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Biomedical subjects

Adrian Lussi

Publications and source records attributed to Adrian Lussi.

At least 37 records · Page 2Linked to original sources
PubMed2005

[Tooth cleaning with different children's toothbrushes. A clinical study].

Toothbrushing is still the most effective method to maintain healthy conditions for teeth and gingiva. Over the last decades various manual and electric toothbrushes were developed to simplify oral hygiene and to shorten the duration of plaque removal. The aim of this study was to compare the effectiveness of two conventional toothbrushes and a three-headed toothbrush. Over a period of eight months 47 schoolchildren, aged between five and nine years, used different toothbrushes (one conventional medium-hard "Pingu", one conventional soft "CuraKid" and the three-headed toothbrush "Superbrush"). The study had a balanced, single blinded cross-over design. The children were assigned to one of two groups balanced with respect to the O'Leary Plaque Index. Following instructions, one group used a conventional brush during two months, the other group the"Superbrush". After two months they changed the brushes. After eight months the children had used all three brushes. The children were instructed to keep their usual oral hygiene habits. At the start and the end of each experimental period, the presence of plaque and gingival inflammation were recorded. A significant improvement of plaque removal and reduction of the gingival inflammation over eight months were noticed for all three brushes (P < 0.05). There were no significant differences in the cleaning efficiency between the three toothbrushes (P > 0.05). Significant improvements in plaque removal in children can be achieved following good brushing instructions regardless of the toothbrush design used.

Child↗
PubMed2005

Obturation quality after four years of storage using the non-instrumentation technique.

The aim of this in vitro study was to compare the sealing quality of three root canal filling materials after four years of ageing. Obturation with the non-instrumentation technique (NIT) was compared with cold lateral condensation of gutta-percha. Seventy-six canals were endodontically treated with traditional hand instrumentation and cold lateral condensation (control) whereas 77 canals were cleansed and obturated with NIT Three different sealers were used: AH 26, AH Plus and Apexit. After obturation, the teeth were stored for four years at 37 degrees C. Coronal dye penetration was evaluated after the teeth were made transparent. The teeth cleansed and filled with the new method showed significantly less dye penetration than the hand-instrumented teeth (p < 0.001). Within the hand-obturated group, Apexit showed significantly more dye penetration (4.7 +/- 0.71 mm) (p < 0.01) than AH Plus (1.83 +/- 0.57 mm) or AH 26 (1.16 +/- 0.4 mm). No significant differences were found within the NIT groups. This study showed NIT to produce root canal fillings with significantly less coronal leakage compared to the conventional technique after four years of storage in vitro.

Bismuth↗
PubMed2005

[Composite curing with new LED equipment].

Standardized holes ("cavities") measuring 4 mm in diameter and 8 mm in depth were prepared using plexiglass cubes. The following LCUs were tested: Astralis 10 Halogen light curing units (LCU), Bluephase, Elipar Freelight 2 and SmartLite LED LCUs. Each LCU was examined according to the following test conditions. Light exposure time of 20 s and 40 s. Polymerization directly onto the composite, with a distance of 4 mm or through a 3 mm thick ceramic disk, respectively. The composite Tetric Ceram (A3) was inserted in one batch and after a seven-day incubation period the cubes were sectioned into two halves and polished. Knoop microhardness was determined 100, 200, 500, 1000, 1500, 2500, 3000, 4000, 5000 and 6000 microm from the occlusal surface. The total degree of polymerization of a composite specimen for any given curing time and curing light was determined by calculating the area under the hardness curve. Multiple linear regression revealed that the distance of the light tip from the composite, curing time and the LCU had a significant association with the degree of polymerization (p < 0.001). The same pattern of cure profile was shown by all LCUs during the course of the test. The hardest composite was usually encountered around 200 microm from the occlusal surface. It was concluded that without irradiation through ceramic and a light tip close to the composite a light exposure time of 20 s will sufficiently polymerize an increment of at least 2 mm. Polymerization through ceramic needs a curing time of 40 s from each side.

Ceramics↗
PubMed2004

Use of a self-etching adhesive on previously etched intact enamel and its effect on sealant microleakage and tag formation.

AIM: This study verified the effects of a self-etching adhesive applied on pre-etched fissures (phosphoric acid 35%) on microleakage, penetration ability and tag formation of a fissure sealant. METHODS: 80 extracted sound human molar teeth were randomly divided into four groups and bisected in two equal parts, forming two subgroups, denominated A and B. Groups 1 and 2 were etched with phosphoric acid for 60 and 40s, respectively. Groups 3 and 4 were etched with phosphoric acid (40 and 20s, respectively) and afterwards treated with Xeno III (20s). All the procedures on sealant placement were performed under 90+/-2% relative humidity. The subgroups A and B were submitted to 1000 and 5000 thermal cycles, respectively. The samples were examined by light microscopy and by confocal laser scanning microscopy (CLSM) after sectioning. Microleakage, penetration ability, fissure type, tag formation quality and tag length were measured. RESULTS: Etching with phosphoric acid for 60s showed statistically significantly lower microleakage when compared to the other groups and significantly better tag formation quality and longer tags compared to 20s H(3)PO(4) plus Xeno III. Fissure type and number of thermal cycles were not significant factors on sealant microleakage. The penetration ability of the sealant in the fissure systems was not influenced by the treatment regimes. Shallow fissures showed a significant better tag formation than deep fissures. No significant difference in the prevalence of fissure types was seen among the groups. CONCLUSION: Etching fissures with phosphoric acid for 60s showed best results. The additional use of Xeno III did not improve fissure sealing under the conditions of this study.

Acid Etching, Dental↗
PubMed2004

Effect of topical applications of a chlorhexidine/thymol-containing varnish on fissure caries assessed by laser fluorescence.

The aim of this study was to monitor the effect of an antibacterial varnish using the readings of a caries-detecting device (DIAGNOdent) in fissures of young permanent molars. The material consisted of 32 healthy patients with a mean age of 14.1 years undergoing orthodontic treatment with fixed appliances. The inclusion criteria were presence of one homologous pair of 2nd upper or lower molars with clinically intact occlusal surfaces. A split-mouth study design was used in which the fissures were treated with either an antibacterial chlorhexidine/thymol-containing varnish or a placebo varnish every 6th week. The follow-up period was 42 weeks and laser fluorescence (LF) readings were carried out every 12th week. The mean LF values increased significantly (P < 0.05) after 24, 36, and 48 weeks compared to baseline following the placebo treatments but not after treatment with the active antibacterial varnish. During the study period, micro-cavities were diagnosed in two test-treated and five placebo-treated teeth. In conclusion, the results reinforce previous findings that frequent applications of a chlorhexidine/thymol-containing dental varnish might have a protective role in fissures of young permanent molars and that this could be monitored with a chair-side caries detecting LF device.

Adolescent↗
PubMed2004

White spot lesions around brackets: in vitro detection by laser fluorescence.

Demineralization around orthodontic brackets is one of the side-effects of orthodontic treatment. However, simple methods for its early detection, quantification and monitoring are lacking. Therefore, the aim of this investigation was to evaluate red laser-light induced fluorescence for measurement of demineralization around brackets in vitro, and whether an interference by the brackets should be expected. The site of measurement was standardized on 30 extracted human molars with natural demineralization on smooth surfaces. Fluorescence was measured (Diagnodent) on prebonded, etched, bonded with stainless steel brackets, and debonded enamel. We found no statistically significant difference in fluorescence after etching. After bonding, the fluorescence decreased by a median value of 0.5 compared to the prebonded and etched enamel. After debonding, the fluorescence increased by a median value of 0.5 and 1 compared with the prebonded and bonded conditions, respectively. The lack of agreement between prebonded and bonded enamel values (limits +12.4/-12.6) was possibly due to the difficulty in finding the same spot without the bracket (coefficient of repeatability = 9.1-10.8). In vitro, demineralization around brackets can be measured by laser fluorescence, but clinical studies are necessary.

Analysis of Variance↗
PubMed2004

["Molar-incisor hypomineralization"].

Hypocalcification of the enamel is the most common developmental disorder observed in teeth. The prevalence of this kind of hypomineralisation is about 10-19%. These molars are often referred to as cheese molars, because the lesions clinically resemble cheese in color and consistency. Other descriptions are: idiopathic enamel hypomineralisation in the permanent first molars, idiopathic enamel opacities in the permanent first molars, non fluoride enamel hypomineralisation in the permanent first molars, non-endemic mottling of enamel in the permanent first molars. Molar-Incisor Hypomineralisation is today the proposed expression for this disease. Occlusal surfaces of the first permanent molar are most commonly affected. The lesions are more frequent in the upper jaw than in the lower jaw. The incisors are affected to a lesser degree than the molars. Several aetiological factors can cause these defects. Some studies show a relation between intake of dioxins via mother's milk after prolonged breast feeding and developmental defects of the child's teeth. Because the ameloblasts are very sensitive to oxygen supply, complications involving oxygen shortages during birth or respiratory diseases such as asthma or bronchitis and pneumonia are discussed as further aetiological factors. Renal insufficiency, hypoparothyroidism, diarrhoea, malabsorption and malnutrition and high-fever diseases can be other reasons for the occurrence of these defects. Defective enamel can be a locus of lowered resistance for caries. Histologically there are areas of porosity of varying degrees. The affected teeth can be very sensitive to air, cold, warm and mechanical stimuli. Toothbrushing may create toothache in these teeth. We therefore suggest that these patients receive intensified prevention with fluoride varnish, a fissure sealing, GIZ, composits, stainless steel crowns or implants. In some cases an interdisciplinary approach with an orthodontist can result in the extraction of the molars in the age of 8 to 10 years.

Calcium↗
PubMed2004

[The balanced force and the GT-rotary technique in comparison with the non-instrumental technique (NIT)].

The aim of the study was to compare the cleansing effect of the latest modification of the non-instrumentation technique (NIT) to that of conventional instrumentation. The root curvature in 100 vital human molars was determined by a standardized X-ray procedure and the teeth were assigned to five groups with 20 teeth each with an equal distribution of the root curvature. The preparation methods were the Balanced Force technique and the GT Rotary technique. Each root was irrigated with 40 ml of 3% sodium hypochlorite. The other groups were irrigated by NIT during 2.5, 5 or 10 minutes, respectively. The remaining pulpal tissue was stained and the root canals were exposed longitudinally. The teeth were then evaluated using a microscope and an image analysis-system. The residual organic debris in the apical, middle and coronal sections of the root canals were assessed as a percentage of the corresponding total examined length. The cleansing effect of the NIT in the coronal and middle parts of the canal used for 5 and 10 minutes was significantly better (p < 0.05) compared to using the device for 2.5 minutes. The cleansing effect of the NIT in the coronal and middle parts of the canal used for 5 and 10 minutes was also significantly better (p < 0.05) compared to using the GT Rotary or Balanced Force techniques. Apically, the cleansing effect of the NIT used for 5 and 10 minutes and the GT Rotary technique was significantly better (p < 0.05) compared to using the Balanced Force technique or the NIT for 2.5 minutes. It was concluded that the cleansing effect of the latest modification of the Non-instrumentation Technology (NIT) was equivalent to or better than that of conventional instrumentation requiring significantly less time.

Dental Instruments↗
PubMed2004

Effects of application techniques and fissure types on the in vitro performance of two fissure sealants.

PURPOSE: To evaluate the effect of two materials, modified applications, moisture contamination and fissure types on the microleakage and penetration ability of fissure sealants. METHODS: 140 extracted human molar teeth were randomly assigned to 14 groups. The three following factors were tested: 1) two sealing materials (Concise and Tetric Flow), 2) four modified applications (cleaning with an air polishing device, etching with a vibration system, the use of drying agent and sealant application with a vibration system), 3) the procedures performed under two conditions (at ambient room condition and in a humidity chamber). Each tooth was subjected to thermal cycling (5000 cycles at 5-55 degrees C) and dye immersion (5% Methylene blue for 24 hours). After sectioning, microleakage, penetration ability and fissure type were examined. Multiple regression analyses were used for statistical analysis. RESULTS: The type of sealing materials and the modified applications were significantly associated with microleakage (P<0.001). The significant impacts on penetration ability were the fissure type, material and mode of application (P<0.004). CLINICAL SIGNIFICANCE: Concise showed significantly better performance than Tetric Flow. The non-invasive cleaning method with an air polishing system and the use of drying agent improved the quality of sealants. The greatest influence on penetration ability was the fissure type.

Bisphenol A-Glycidyl Methacrylate↗
PubMed2004

[Erosion in early school-age children].

The aim of the present study was to determine the prevalence, the severity and the distribution of erosive lesions in children, living in a rural region in Switzerland. A total of 42 children, aged between five and nine years, were examined. The following parameters were assessed: erosion on the facial, occlusal and oral tooth sites; flow rate and buffering capacity of resting saliva; oral hygiene and nutrition. The occurrence of erosive lesions was as follows: All children had one or more erosive lesions degree 1 (erosion within enamel) on occlusal surfaces and 20 (47.6%) of them showed at least one lesion of degree 2 (dentinal erosion). Already six (14.3%) of the examined children had one or more erosive lesions on occlusal surfaces of permanent teeth. Facial and oral erosions were scarce and only deciduous teeth were involved: Facial erosive lesions were examined in four (9.5%) (degree 1) and two (4.8%) (degree 2) of the children and oral lesions in three (7.1%) (degree 1) and one (2.4%) of them (degree 2). No statistically significantly impact of the following parameters on the occurence, distribution and degree of erosive lesions was found: age, gender, flow rate of resting saliva, buffering capacity, orale hygiene and nutrition. The results show clearly that erosive lesions can be detected already on deciduous teeth and the young permanent dentition is also involved. Early detection of the lesions is important. Preventive measures have to be initiated to stop or at least to diminish the erosive process.

Child↗
PubMed2004

[Erosion caused by gastric reflux in children. Discussion of etiology, clinical appearance and therapy in two cases].

Dental erosion is a disease occurring not only in adults but also in children. Thereby, deciduous and permanent teeth are involved. The cause of these lesions is an extended acid exposure due to extrinsic or intrinsic factors. Unlike caries, the erosive process occurs without involving bacteria. Main reasons are extensive consumption of erosive (soft) drinks and foodstuffs or gastrooesophageal reflux with regurgitation of gastric acid into the oral cavity. Often, the first signs of this disease are erosive lesions of the teeth and therefore dentists have an important role in early diagnosis. Two clinical cases are presented and the clinical diagnosis, the course and possible systemic and local preventive and therapeutic measures are discussed. Patients suffering from erosion can be treated successfully if the correct diagnosis and adequate preventive and therapeutic measures are performed.

Adolescent↗
PubMed2004

Prevention and minimally invasive treatment of erosions.

Erosive tooth wear is a multifactorial cumulative lifetime process, which may lead to tooth surface loss. Acids of intrinsic and extrinsic origin are the main etiological factors. This paper focuses on preventive measures and minimally invasive restorations. The application of high fluoride, time of toothbrushing as well as the intake of erosive foodstuffs or beverages should be optimized. Sealing of the tooth surfaces and small composite fillings are minimally invasive treatments for erosive lesions.

Beverages↗
PubMed2003

The effect of magnification on the iatrogenic damage to adjacent tooth surfaces during class II preparation.

OBJECTIVES: To determine the amount of damage to adjacent surfaces during cavity preparation of approximal box-cavities by using either no magnification or an individually adapted surgical telescope. MATERIALS AND METHODS: Nine dentists prepared in a mannequin head 4 approximal (class II) box-cavities without magnification using a high speed handpiece with lighting from a dental unit. At least 2 months later the test was repeated with a surgical telescope system with integrated light. The degree of damage the 72 adjacent surfaces suffered was determined. RESULTS: The average time needed to prepare one cavity was 14.9min without and 18.3min with magnification (p=0.01). Altogether, 29.7% of adjacent area were damaged when no surgical telescopes were used and 34.5% when surgical telescopes were applied (p>0.05). When the mesial-facing and distal-facing surfaces were analysed independently a statistically significant increase of damage was found on distal surfaces (p=0.03) when using surgical telescopes. Seventy surfaces (=97%) had a preparation trauma. CONCLUSIONS: Surgical telescopes do not decrease damage of adjacent tooth surfaces.

Adult↗
PubMed2003

Performance of visual inspection, electrical conductance and laser fluorescence in detecting occlusal caries in vitro.

The aim of this study was to compare visual inspection (VI) and electrical conductance (EC) and laser fluorescence (LF) measurements in detecting occlusal caries. VI was based on fissure discoloration and performed with the naked eye. EC was measured with the ECM device (Lode Diagnostic, Groningen, The Netherlands), and LF was assessed with the DIAGNOdent apparatus (KaVo, Biberach, Germany). In extracted human premolars and molars, clinically sound sites (D0-/D1-lesions), enamel caries (D2-lesions), and dentinal caries (D3-/D4-lesions) were identified using recommended cut-off values. Thereafter, the teeth were cut longitudinally and analyzed by scanning electron microscopy for verification of caries depth. Reproducibility of VI was good, that of EC and LF excellent. In identifying caries at both the enamel and dentin level, the sensitivities of VI and LF were significantly (p < 0.05) higher than that of EC, while EC was significantly (p < 0.05) more specific. The positive predictive values, however, did not exceed 43%. Improved diagnoses at the dentinal level were obtained, when EC and LF were used as an adjunct to VI and when cut-off values were raised. Thus, visual inspection relying exclusively on fissure discoloration seems to allow only proper identification of sound occlusal surfaces. In cases of discolored fissures, the appliance-based methods help to avoid false positive identification of dentinal caries. However, attainable reliabilities of diagnoses do not seem to exceed about 50% to 60%.

Adolescent↗
PubMed2002

Sparing of contralateral major salivary glands has a significant effect on oral health in patients treated with radical radiotherapy of head and neck tumors.

BACKGROUND: Has a conscious exclusion of the contralateral major salivary glands (parotid, submandibular, and sublingual glands) a significant impact on the milieu of the oral cavity (saliva flow, pH, buffer capacity, and colonisation with Streptococcus mutans) in patients with ENT tumors receiving radical radiotherapy? PATIENTS AND METHODS: 20 consecutive consenting patients with ENT tumors were evaluated once before, weekly during, and 6 weeks after the end of treatment in regard to saliva flow, ph, buffer capacity, and colonisation with Streptococcus mutans. In 13 patients the major salivary glands on both sides were included in the treated volume, in seven patients the treatment portals excluded consciously the contralateral major salivary glands. RESULTS: The stimulated saliva flow decreases already during the 1st week of radiotherapy, the decrease follows the dose exponentially; the saliva flow is further reduced in the weeks after the end of treatment. The effect is less pronounced in patients with sparing of contralateral major salivary glands. The majority of patients with unilateral sparing of the major salivary glands retain the baseline value of buffer capacity, whereas buffer capacity of all patients with inclusion of all major salivary glands is markedly reduced with 20 Gy already, without signs of recovery when treatment has stopped. With unilateral salivary gland sparing the pH always remains basic, in bilaterally irradiated patients the pH changes from a mean of 7.3 to 5.8 during treatment. The colonisation with Streptococcus mutans varies little in both groups during the radiotherapy; after the end of therapy, it is higher in bilaterally irradiated patients. CONCLUSIONS: The conscious arrangement of irradiation portals in order to spare contralateral major salivary glands in patients with radical radiotherapy of ENT tumors has a significant influence on the oral environment: the stimulated saliva flow is higher, the buffer capacity retains the baseline value, the saliva pH remains basic, and the colonisation with Streptococcus mutans is reduced.

Adult↗
PubMed2002

Comfort and discomfort of dental trauma splints - a comparison of a new device (TTS) with three commonly used splinting techniques.

The present experimental study compared four dental trauma splints in 10 volunteers. The evaluated splints included a wire-composite splint (WCS), a button-bracket splint (BS), a resin splint (RS), and the newly developed titanium trauma splint (TTS). All splints were bonded to the labial surfaces of the maxillary lateral and central incisors and left in place for 1 week. After splint removal, the next splint was placed after a 1-week rest period. The sequence of splint application was randomized for each individual. The following subjective parameters were assessed using a visual analogue scale: sensitiveness of splinted teeth, irritation of the gingival margin, irritation of the lips, impairment of speech, eating and oral hygiene. The results show that the application of BS leads to a significantly higher irritation of the lips and greater impairment of speech compared to other splints (P < 0.05). The RS leads to an increased and significantly higher irritation of the gingiva (P < 0.05) owing to a significant increase in cleaning difficulties (P < 0.05). In conclusion, WCS and TTS appear to be more accepted splints according to a subjective assessment by 10 volunteers.

Acrylic Resins↗
PubMed2002

Long-term stability of osseointegrated implants in augmented bone: a 5-year prospective study in partially edentulous patients.

This prospective clinical study evaluated the 5-year survival and success rates of 66 titanium implants placed in bone that had been previously augmented with autografts and nonresorbable barrier membranes. During the observation period, three patients with five implants dropped out of the study. None of the remaining 61 implants were lost during the follow-up period (implant survival rate of 100%). One implant exhibited a periimplant infection, whereas 60 implants were considered clinically successful at the 5-year examination, resulting in a 5-year success rate of 98.3%. It can be concluded that the clinical results of implants in regenerated bone are comparable to those of implants in nonregenerated bone.

Alveolar Ridge Augmentation↗