and 2006 who received direct pulp capping treatment in 167 teeth met the inclusion criteria. Treatment was performed by supervised undergraduate students (72%) and dentists (28%). Assessment of clinical and radiographic outcomes was performed by calibrated examiners 12-80 months after treatment (median, 27 months). One hundred eight patients (122 treated teeth) were available for follow-up (72.5% recall rate). A successful outcome was recorded for 78% of teeth (54 of 69) in the MTA group and for 60% of teeth (32 of 53) in the the calcium hydroxide group. The univariate analysis (generalized estimation equations model [GEE model] s...

Research paper thumbnail of Assessment of the reliability and validity of panoramic imaging for assessment of mandibular condyle morphology using both MRI and clinical examination as the gold standard

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2006

Research paper thumbnail of Proximal Contact Tightness Between Direct-composite Additions in the Posterior Dentition: An In Vitro Investigation

Operative Dentistry, 2012

Research paper thumbnail of The assessment of dentofacial esthetics in restorative dentistry: A review of the literature

Journal of the American Dental Association, 2012

The authors conducted a literature review to determine how dentofacial esthetics can be evaluated... more The authors conducted a literature review to determine how dentofacial esthetics can be evaluated in restorative dentistry and which quantifiable clinical parameters can be used for this assessment of dentofacial esthetics. The authors selected 35 studies that focused on assessment strategies for dental professionals. The primary inclusion criteria were intraoral and extraoral esthetic assessment methods and indexes or rating scales evaluating esthetics in restorative dentistry. The studies' protocols and assessment methods were heterogeneous. The authors grouped the studies into six categories according to topic: golden proportion, soft-tissue measurement, smile and smile line assessment, orofacial indexes and scales, incisor proportion and angulation, and facial esthetics. These categories included various esthetic parameters, including the smile line, lip line, incisal offset, location of dental and facial midline, incisor angulations and width to height ratios of the maxillary anterior teeth, gingival contour, and root coverage and papilla height. These parameters should be considered when providing dental treatment in the anterior area, as they allow for quantification and objective judgment. The findings of this review might increase interest in a comprehensive dental esthetic index that allows for objective quantification and intrastudy and interstudy comparison of dental treatment outcomes.

Research paper thumbnail of Fiber-reinforced composite fixed dental prostheses in the anterior area: A 4.5-year follow-up

The Journal of Prosthetic Dentistry, 2014

To obtain survival data on 32 fiber-reinforced fixed dental prostheses which were inserted in our... more To obtain survival data on 32 fiber-reinforced fixed dental prostheses which were inserted in our department and to rate the quality of these restorations on the basis of esthetic, biological, and functional parameters. Thirty-two patients with fiber-reinforced fixed dental prostheses were included in the study. The fiber frameworks were made of a polymer-monomer-preimpregnated continuous unidirectional glass fiber material. The survival times, failure events, and clinical parameters were recorded. Restorations in function without previous failure were classified as "Overall Survival". The classification "Functional Survival" was assigned in the event of minor failure and subsequent repair. Loss of the restoration was regarded as "Failure". The quality rating was performed using modified USHPS/Ryge criteria. The follow-up interval ranged from 2 to 64 months with a median follow-up time of 18.2 months. Twenty-four restorations were classified as "Overall Survival", seven were classified as "Functional Survival", and one was classified as "Failure". The overall survival at the median follow-up time was 74.4%. For the majority, the quality rating (USHPS/Ryge criteria) yielded clinically excellent results in all categories. No restoration was rated as insufficient or poor. Fiber-reinforced composite fixed dental prostheses provide sufficient stability and very good esthetic, biological, and functional performance in the case of specific clinical indications.

Research paper thumbnail of Influence of marginal and segmental mandibular resection on the survival rate in patients with squamous cell carcinoma of the inferior parts of the oral cavity

Journal of Cranio-Maxillofacial Surgery, 2004

Research paper thumbnail of Original and repair bond strength of fiber-reinforced composites in vitro

Dental Materials, 2014

A great benefit of FRC technology is that, in case of minor failure events, restorations can be r... more A great benefit of FRC technology is that, in case of minor failure events, restorations can be repaired or reinserted. However, various FRC materials are available, that differ in matrix composition and fiber pre-treatment. The aim of this investigation was, therefore, to evaluate original and repair bond strength of FRC materials. Five fully pre-impregnated, unidirectional FRCs were selected, one semi-interpenetrating polymer network FRC and four cross-linked-polymer FRCs. The primary endpoint was the evaluation of shear bond strength (SBS) between FRC and composite resin, which was performed by a universal testing machine. For each FRC specimens were divided into control (original SBS, resin to fresh FRC with oxygen inhibition layer (OIL), n=30) and test groups (repair SBS, resin to FRC after removal of OIL and adhesive infiltration, n=30). The cross-linked-polymer FRC GrandTec(®) (12.4±5.4 MPa) yielded the highest control SBS, followed by the semi-interpenetrating polymer network FRC (everStick(®), 9.2±3.5 MPa). With everStick(®), repair led to a significant increase in the test SBS (14.6±5.8 MPa, p=0.01). Control SBS was best with GrandTec(®) indicating that the material is superior in direct clinical application. Test SBS was significantly increased with everStick(®) which points at potential reparability and advantages in semi-direct or indirect fabrication of fiber-reinforced fixed partial dentures.

Research paper thumbnail of Relationship between microtensile bond strength and submicron hiatus at the composite–dentin interface using CLSM visualization technique

Research paper thumbnail of Analysis of the interdiffusion of resin monomers into pre-polymerized fiber-reinforced composites

Dental Materials, 2012

The aim of the study was to analyze the dissolving depth of adhesive resin monomers into pre-poly... more The aim of the study was to analyze the dissolving depth of adhesive resin monomers into pre-polymerized fiber-reinforced composites (FRC) with either a semi-interpenetrating polymer network (semi-IPN) or a cross-linked polymer (CLP) matrix. Five unidirectional FRCs were tested, including one semi-IPN FRC (everStick(®) C&B, StickTech, (ES)) and four CLP-FRCs (GrandTec(®), VOCO, (GT); Dentapreg(®), ADM, (DP); TenderFiber(®), Micerium, (TF); Splint-It(®), Pentron Clinical Technologies, (SI)). The FRCs were light-polymerized following manufacturers' instructions: the oxygen inhibition layers were removed and the adhesive resin (Optibond-FL(®), KerrHawe) was labeled with a fluorescent dye (Rhodamine-B-isothiocyanate), which was then applied to the FRCs (5 min) and light-polymerized (40s). Specimens were then prepared for confocal laser scanning microscopy. Three FRC strands per group were sectioned orthogonally to the direction of fibers, thus forming nine slices in each group. Four images were taken from each slice and the depths of adhesive penetration were measured in four sites per image (n=144 measurements per group). Dissolving depths were 17.28 (3.04) μm (ES), 12.58 (2.94) μm (SI), 7.57 (1.91) μm (TF), 3.27 (0.73) μm (DP) and 2.55 (0.63) μm (GT). Samples were normally distributed. Differences between groups were analyzed by ANOVA (PostHoc Scheffé) showing four subgroups (p=0.05). The infiltration layers detected were either continuous/homogenous (ES, TF, DP GT) or discontinuous/insular (SI). The adhesive resin monomers were able to diffuse significantly deeper into pre-polymerized semi-IPN specimens than into CLP materials. Semi-IPN specimens showed a homogenous and comparatively deeper layer of infiltration. The diffusion capabilities of secondary-IPN formation might increase the opportunity to establish a good bond between pre-polymerized FRC and new resin.

Research paper thumbnail of Bacterial Biofilm Composition in Caries and Caries-Free Subjects

Caries Research, 2013

Certain major pathogens such as Streptococcus mutans, Lactobacillus spp. and others have been rep... more Certain major pathogens such as Streptococcus mutans, Lactobacillus spp. and others have been reported to be involved in caries initiation and progression. Yet, in addition to those leading pathogens, microbial communities seem to be much more diverse and individually differing. The aim of this study, therefore, was to analyze the bacterial composition of carious dentin and the plaque of caries-free patients by using a custom-made, real-time quantitative polymerase chain reaction assay (RQ-PCR). The study included 26 patients with caries and 28 caries-free controls. Decayed tooth substance and plaque samples were harvested. Bacterial DNA was extracted and tested for the presence of 43 bacterial species or species groups using RQ-PCR. Relative quantification revealed that Propionibacterium acidifaciens was significantly more abundant in caries samples than were other microorganisms (fold change 169.12, p = 0.023). In the caries-free samples, typical health-associated species were significantly more prevalent. Unsupervised hierarchical cluster analysis showed a high abundance of P. acidifaciens in caries subjects and distinct but individually differing bacterial clusters in the caries-free subjects. The distribution of 11 bacteria allowed full discrimination between caries and caries-free subjects. Within the investigated cohort, P. acidifaciens was the only pathogen significantly more abundant in caries subjects. Cluster analysis yielded a diverse flora in caries-free subjects, whereas it was narrowed down to a small range of a few outcompeting members in caries subjects.

Research paper thumbnail of Cytotoxicity of coated and uncoated fibre-reinforced composites

Acta Odontologica Scandinavica, 2014

Currently, there are many fibre-reinforced composites (FRCs) available which differ in the type a... more Currently, there are many fibre-reinforced composites (FRCs) available which differ in the type and volume fraction of fibres, pre-treatment of fibres and matrix composition. The aims of this in vitro investigation were to determine whether there is a difference in biocompatibility of FRCs and if coating FRCs with resin composites influences their cytotoxic potential. Five different FRC materials were tested which were either uncoated or coated with flowable or viscous resin composite. Artificial saliva extracts were prepared according to USP-XXIII and ISO-10993 to determine cytotoxicity by testing cell viability and growth of primary human gingival fibroblasts (HGF) using MTT assay, LIVE/DEAD(®) assay and cell proliferation assay. The influence of eluates on fibres of the cytoskeleton was investigated by vimentin, tubulin and actinin immunostainings. A two-way ANOVA followed by Scheffe's post-hoc test, which included the factors FRC material and coating procedure, was performed to assess cytotoxicity. All extracts of FRC materials displayed minor cytotoxic potential on HGF cell viability, cell proliferation and integrity of the cytoskeleton. The type of FRC material significantly influenced cell viability (MTT assay) (p < 0.0001), whereas neither the presence of a coating nor the type of coating material resulted in altered cell viability. Distribution and organization of cytosolic fibres was not affected after HGF exposure to eluates. There is a lack of knowledge about the leaching behaviour of commonly available fully pre-impregnated FRCs and their interactions with coating materials. The coating of FRCs with resin composite materials did not impact biocompatibility.

Research paper thumbnail of Recontouring teeth and closing diastemas with direct composite buildups: A clinical evaluation of survival and quality parameters

Research paper thumbnail of The outcome of various cements in combination with titanium reconstruction plates after segmental resection of the mandible

British Journal of Oral and Maxillofacial Surgery, 2005

Research paper thumbnail of CLSM-study on penetration of adhesives into fiber-reinforced-composites

Objectives: The aim of the study was to compare the penetration of an adhesive into fiber-reinfor... more Objectives: The aim of the study was to compare the penetration of an adhesive into fiber-reinforced-composites (FRC) with either interpenetrating-polymer-network (IPN) or cross-linked-polymer (CLP) matrix. Methods: 5 materials were tested including one IPN-FRC (everStick-C&B, StickTech) and four CLP-FRCs (GrandTec,VOCO; Dentapreg, ADM; TenderFiber, Micerium; Splint-It, Pentron). FRC strands were light polymerized, oxygen-inhibition-layer was removed, adhesive (Optibond-FL, Kerr) was labelled with fluorescent dye (rhodamine-B), applied on FRCs (5 min) and light polymerized (40 sec). Specimens were prepared for confocal laser scanning microscopy. 15 FRC strands (3 per group) were sectioned into 3 specimens each and depth of adhesive penetration was measured at 4 sites (n=36 per group). Depth of penetration could be clearly detected since monomers of the adhesive material were able to penetrate into FRC strands whereas filler particles of adhesive material were not. Width of fluoresce...

Research paper thumbnail of Quantitative real-time PCR for detecting oral bacteria

Objective: The aim of the study was to establish and validate a quantitative real-time PCR assay ... more Objective: The aim of the study was to establish and validate a quantitative real-time PCR assay (RQ-PCR) for typing a broad spectrum of caries and health associated oral bacteria. Methods: 140 PCR primers for relevant caries and health associated species were designed by aligning primer sequences against data from the Ribosomal Database Project and against human genome sequence. Samples of plaque (n=5 patients without caries) and carious dentin (n=5 patients with caries) were collected and bacterial DNA was isolated using QIAamp DNA Mini Kit (Qiagen). RQ-PCR was performed in duplicates (reaction volume 12 l - 1x SYBR Green PCR Master Mix, 0.33 M specific primer, 3 ng extracted template DNA) on an ABI PRISM 7900 Sequence Detection System in 384-well PCR plates (95C for 15 min, 40 cycles of 95C for 15 s, 60C for 1 min). Data analysis was conducted with Sequence Detection Software version 2.1. Specificity of PCR products was tested by melting-curve analysis with Sequence Detection Sof...

Research paper thumbnail of A 6.5-year clinical follow-up of direct resin composite buildups in the posterior dentition: Introduction of a new minimally invasive restorative method

Journal of dentistry, Jan 9, 2015

Restorative rehabilitation of missing single teeth in the posterior dentition is achieved primari... more Restorative rehabilitation of missing single teeth in the posterior dentition is achieved primarily by dental implants or fixed dental prostheses. Here we introduce an uncommon, minimally invasive treatment option in order to close single tooth gaps. The purpose of this study was to evaluate the clinical quality and survival of 45 direct composite buildups in the posterior dentition. A detailed clinical examination was performed, and restorations were rated qualitatively using the modified USPHS/FDI criteria. The mean extension of the direct composite buildups was 2.96 (1.12)mm per tooth. Interdental closures from both adjacent teeth had a significantly higher extension of the direct composite buildups than one-sided interdental closures (p=0.03). Patients with a history of prior tooth loss showed a significantly greater extension of direct composite buildups than patients without prior tooth loss (p=0.006). During the follow-up period, no restoration showed unfavorable events. The ...

Research paper thumbnail of Faserverstärkte Kompositbrücken

Zahnmedizin up2date, 2009

Research paper thumbnail of More conservative dentistry: Clinical long-term results of direct composite resin restorations

Quintessence international (Berlin, Germany : 1985), 2015

Current treatment protocols and recent developments in composite resin technology allow for exten... more Current treatment protocols and recent developments in composite resin technology allow for extended indication of direct composite resin restorations. This article presents clinical longterm observations of direct composite resin restorations indicated for primary and replacement therapy, repair restorations, direct crowns, and composite buildups for the correction of tooth form.

Research paper thumbnail of Mineral trioxide aggregate or calcium hydroxide direct pulp capping: an analysis of the clinical treatment outcome

Journal of endodontics, 2010

The use of mineral trioxide aggregate (MTA) might improve the prognosis of teeth after pulp expos... more The use of mineral trioxide aggregate (MTA) might improve the prognosis of teeth after pulp exposure. The treatment outcome of teeth after direct pulp capping, either with mineral trioxide aggregate (MTA) or calcium hydroxide (controls), was investigated, taking into account possible confounding factors. One hundred forty-nine patients treated between 2001 and 2006 who received direct pulp capping treatment in 167 teeth met the inclusion criteria. Treatment was performed by supervised undergraduate students (72%) and dentists (28%). Assessment of clinical and radiographic outcomes was performed by calibrated examiners 12-80 months after treatment (median, 27 months). One hundred eight patients (122 treated teeth) were available for follow-up (72.5% recall rate). A successful outcome was recorded for 78% of teeth (54 of 69) in the MTA group and for 60% of teeth (32 of 53) in the the calcium hydroxide group. The univariate analysis (generalized estimation equations model [GEE model] s...

Research paper thumbnail of Assessment of the reliability and validity of panoramic imaging for assessment of mandibular condyle morphology using both MRI and clinical examination as the gold standard

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2006

Research paper thumbnail of Proximal Contact Tightness Between Direct-composite Additions in the Posterior Dentition: An In Vitro Investigation

Operative Dentistry, 2012

Research paper thumbnail of The assessment of dentofacial esthetics in restorative dentistry: A review of the literature

Journal of the American Dental Association, 2012

The authors conducted a literature review to determine how dentofacial esthetics can be evaluated... more The authors conducted a literature review to determine how dentofacial esthetics can be evaluated in restorative dentistry and which quantifiable clinical parameters can be used for this assessment of dentofacial esthetics. The authors selected 35 studies that focused on assessment strategies for dental professionals. The primary inclusion criteria were intraoral and extraoral esthetic assessment methods and indexes or rating scales evaluating esthetics in restorative dentistry. The studies' protocols and assessment methods were heterogeneous. The authors grouped the studies into six categories according to topic: golden proportion, soft-tissue measurement, smile and smile line assessment, orofacial indexes and scales, incisor proportion and angulation, and facial esthetics. These categories included various esthetic parameters, including the smile line, lip line, incisal offset, location of dental and facial midline, incisor angulations and width to height ratios of the maxillary anterior teeth, gingival contour, and root coverage and papilla height. These parameters should be considered when providing dental treatment in the anterior area, as they allow for quantification and objective judgment. The findings of this review might increase interest in a comprehensive dental esthetic index that allows for objective quantification and intrastudy and interstudy comparison of dental treatment outcomes.

Research paper thumbnail of Fiber-reinforced composite fixed dental prostheses in the anterior area: A 4.5-year follow-up

The Journal of Prosthetic Dentistry, 2014

To obtain survival data on 32 fiber-reinforced fixed dental prostheses which were inserted in our... more To obtain survival data on 32 fiber-reinforced fixed dental prostheses which were inserted in our department and to rate the quality of these restorations on the basis of esthetic, biological, and functional parameters. Thirty-two patients with fiber-reinforced fixed dental prostheses were included in the study. The fiber frameworks were made of a polymer-monomer-preimpregnated continuous unidirectional glass fiber material. The survival times, failure events, and clinical parameters were recorded. Restorations in function without previous failure were classified as "Overall Survival". The classification "Functional Survival" was assigned in the event of minor failure and subsequent repair. Loss of the restoration was regarded as "Failure". The quality rating was performed using modified USHPS/Ryge criteria. The follow-up interval ranged from 2 to 64 months with a median follow-up time of 18.2 months. Twenty-four restorations were classified as "Overall Survival", seven were classified as "Functional Survival", and one was classified as "Failure". The overall survival at the median follow-up time was 74.4%. For the majority, the quality rating (USHPS/Ryge criteria) yielded clinically excellent results in all categories. No restoration was rated as insufficient or poor. Fiber-reinforced composite fixed dental prostheses provide sufficient stability and very good esthetic, biological, and functional performance in the case of specific clinical indications.

Research paper thumbnail of Influence of marginal and segmental mandibular resection on the survival rate in patients with squamous cell carcinoma of the inferior parts of the oral cavity

Journal of Cranio-Maxillofacial Surgery, 2004

Research paper thumbnail of Original and repair bond strength of fiber-reinforced composites in vitro

Dental Materials, 2014

A great benefit of FRC technology is that, in case of minor failure events, restorations can be r... more A great benefit of FRC technology is that, in case of minor failure events, restorations can be repaired or reinserted. However, various FRC materials are available, that differ in matrix composition and fiber pre-treatment. The aim of this investigation was, therefore, to evaluate original and repair bond strength of FRC materials. Five fully pre-impregnated, unidirectional FRCs were selected, one semi-interpenetrating polymer network FRC and four cross-linked-polymer FRCs. The primary endpoint was the evaluation of shear bond strength (SBS) between FRC and composite resin, which was performed by a universal testing machine. For each FRC specimens were divided into control (original SBS, resin to fresh FRC with oxygen inhibition layer (OIL), n=30) and test groups (repair SBS, resin to FRC after removal of OIL and adhesive infiltration, n=30). The cross-linked-polymer FRC GrandTec(®) (12.4±5.4 MPa) yielded the highest control SBS, followed by the semi-interpenetrating polymer network FRC (everStick(®), 9.2±3.5 MPa). With everStick(®), repair led to a significant increase in the test SBS (14.6±5.8 MPa, p=0.01). Control SBS was best with GrandTec(®) indicating that the material is superior in direct clinical application. Test SBS was significantly increased with everStick(®) which points at potential reparability and advantages in semi-direct or indirect fabrication of fiber-reinforced fixed partial dentures.

Research paper thumbnail of Relationship between microtensile bond strength and submicron hiatus at the composite–dentin interface using CLSM visualization technique

Research paper thumbnail of Analysis of the interdiffusion of resin monomers into pre-polymerized fiber-reinforced composites

Dental Materials, 2012

The aim of the study was to analyze the dissolving depth of adhesive resin monomers into pre-poly... more The aim of the study was to analyze the dissolving depth of adhesive resin monomers into pre-polymerized fiber-reinforced composites (FRC) with either a semi-interpenetrating polymer network (semi-IPN) or a cross-linked polymer (CLP) matrix. Five unidirectional FRCs were tested, including one semi-IPN FRC (everStick(®) C&B, StickTech, (ES)) and four CLP-FRCs (GrandTec(®), VOCO, (GT); Dentapreg(®), ADM, (DP); TenderFiber(®), Micerium, (TF); Splint-It(®), Pentron Clinical Technologies, (SI)). The FRCs were light-polymerized following manufacturers' instructions: the oxygen inhibition layers were removed and the adhesive resin (Optibond-FL(®), KerrHawe) was labeled with a fluorescent dye (Rhodamine-B-isothiocyanate), which was then applied to the FRCs (5 min) and light-polymerized (40s). Specimens were then prepared for confocal laser scanning microscopy. Three FRC strands per group were sectioned orthogonally to the direction of fibers, thus forming nine slices in each group. Four images were taken from each slice and the depths of adhesive penetration were measured in four sites per image (n=144 measurements per group). Dissolving depths were 17.28 (3.04) μm (ES), 12.58 (2.94) μm (SI), 7.57 (1.91) μm (TF), 3.27 (0.73) μm (DP) and 2.55 (0.63) μm (GT). Samples were normally distributed. Differences between groups were analyzed by ANOVA (PostHoc Scheffé) showing four subgroups (p=0.05). The infiltration layers detected were either continuous/homogenous (ES, TF, DP GT) or discontinuous/insular (SI). The adhesive resin monomers were able to diffuse significantly deeper into pre-polymerized semi-IPN specimens than into CLP materials. Semi-IPN specimens showed a homogenous and comparatively deeper layer of infiltration. The diffusion capabilities of secondary-IPN formation might increase the opportunity to establish a good bond between pre-polymerized FRC and new resin.

Research paper thumbnail of Bacterial Biofilm Composition in Caries and Caries-Free Subjects

Caries Research, 2013

Certain major pathogens such as Streptococcus mutans, Lactobacillus spp. and others have been rep... more Certain major pathogens such as Streptococcus mutans, Lactobacillus spp. and others have been reported to be involved in caries initiation and progression. Yet, in addition to those leading pathogens, microbial communities seem to be much more diverse and individually differing. The aim of this study, therefore, was to analyze the bacterial composition of carious dentin and the plaque of caries-free patients by using a custom-made, real-time quantitative polymerase chain reaction assay (RQ-PCR). The study included 26 patients with caries and 28 caries-free controls. Decayed tooth substance and plaque samples were harvested. Bacterial DNA was extracted and tested for the presence of 43 bacterial species or species groups using RQ-PCR. Relative quantification revealed that Propionibacterium acidifaciens was significantly more abundant in caries samples than were other microorganisms (fold change 169.12, p = 0.023). In the caries-free samples, typical health-associated species were significantly more prevalent. Unsupervised hierarchical cluster analysis showed a high abundance of P. acidifaciens in caries subjects and distinct but individually differing bacterial clusters in the caries-free subjects. The distribution of 11 bacteria allowed full discrimination between caries and caries-free subjects. Within the investigated cohort, P. acidifaciens was the only pathogen significantly more abundant in caries subjects. Cluster analysis yielded a diverse flora in caries-free subjects, whereas it was narrowed down to a small range of a few outcompeting members in caries subjects.

Research paper thumbnail of Cytotoxicity of coated and uncoated fibre-reinforced composites

Acta Odontologica Scandinavica, 2014

Currently, there are many fibre-reinforced composites (FRCs) available which differ in the type a... more Currently, there are many fibre-reinforced composites (FRCs) available which differ in the type and volume fraction of fibres, pre-treatment of fibres and matrix composition. The aims of this in vitro investigation were to determine whether there is a difference in biocompatibility of FRCs and if coating FRCs with resin composites influences their cytotoxic potential. Five different FRC materials were tested which were either uncoated or coated with flowable or viscous resin composite. Artificial saliva extracts were prepared according to USP-XXIII and ISO-10993 to determine cytotoxicity by testing cell viability and growth of primary human gingival fibroblasts (HGF) using MTT assay, LIVE/DEAD(®) assay and cell proliferation assay. The influence of eluates on fibres of the cytoskeleton was investigated by vimentin, tubulin and actinin immunostainings. A two-way ANOVA followed by Scheffe's post-hoc test, which included the factors FRC material and coating procedure, was performed to assess cytotoxicity. All extracts of FRC materials displayed minor cytotoxic potential on HGF cell viability, cell proliferation and integrity of the cytoskeleton. The type of FRC material significantly influenced cell viability (MTT assay) (p < 0.0001), whereas neither the presence of a coating nor the type of coating material resulted in altered cell viability. Distribution and organization of cytosolic fibres was not affected after HGF exposure to eluates. There is a lack of knowledge about the leaching behaviour of commonly available fully pre-impregnated FRCs and their interactions with coating materials. The coating of FRCs with resin composite materials did not impact biocompatibility.

Research paper thumbnail of Recontouring teeth and closing diastemas with direct composite buildups: A clinical evaluation of survival and quality parameters

Research paper thumbnail of The outcome of various cements in combination with titanium reconstruction plates after segmental resection of the mandible

British Journal of Oral and Maxillofacial Surgery, 2005