0000000000223519
AUTHOR
Bernd D'hoedt
Low level 809-nm diode laser-induced in vitro stimulation of the proliferation of human gingival fibroblasts
Background and Objective The authors investigated the effects of low level laser irradiation on the proliferation rate of human gingival fibroblasts (HGF) in vitro. Study Design/Materials and Methods HGF were obtained from gingival connective tissue explants and cultured under standard conditions. 110 cell cultures in their logarithmic growth phase were spread on 96-well tissue culture plates and were irradiated at energy fluences of 1.96–7.84 J/cm2. Another 110 cultures served as control. An 809-nm semiconductor laser operated at a power output of 10 mW in the cw-mode was used. The time of exposure varied between 75 and 300 seconds. Laser treatment was performed alternatively once, twice, …
Effectiveness of Self-Hypnosis on the Relief of Experimental Dental Pain: A Randomized Trial.
This randomized, controlled clinical trial evaluates the effectiveness of self-hypnosis on pain perception. Pain thresholds were measured, and a targeted, standardized pain stimulus was created by electrical stimulation of the dental pulp of an upper anterior tooth. Pain stimulus was rated by a visual analogue scale (VAS). The pain threshold under self-hypnosis was higher (57.1 ± 17.1) than without hypnotic intervention (39.5 ± 11.8) (p < .001). Pain was rated lower on the VAS with self-hypnosis (4.0 ± 3.8) than in the basal condition without self-hypnosis (7.1 ± 2.7) (p < .001). Self-hypnosis can be used in clinical practice as an adjunct to the gold standard of local anesthesia for pain m…
Low-level 809 nm GaAlAs laser irradiation increases the proliferation rate of human laryngeal carcinoma cells in vitro
The aim of the study was to investigate the effect of low-level 809 nm laser irradiation on the proliferation rate of human larynx carcinoma cells in vitro. Epithelial tumor cells were obtained from a laryngeal carcinoma and cultured under standard conditions. For laser treatment the cells were spread on 96-well tissue culture plates. Sixty-six cell cultures were irradiated with an 809 nm GaAlAs laser. Another 66 served as controls. Power output was 10 mW(cw) and the time of exposure 75–300 s per well, corresponding to an energy fluence of 1.96–7.84 J/cm2. Subsequent to laser treatment, the cultures were incubated for 72 h. The proliferation rate was determined by means of fluorescence acti…
Recognition of root canal orifices at a distance – a preliminary study of teledentistry
The remote recognition of root canal orifices was tested on 50 images of endodontically accessed teeth acquired with an intra-oral camera. The images were stored on a laptop computer and were presented to 20 observers who marked the visible canal orifices using software which stored the canal locations in standard files. The marked positions were verified on histological slices. In 87% of the cases, the canal locations were marked correctly. Inter-observer reliability depended on the location of the reviewed root canal (kappa = 0.44–0.77). The detection rate was related to the professional experience of the observers. The maximum proportion of accurate detections was found for the observer…
The Treatment of Anterior Dental Trauma
Anterior dental trauma is a common injury pattern of the dentoalveolar system in which appropriate first aid is important. When children and adolescents suffer an anterior dental trauma, the challenge is to preserve the tooth in this esthetically important area and minimize subsequent damage. Lack of treatment or improper treatment can lead to a lifelong need for dental care. There are many causes of anterior dental trauma. At the age of one and two years, it is mainly caused by falls when learning to walk. At preschool age, between two and six years, many such injuries are caused by falls resulting from lack of attention when engaging in physical play. The highest incidence of anterior den…
In vitro evaluation of the biocompatibility of contaminated implant surfaces treated with an Er : YAG laser and an air powder system
Abstract: Titanium platelets with a sand-blasted and acid-etched surface were coated with bovine serum albumin and incubated with a suspension of Porphyromonas gingivalis (ATCC 33277). Four groups with a total of 48 specimens were formed. Laser irradiation of the specimens (n=12) was performed on a computer-controlled XY translation stage at pulse energy 60 mJ and frequency 10 pps. Twelve specimens were treated with an air powder system. After the respective treatment, human gingival fibroblasts were incubated on the specimens. The proliferation rate was determined by means of fluorescence activity of a redox indicator (Alamar Blue® Assay) which is reduced by metabolic activity related to c…
Effect of diode laser irradiation on the attachment rate of periodontal ligament cells: an in vitro study.
The present study is part of a basic research program investigating the cellular effects of an 810 nm GaAlAs-diode laser on human periodontal tissues. The aim of the investigation was to evaluate the effects of laser treatment of root surface specimens on the attachment of periodontal ligament (PDL) cells in vitro.Root specimens were prepared from periodontally diseased teeth. PDL cells were obtained from human third molar ligaments. Cells were cultured under simple, standardized, and reproducible experimental conditions. One hundred fifty root specimens were scaled and root planed with curets followed by air-powder abrasive treatment; 75 were then lased and 75 served as controls. The irrad…
Efficacy of low level laser therapy in reducing postoperative pain after endodontic surgery-- a randomized double blind clinical study.
The aim of the study was to evaluate the effect of low level laser application on postoperative pain after endodontic surgery in a double blind, randomized clinical study. Fifty-two healthy adults undergoing endodontic surgery were included into the study. Subsequently to suturing, 26 patients had the operation site treated with an 809 nm-GaAlAs-laser (oralaser voxx, Oralia GmbH, Konstanz, Germany) at a power output of 50 mW and an irradiation time of 150 s. Laser treatment was simulated in further 26 patients. Patients were instructed to evaluate their postoperative pain on 7 days after surgery by means of a visual analogue scale (VAS). The results revealed that the pain level in the laser…
Efficacy of NaOCl/H2O2irrigation and GaAlAs laser in decontamination of root canals in vitro
Background and Objectives To investigate the bactericidal effect of an 809 nm semiconductor laser alone, and in combination with NaOCl/H2O2 irrigation in root canals in vitro. Study Design/Materials and Methods A total of 72 human single-rooted teeth extracted for periodontal reasons were included. The crowns were removed, the roots shortened to a length of 12 mm, and the canals enlarged up to an apical size of #50 file. The specimens were autoclaved and incubated with a suspension of Streptococcus sanguinis (ATCC 10556). Laser irradiation was performed on a PC-controlled XY translation stage. A 200 micron optic fiber was used. Twelve specimens were irradiated at a power output of 1.5, 3.0,…
Epulis granulomatosa as an oral manifestation of Klippel-Trénaunay syndrome
The Klippel-Trenaunay syndrome (KTS) was first described by Klippel and Trenaunay in 1900. It is characterized by the triad of hemihypertrophy of soft and hard tissue, naevus flammeus and venous varicosity in the affected area. Though all oral tissues may be affected, only 5% of KTS show manifestations in the head and neck region. Only three cases are described with an oral manifestation, showing gingival overgrowth clinically and histologically corresponding to a pyogenic granuloma. It is still uncertain whether the combination of gingival fibromatosis and KTS is significant or coincidental. We report about a 25-year-old patient with KTS and recidivous gingival fibromatosis, clinically and…
Incidence and predictive factors for perforation of the maxillary antrum in operations to remove upper wisdom teeth: prospective multicentre study.
Our aim was to evaluate the incidence of perforations of the sinuses and their related treatment after the removal of upper wisdom teeth depending on various anatomical and clinical variables.A total of 1057 upper wisdom teeth were removed under local anaesthetic in the departments of oral surgery at the Universities of Bonn, Düsseldorf, Frankfurt and Mainz, Germany. Data were collected with the help of an anonymised questionnaire dealing with information about the patients, and the position and stage of the development of teeth, as well as the occurrence and size of an oro-antral communication and its treatment.Of 465 extractions and 592 osteotomies of the upper third molars, 134 intervent…
Clinical evaluation of a modified marginal sulcular incision technique in endodontic surgery
The authors evaluated periodontal parameters following apical surgery using a new marginal sulcular incision. In 65 cases, surgical access was achieved by means of a sulcular incision technique without the involvement of the adjacent periodontia and the interproximal papillae and in 33 cases by means of a submarginal trapezoidal technique. Periodontal parameters (probing pocket depth, gingival recession, clinical attachment loss, and tooth mobility [periotest]) were recorded at baseline and after 6 months. Scar formation and the loss of papilla height were evaluated photographically. No significant changes in the attachment level and no loss of papilla height were found in either group. A s…
Randomized multicenter comparison of two coatings of intramobile cylinder implants in 313 partially edentulous mandibles followed up for 5 years
Intramobile cylinder (IMZ) implants with either of two coatings, hydroxyapatite (HA) or titanium plasma-flame (TPF), as distal abutments for combined tooth implant-supported restorations, were compared in 313 partially edentulous mandibles with respect to postprosthetical failure patterns and complication frequencies in a randomized multicenter clinical trial. Within the treatment protocols, the two coatings do not show evidence of different efficacy with respect to occurrence of postprosthetical integration deficiency (ID) or functional deficiency (FD). Statistical equivalence for an absolute effect of +/-15% in event-free survival could only be demonstrated for FD, not for ID, however. In…
Software for automated application of a reference-based method fora posterioridetermination of the effective radiographic imaging geometry
Objectives: Presentation and validation of software developed for automated and accurate application of a reference-based algorithm (reference sphere method: RSM) inferring the effective imaging geometry from quantitative radiographic image analysis. Methods: The software uses modern pattern recognition and computer vision algorithms adapted for the particular application of automated detection of the reference sphere shadows (ellipses) with subpixel accuracy. It applies the RSM algorithm to the shadows detected, thereby providing threedimensional Cartesian coordinates of the spheres. If the three sphere centres do not lie on one line, they uniquely determine the imaging geometry. Accuracy …
Intrapulpal temperature changes during root surface irradiation with an 809-nm GaAlAs laser
The aim of this study was to explore, in vitro, whether the irradiation of human root surfaces with a diode laser might induce nonphysiologic intrapulpal temperature elevations and, therefore, jeopardize pulp vitality.The pulps were removed from human maxillary and mandibular incisors extracted for periodontal reasons. The root canals were enlarged to an apical size #60 file. The teeth were radiographed with standard dental films and a millimeter grid to determine root thickness. The thickness of dentin between the root surface and the pulp in the irradiation areas was 1, 2, and 3 mm. To determine intrapulpal temperature changes during laser irradiation, 0.5-mm K-type thermocouples were ins…
Effect of diode laser irradiation on root surfaces in vitro.
The objective of this study was to evaluate possible morphological alterations of root surfaces after GaAlAs-diode laser (809 nm) irradiation under standardized in vitro conditions.Root specimens obtained from extracted periodontally diseased teeth were scaled and root planed with curettes followed by air-powder abrasive treatment prior to lasing. The variable parameters were power output (0.5-2.5 W) and exposure time (10-30 sec per specimen). Additionally, the effect of a saline solution and a human blood film on the root surface was investigated. The root segments were analyzed by means of a reflected light microscope. Photographs before and after irradiation were taken and evaluated. The…
Effect of diode laser irradiation on the survival rate of gingival fibroblast cell cultures
Background and Objective The present study is part of a basic research program investigating the cellular effects of the GaAlAs-diode laser with a wavelength of 810 nm on human periodontal tissues. The aim of the investigation was to evaluate the effects of the laser treatment on the survival rate of human gingival fibroblasts (HGF) in monolayer cell culture at different power settings and durations. Study Design/Materials and Methods HGF were obtained from a human gingival connective tissue explant. Cells were cultured on 24-well tissue culture plates. One hundred and thirty multi well cell cultures were laser treated. The variable parameters were power output (0.5–2.5 W) and exposure time…
On cone-beam computed tomography artifacts induced by titanium implants
Objectives: To briefly review the mathematical background of beam-hardening artifacts in cone-beam computed tomography (CBCT)-reconstruction and to investigate geometrical properties relevant for these reconstruction errors. By means of simulated and experimental results, beam-hardening effects caused by titanium implants are evaluated. Materials and methods: The geometrical and physical properties of the acquisition process of the projections used for 3D reconstruction are investigated and their effects on the CBCT images in the presence of titanium implants are derived. Beam-hardening effects are computed for a simplified polychromatic situation (three energy subsets of 80 and 110 kV) and…
Antibiotic susceptibility of cocultures in polymicrobial infections such as peri-implantitis or periodontitis: an in vitro model.
Although polymicrobial infections, such as peri-implantitis or periodontitis, were postulated in the literature to be caused by synergistic effects of bacteria, these effects remain unclear looking at antibiotic susceptibility. The aim of this study is to compare the antibiotic susceptibilities of pure cultures and definite cocultures.Laboratory strains of Aggregatibacter actinomycetemcomitans (Aa) (previously Actinobacillus actinomycetemcomitans), Capnocytophaga ochracea (Co), and Parvimonas micra (Pm) (previously Peptostreptococcus micros) were cultivated under anaerobic conditions, and their susceptibilities to 10 antibiotics (benzylpenicillin G, ampicillin, amoxicillin, ampicillin/sulba…
Temperature changes induced by 809-nm GaAlAs laser at the implant-bone interface during simulated surface decontamination
The aim of the study was to investigate temperature changes at the implant-bone interface during simulated implant surface decontamination with a 809-nm gallium-aluminium-arsenid (GaAlAs) semiconductor laser. Stepped cylinder implants with a diameter of 3.8 mm and a length of 11 mm with two different surfaces (sand-blasted and acid etched, and hydroxyapatite-coated) were inserted into bone blocks cut from freshly resected pig femurs. Access holes of 0.5 mm were drilled into the bone, to allow K-type thermocouples to contact periimplant bone in different parts of the cavity. An artificial periimplant bone defect provided access for laser irradiation in the coronal third. A 600-micrometer opt…
In vitro carious lesion detection on D-, E-, and F-speed radiographic films
Abstract Objectives To compare the accuracy in detection of interproximal natural carious lesions in vitro between Ultraspeed (D), Ektaspeed Plus (E), and Insight (F) radiographic films. Study design Ten observers indicated on a 5-point scale their confidence in detecting an interproximal lesion in 240 surfaces (120 extracted teeth) with noncavitated carious lesions. Truth was assessed microscopically from hemisections. The areas (Az) beneath receiver operating characteristic (ROC) curves were pairwise compared and used for a 2-way analysis of variance. Results Az values were significantly correlated with observers ( P = .002; Eta = 0.671) and film type ( P = .003; Eta = 0.412). E differe…
Effect of simulated CO2and GaAlAs laser surface decontamination on temperature changes in Ti-plasma sprayed dental implants
Background and Objective To investigate and compare temperature elevations at the implant-bone interface during simulated implant surface decontamination with a CO2 and a GaAlAs laser. Study Design/Materials and Methods Stepped cylinder implants (Frialit 2® Friadent GmbH, Mannheim, Germany) with a Titanium plasma sprayed surface were inserted into bone blocks cut from pig femurs. An artificial periimplant bone defect provided access for laser irradiation in the coronal third. Both lasers were operated at 1.0–2.5 W in the cw-mode. The bone block was placed into a 37°C water bath in order to simulate in vivo thermal conductivity and diffusitivity of heat. K-type thermocouples connected to a d…
Contrast perception in digitized panoramic radiographs compared with their film-based origin
Abstract Objectives. We sought to compare the visual image quality of film-based and digitized panoramic radiographs through use of a hole-containing test wedge. Study Design. An aluminum wedge containing 100 cells, of which 90 were given shallow holes, was exposed in the film-based Orthophos CD panoramic unit. Two radiographs subjectively exhibiting optimum contrast were selected. Films were digitized with a charge-coupled device flatbed scanner at 300 dpi. Films and digitized images were rated cellwise by 2 similar groups of 50 observers each with respect to spot perception. Results. The mean sensitivity was 0.26 ± 0.09 for film and 0.20 ± 0.07 for digitized images (P =.000), with a prono…
Mathematical analysis of projection errors in “paralleling technique” with respect to implant geometry
Abstract: “Standardized” radiographs acquired in paralleling technique serve for monitoring of marginal bone levels around endosseous implants. Under clinical conditions, parallel adjustment of the film to the implant is beset with great difficulties. A mathematical model matching clinical conditions was developed to evaluate projection geometry within an interval of clinically relevant angulations (± 10° from parallel position). Radiographs of two implants (Frialit 2, Friadent AG, Mannheim, Germany; Implant No. 1: ∅ 3.8 mm, length 10 mm; Implant No. 2: ∅ 6.5 mm, length 13 mm) were separately produced per angulation (2° increments) at one focus-object distance (FO=322.9 mm). Implant images …
Determination of projection geometry from quantitative assessment of the distortion of spherical references in single-view projection radiography
A method is introduced, inferring the three-dimensional (3-D) location from the 2-D radiographic shadow of an opaque spherical reference body of known radius by considering its elliptical distortion, the 2-D shadow location and a known source-to-receptor distance. Three noncollinear spheres fixed to a rigid object constitute all possible degrees of freedom, i.e., the entire 3-D imaging geometry. The method may be used (a) to determine the 3-D imaging geometry from a single 2-D view and (b) to correct for foreshortening of object distances coplanar with the plane defined by the sphere triplet. Apart from the mathematical background the article describes a small feasibility experiment, perfor…
B-mode versus A-mode ultrasonographic measurements of mucosal thickness in vivo
Abstract Objective: The objective of this study was to compare the measurement accuracy of A-mode and B-mode ultrasonographic assessments of palatal masticatory mucosal thickness in vivo. Study Design: Thickness of palatal masticatory mucosa in the molar region of 50 volunteers was measured once with a B-mode ultrasound device (10 MHz) combined with a standoff for intraoral applications. At identical reading points thickness was also assessed with an A-mode device (5 replicates) and by needle probing for determination of true thickness. Results: On average true thickness ranged between 2.9 and 3.3 mm (95% confidence intervals; median, 3.1 mm). B-mode ultrasonography overestimated truth by 0…
Bactericidal Effect of the Er:YAG Laser on Dental Implant Surfaces: An In Vitro Study
The aim of the in vitro study was to examine the bactericidal effect of an Er:YAG laser on common dental implant surfaces.Seventy-two titanium platelets with 3 different surfaces--sandblasted and acid-etched (SA), titanium plasma-sprayed (TPS), and hydroxyapatite-coated (HA)--were incubated with a suspension of Streptococcus sanguinis (ATCC 10556). Irradiation at pulse energies of 60 and 120 mJ and a frequency of 10 pps was performed on a computer-controlled XY translation stage. After laser treatment the specimens were sonicated and the bacterial growth examined by counting colony forming units on blood agar plates. Temperature elevations during irradiation were investigated using K-type t…
Clinical efficacy of semiconductor laser application as an adjunct to conventional scaling and root planing.
Background and Objectives: The aim of the in vitro study was to examine the clinical efficacy of semiconductor laser periodontal pocket irradiation as an adjunct to conventional scaling and root planing. Materials and Methods: Twenty-two healthy patients with a need of periodontal treatment (15 women, 7 men, mean age 45.0� 10.8 years) with at least four teeth in all quadrants, were included. All of them underwent a conventional periodontal treatment including scaling and root planing. Using a split mouth design, two randomly chosen quadrants (one upper and the corresponding lower one) were subsequently treated with an 809 nm GaAlAs laser operated at a power output of 1.0 Watt using a 0.6 mm…
Effect of low-level GaAlAs laser irradiation on the proliferation rate of human periodontal ligament fibroblasts: an in vitro study
Aim: The aim of this in vitro study was to evaluate a potential stimulatory effect of low-level laser irradiation on the proliferation of human periodontal ligament fibroblasts (PDLF). Materials and Methods: PDLF obtained from third molar periodontal ligaments were cultured under standard conditions and spread on 96-well tissue culture plates. Subconfluent monolayers were irradiated with an 809-nm diode laser operated at a power output of 10 mW in the continuos wave (cw) mode at energy fluences of 1.96‐7.84 Jcm ‐2 . The variable irradiation parameters were the time of exposure (75‐300 s per well) and the number of irradiations (1‐3). After laser treatment, the cultures were incubated for 24…
Temperature elevations in endosseous dental implants and the peri-implant bone during diode-laser-assisted surface decontamination
The aim of the study was to investigate temperature elevations in the implant surface and the peri-implant bone during simulated surface decontamination of endosseous dental implants with an 809 nm semiconductor laser. Stepped cylinder implants were inserted into bone blocks cut from resected pig femurs. An artificial peri-implant bone defect provided access for the irradiation of the implant surface. A 600 micron optic fiber was used at a distance of 0.5 mm from the implant surface. Power output varied between 0.5 and 2.5 W in the cw-mode. Power density was between 176.9 and 884.6 Wcm -2 . The bone block was placed into a 37 degree(s)C water bath in order to simulate in vivo thermal conduc…
Fast algorithm for detection of reference spheres in digital panoramic radiography.
In this paper, an algorithm for detection of reference spheres from digital panoramic radiographic images is presented. The proposed algorithm was tested on a database of 107 digital panoramic radiographic images which were used for dental diagnostics. Results show that the proposed method exhibits for detection of reference spheres, a sensitivity of 97.33% and specificity of 93.85%. Performance time differed between 0.55 and 2.36s depending on image size. The aim of this work was to provide a fast ellipse detection algorithm to reduce measuring time on preoperative implant planning by lowering the computational cost.