RESUMEN
OBJECTIVE: To analyze implant casts obtained from intraoral optical scanning and conventional impressions. MATERIALS AND METHODS: Ten optical scans (test) and ten conventional polyether impressions (control) were obtained from a two-implant reference model. Ten casts each were manufactured additively or from stone. All casts were digitized and virtually superimposed to the digital reference (trueness) applying a best-fit algorithm, and secondary analysis for intra-group comparisons (precision). The signed nearest neighbor distance of each surface point (FDI:24/26) was computed and deviations of the three-dimensional vectors (X,Y,Z) analyzed. The groups were compared with the Wilcoxon's rank sum test. RESULTS: The printed casts had mean deviations of 106.0µm and the stone casts 187.9µm compared to the reference. Controls had significantly higher deviations and dispersion (p⟨0.001). The printed casts showed mean intra-group deviations of 149.8µm and the stone casts 181.2µm without significant differences (p=0.162). There was no statistically significant difference in any of the vector analyses (X:p=0.105, Y:p=0.089, Z:p=0.123). CONCLUSION: Optical scanning seems to be an alternative to conventional impressions in terms of trueness and precision of implant master casts, simulating the scenario of a three-unit implant-supported fixed dental prosthesis. Digitally manufactured master casts might serve as reliable reference for the final restorations.
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Implantes Dentales , Técnica de Impresión Dental , Diseño Asistido por Computadora , Materiales de Impresión Dental , Imagenología Tridimensional , Modelos DentalesRESUMEN
Scientific data analysing color masking abilities of chairside CAD/CAM materials is lacking. The purpose of this in-vitro study was to evaluate the thickness and shade influence of three materials on their optical behaviour. Three materials: a) LD: Lithium disilicate glass ceramic (Emax, Ivoclar Vivadent), b) LDS: Lithium-disilicate-strengthened aluminosilicate glass ceramic (N!ce, Straumann) and c) RNC: Resin Nanoceramic (Lava Ultimate, 3M ESPE) were polished in different shades (A1,A2,A3) and thicknesses (0.1- 1.2mm). Specimens (N=108; n=36 per group) (12x12x1mm3) were positioned on resin composite base (Clearfil AP-X, Kuraray) in shade A3. Spectrophotometric measurements were performed and the parameters thickness, shade and material were analysed using three-way ANOVA, and pairwise T-tests (P-values ⟨ 0.05). Both the shade (p⟨0.001) and the interaction of material in correlation to thickness (p⟨0.001) were significant. Shade value A1-A3 comparisons were significant A1 vs. A2 (p=0.045); A2 vs. A3 (p=0.002); A1 vs. A3 (p⟨0.001)). A significant correlation of the material and thickness was observed when comparing LD and LDS (p=0.007) at the thickness of 0.1-0.4 mm. Masking abilities were influenced by material and thickness choice. Reinforced glass ceramics showed the best results in the smallest thickness tested (0.1-0.4 mm). LDS could be considered as an advantageous alternative in minimal-invasive cases.
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Cerámica , Porcelana Dental , Color , Diseño Asistido por Computadora , Ensayo de MaterialesRESUMEN
To evaluate fracture resistance of occlusal veneers made of glass-ceramic and zirconia with and without fatigue. Occlusal overlays (N=80; n=10 per group) were milled out of CAD/CAM materials, namely: a)LD:Lithium disilicate glass ceramic, b)LDS:Lithium-disilicate- strengthened aluminosilicate glass ceramic, c)ZLT:Zirconium dioxide ceramic and d)ZMT:Zirconium dioxide ceramic. The overlays were cemented on polymeric duplicates, randomly distributed to aging or non-aging conditions and loaded until fracture. Ultimate catastrophic failure strength(Fmax) and Initial crack formation load(Finitial) values were analysed using two-way ANOVA. For Finitial, material type and aging and their interaction resulted in significant values (p =⟨0.001). Finitial mean±SD values ranged from ZMTa (593 N ±205 N) to LDSb (118 N ±42 N). As for Fmax, the material type significantly affected the outcome (p⟨0.001), while aging type did not show an influence (p=0.795). The non-aged Fmax specimens values presented were: LDSa (877 N ±253 N)⟨LDa (2029 N ±412 N)⟨ZLTa (2049 N ±379 N)⟨ZMTa (2144 N ±333 N), LDSa being significantly lower (p⟨0.001). The aged Fmax values were: LDSb (1313 N ±599 N)⟨ ZLTb (1715 N ±453 N)⟨ZMTb (2018 N ±300 N)⟨LDb (2134 N ±289 N). LDS yielded significantly lower Fmax values without and non-significant less favourable results with aging. The mechanical properties following aging and lack of additional firing makes LDS an interesting restorative material for clinical application.
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Porcelana Dental , Coronas con Frente Estético , Cerámica , Diseño Asistido por Computadora , Análisis del Estrés Dental , Ensayo de Materiales , CirconioRESUMEN
Patients' esthetic expectations are increasing, and the options of the prosthetic pathways are currently evolving. The objective of this randomized multicenter clinical trial was to assess and compare the esthetic outcome and clinical performance of anterior maxillary all-ceramic implant crowns (ICs) based either on prefabricated zirconia abutments veneered with pressed ceramics or on CAD/CAM zirconia abutments veneered with hand buildup technique. The null hypothesis was that there is no statistically significant difference between the 2 groups. Forty implants were inserted in sites 14 to 24 (FDI) in 40 patients in 2 centers, the Universities of Bern and Geneva, Switzerland. After final impression, 20 patients were randomized into group A, restored with a 1-piece screw-retained single crown made of a prefabricated zirconia abutment with pressed ceramic as the veneering material using the cut-back technique, or group B using an individualized CAD/CAM zirconia abutment (CARES abutment; Institut Straumann AG) with a hand buildup technique. At baseline, 6 mo, and 1 y clinical, esthetic and radiographic parameters were assessed. Group A exhibited 1 dropout patient and 1 failure, resulting in a survival rate of 94.7% after 1 y, in comparison to 100% for group B. No other complications occurred. Clinical parameters presented stable and healthy peri-implant soft tissues. Overall, no or only minimal crestal bone changes were observed with a mean DIB (distance from the implant shoulder to the first bone-to-implant contact) of -0.15 mm (group A) and 0.12 mm (group B) at 1 y. There were no significant differences at baseline, 6 mo, and 1 y for DIB values between the 2 groups. Pink esthetic score (PES) and white esthetic score (WES) values at all 3 examinations indicated stability over time for both groups and pleasing esthetic outcomes. Both implant-supported prosthetic pathways represent a valuable treatment option for the restoration of single ICs in the anterior maxilla ( ClinicalTrials.gov NCT02905838).
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Diseño Asistido por Computadora , Coronas , Pilares Dentales , Diseño de Implante Dental-Pilar/métodos , Prótesis Dental de Soporte Implantado/métodos , Estética Dental , Circonio , Adulto , Fracaso de la Restauración Dental , Femenino , Humanos , Masculino , Resultado del TratamientoRESUMEN
AIM: To investigate the association of the Periodontal Risk Assessment (PRA) model categories with periodontitis recurrence and tooth loss during supportive periodontal therapy (SPT) and to explore the role of patient compliance. MATERIAL AND METHODS: In a retrospective cohort, PRA was performed for 160 patients after active periodontal therapy (APT) and after 9.5 +/- 4.5 years of SPT. The recurrence of periodontitis and tooth loss were analysed according to the patient's risk profile (low, moderate or high) after APT and compliance with SPT. The association of risk factors with tooth loss and recurrence of periodontitis was investigated using logistic regression analysis. RESULTS: In 18.2% of patients with a low-risk profile, in 42.2% of patients with a moderate-risk profile and in 49.2% of patients with a high-risk profile after APT, periodontitis recurred. During SPT, 1.61 +/- 2.8 teeth/patient were lost. High-risk profile patients lost significantly more teeth (2.59 +/- 3.9) than patients with moderate- (1.02 +/- 1.8) or low-risk profiles (1.18 +/- 1.9) (Kruskal-Wallis test, p=0.0229). Patients with erratic compliance lost significantly (Kruskal-Wallis test, p=0.0067) more teeth (3.11 +/- 4.5) than patients compliant with SPT (1.07 +/- 1.6). CONCLUSIONS: In multivariate logistic regression analysis, a high-risk patient profile according to the PRA model at the end of APT was associated with recurrence of periodontitis. Another significant factor for recurrence of periodontitis was an SPT duration of more than 10 years.
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Periodontitis/prevención & control , Medición de Riesgo/métodos , Pérdida de Diente/prevención & control , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Modelos Biológicos , Índice Periodontal , Periodontitis/clasificación , Periodontitis/complicaciones , Periodontitis/terapia , Recurrencia , Estudios Retrospectivos , Estadísticas no Paramétricas , Pérdida de Diente/etiología , Resultado del Tratamiento , Adulto JovenRESUMEN
AIM: The aim of this study was to assess the marginal fit of crowns on the Straumann (ITI) Dental Implant System with special consideration of different casting dental materials. MATERIAL AND METHODS: Sixty porcelain-fused-to-metal crowns were fabricated: 18 crowns on standard cone abutments with an impression cylinder, partially prefabricated analogs, no coping and screw-retained (A); 18 crowns on solid abutments without an impression device, no analogs, no coping and cemented (B); and 18 crowns on solid abutments using an impression transfer cap, an analog with a shoulder, no coping and cemented (C). In each group, six crowns were made on epoxy mastercasts (Bluestar), six on synthetic plaster (Moldasynt) and six on super hard stone (Fujirock). Six additional crowns were fabricated with the transversal screw retention system onto the Octa system with impression transfer caps, metal analogs, gold copings and screw-retained (D). Impregum was used as impression material. Crowns of B and C were cemented with KetacCem. Crowns of A and D were fixed with an occlusal screw torqued at 15 N cm. Crowns were embedded, cut and polished. Under a light microscope using a magnification of x 100, the distance between the crown margin (CM) and the shoulder (marginal gap, MG) and the distance between the CM and the end of the shoulder (crown length, CL) was measured. RESULTS: MGs were 15.4+/-13.2 microm (A), 21.2+/-23.1 microm (B), 11+/-12.1 microm (C) and 10.4+/-9.3 microm (D). No statistically significantly differences using either of the casting materials were observed. CLs were -21.3+/-24.8 microm (A), 3+/-28.9 microm (B), 0.5+/-22 microm (C) and 0.1+/-15.8 microm (D). Crowns were shorter on synthetic casting materials compared with stone casts (P<0.005). CONCLUSIONS: CMs fit precisely with both cemented and screw-retained versions as well as when using no, partial or full analogs.
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Coronas , Pilares Dentales , Implantes Dentales , Retención de Prótesis Dentales/métodos , Prótesis Dental de Soporte Implantado , Cementación , Técnica de Impresión Dental , Adaptación Marginal Dental , Retención de Prótesis Dentales/instrumentación , Cementos de Ionómero Vítreo , Óxido de Magnesio , Aleaciones de Cerámica y Metal , Modelos Dentales , Cemento de Policarboxilato , Ajuste de Prótesis , Torque , Óxido de ZincRESUMEN
AIM: The aim of the present study was to evaluate the effect of root canal treatment on periapical lesions by conventional and subtracted digital radiographic images of clinical cases. METHODOLOGY: Eleven patients who exhibited clinical or radiological signs of periapical pathology received root canal treatment. Periapical radiographs were obtained immediately postoperatively and recall radiographs at intervals of 3, 6, 9 and 12 months postoperatively were obtained. Identical exposure geometry was maintained. From the standardized radiographs digitized images were produced. Four experienced practitioners interpreted the radiographs and the digitized images. They assessed 59 pairs of images projected at random using a slide projector. On the left side, there was a reference image with no lesion, and on the right an image either with or without a lesion. Each reader was asked to rate each pair of images on a three-point scale: yes, absolutely sure that gain or loss was present; uncertain, if there was gain or loss; no, absolutely sure that no gain or loss was present. There was no time limit for each decision. Inter- and intra-examiner agreement was analyzed using the kappa-statistic for the diagnosis of periapical bone density changes in the periapical region at the different time points either in conventional pairs of radiographs or using digital subtraction images. RESULTS: The inter-examiner agreement (P < 0.001) and the intra-examiner agreement (P = 0.02) when digital pictures where evaluated were significantly higher than with conventional radiographs. CONCLUSIONS: A highly significantly better observer agreement was achieved by digital subtraction radiography during the evaluation of the outcome of root canal treatment on periapical lesions.
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Pérdida de Hueso Alveolar/diagnóstico por imagen , Evaluación de Resultado en la Atención de Salud/métodos , Radiografía Dental Digital , Tratamiento del Conducto Radicular , Técnica de Sustracción , Adulto , Anciano , Pérdida de Hueso Alveolar/etiología , Color , Medios de Contraste , Enfermedades de la Pulpa Dental/complicaciones , Enfermedades de la Pulpa Dental/terapia , Humanos , Persona de Mediana Edad , Variaciones Dependientes del ObservadorRESUMEN
The present study analyzed the relationship between periodontal health adjacent to filled and unfilled tooth sites in young men (recruits). The status of oral health of 419 Swiss army recruits, aged 19 to 20 years was assessed by determining Plaque Index (PI), Retention Index (RI) and Gingival Index (GI) as well as Pocket Probing Depth (PPD) and Probing Attachment Loss (PAL). In addition, the level of alveolar bone was measured using digitized bite-wing radiographs with an enlargement of 4.5x. Filling margins were assessed and the distance between the alveolar bone crest and the cemento-enamel junction (CEJ) measured to the nearest one tenth of a millimeter. These data were compared with the clinical parameters. A total of 8'050 sites were examined. 765 or 9.5 of the sites in the posterior area were filled. 119 of them showed filling overhangs larger than 0.2 mm. Thus, 1.5 % of the examined sites had a significant overhanging margin. All clinical parameters had greater values at filled than at unfilled sites. The differences were statistically not significant. Even the sites with margins overhanging more than 0.8 mm (n=14) did not show significantly different parameters compared to unfilled sites. The comparison with a similar study involving recruits 11 years earlier assessed that the recruits of 1996 had less and smaller filling overhangs. This, in turn, means that, in Switzerland restorative dentistry in young males has been markedly improved during the 1980's and 1990's.
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Adaptación Marginal Dental , Restauración Dental Permanente/normas , Personal Militar , Salud Bucal , Índice Periodontal , Adulto , Factores de Edad , Interpretación Estadística de Datos , Humanos , Masculino , Factores Sexuales , SuizaRESUMEN
The purpose of this study was to investigate the clinical, microbiological and radiological effects of peri-implantitis therapy by local delivery of tetracycline. In 25 partially edentulous patients, 30 implants with radiographic evidence of circumferential bone loss, and peri-implant probing depths > or =5 mm were treated with polymeric tetracycline HCl-containing fibers. Clinical and microbial parameters were recorded at baseline, and 1, 3, 6, and 12 months (M) after treatment. Standardized radiographs were obtained at baseline, M3, and one year after treatment. Two patients were discontinued from the study after 180 days because of persisting active peri-implantitis with pus formation. The remaining subjects showed a significant decrease of mean peri-implant probing depth from 6.0 to 4.1 mm (M1, P<0.001), which was maintained over 12 months. In comparison to baseline, the bleeding tendency was significantly reduced after one month, and thereafter (P<0.001). No significant recession of the mucosal margin was noted. The radiologically determined distance from the shoulder of the implant to the bottom of the bony defect decreased slightly, but not significantly, from 5.2 to 4.9 mm. At M1, M3 and M6, mean total anaerobic cultivable bacterial counts were significantly lower than at baseline (P<0.001). A significant decrease in frequency of detection was noted for Prevotella intermedia/nigrescens, Fusobacterium sp., Bacteroides forsythus, and Campylobacter rectus (P<0.01). Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Eikenella corrodens had very low baseline frequencies that could not be significantly suppressed further. In conclusion, therapy of peri-implantitis by local delivery of tetracycline had a positive effect on clinical and microbiological parameters.
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Antibacterianos/administración & dosificación , Materiales Biocompatibles/administración & dosificación , Celulosa/administración & dosificación , Implantes Dentales/efectos adversos , Sistemas de Liberación de Medicamentos , Periodontitis/tratamiento farmacológico , Periodontitis/etiología , Tetraciclina/administración & dosificación , Administración Tópica , Pérdida de Hueso Alveolar/diagnóstico por imagen , Pérdida de Hueso Alveolar/etiología , Bacterias Anaerobias/efectos de los fármacos , Recuento de Colonia Microbiana , Implantes Dentales/microbiología , Femenino , Bacterias Gramnegativas/efectos de los fármacos , Humanos , Modelos Lineales , Masculino , Periodontitis/microbiología , Infecciones Relacionadas con Prótesis/tratamiento farmacológico , Radiografía , Estadísticas no ParamétricasRESUMEN
The aim of this study was to compare the frequency of biological and technical complications with fixed partial dentures (FPDs) on implants, teeth and as mixed tooth-implant supported FPDs over 4 to 5 years of function. All implants belonged to the ITI Dental Implant System. Group I-I (implant FPD) included 33 patients with 40 FPDs, group T-T (tooth FPDs) 40 patients with 58 FPDs, group I-T (mixed tooth-implant FPDs) 15 with 18 FPD. Of the bridge abutments 144 were teeth and 105 were implants. The median number of units replaced by the FPDs was 3 (range 2-14). The mean age of the patients was 55.7 years (range 23-83). Complete failures resulted in the loss of one FPD in each group. Two implants were lost due to fracture secondarily to development of a bone defect. One tooth had a vertical fracture and 1 tooth was lost due to periodontitis. Biological complications (peri-implantitis, PPD > or = 5 mm and BOP+) occurred at 9.6% (10) of the implants. This number was, however, reduced to 5% if the threshold for definition of peri-implantitis was set at PPD > or = 6 mm and BOP+. Biological complications occurred in 11.8% (17) of the abutment teeth (NS compared to implants); 2.8% (4) had secondary caries, 4.9% (7) endodontic problems and 4.1% (6) had periodontitis (PPD > or = 5 mm, BOP+). Ten out of 32 patients with a general health problem indicated a biological complication, whereas 9 out of 53 patients with no general health problem had a biological complication (chi 2: NS). Statistically significantly more technical complications were found in FPDs on implants (chi 2, P < or = 0.05). The technical complications were associated with bruxism. Out of 10 bruxers 6 had a technical complication whereas 13 out of 75 non-bruxers had such a complication (chi 2 < or = 0.01). Extensions were associated with more technical complications (13 out of 35 with extensions versus 9 out of 81 without). In conclusion, favourable clinical conditions were found at tooth and implant abutments after 4-5 years of function. Loss of FPD over 4-5 years occurred at a similar rate with mixed, implant or tooth supported reconstructions. Significantly more porcelain fractures were found in FPDs on implants. Impaired general health status was not significantly associated with more biological failures but bruxism as well as extensions were associated with more technical failures.
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Implantes Dentales , Prótesis Dental de Soporte Implantado , Fracaso de la Restauración Dental , Prótesis de Recubrimiento , Dentadura Parcial Fija , Adulto , Anciano , Anciano de 80 o más Años , Pérdida de Hueso Alveolar/etiología , Bruxismo/complicaciones , Distribución de Chi-Cuadrado , Pilares Dentales/efectos adversos , Caries Dental/etiología , Implantación Dental Endoósea/efectos adversos , Implantes Dentales/efectos adversos , Porcelana Dental , Prótesis Dental de Soporte Implantado/efectos adversos , Enfermedades de la Pulpa Dental/etiología , Diseño de Dentadura/efectos adversos , Prótesis de Recubrimiento/efectos adversos , Dentadura Parcial Fija/efectos adversos , Femenino , Estudios de Seguimiento , Hemorragia Gingival/etiología , Humanos , Masculino , Persona de Mediana Edad , Bolsa Periodontal/etiología , Periodontitis/etiología , Factores de Riesgo , Estrés Mecánico , Fracturas de los Dientes/etiología , Pérdida de Diente/etiologíaRESUMEN
The aim of this study was to develop and test in vitro an opto-electronic positioning device for serial direct digital images of oral structures, i.e. to associate direct digital imaging with the principles of computer-aided surgery. This system registered positions of infrared light emitting diodes (LED) on carriers, establishing local coordinate systems. With LED markers attached on the sensor holder, the X-ray tube and a fix reference, the opto-electronic camera (Optotrak) registered the geometric source/detector relation. A specially designed tracking and guidance software was developed which enabled the operator to reposition the X-ray source. A graphical user interface guided the operator in aligning 2 circles to the reference axis, one indicating the origin of the beam, the other its tip. In addition, depth control was provided. An in vitro calibration was performed. A sensor holder/bite block carried the Sens-A-Ray sensor with a hair-cross. In front of the object a second hair-cross was fixed. A steel ball fixed to the center of the X-ray cone allowed to verify the alignment. The mean angulation error in the vertical plane was 0.06 degrees and 0.04 degrees in the horizontal one. Translation mean errors were small and ranged between -0.02 mm and 0.37 mm. The translation in the Z axis is negligible. This resulted in pairs of images suitable for digital subtraction. Although still in an experimental state, the results showed that opto-electronic navigation was useful to standardize projection geometry without any mechanical link and to achieve digital subtraction images based on direct digital imaging.
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Boca/diagnóstico por imagen , Radiografía Dental Digital/instrumentación , Cirugía Bucal/instrumentación , Terapia Asistida por Computador/instrumentación , Diseño de Equipo , Humanos , Boca/cirugía , Óptica y Fotónica/instrumentación , Técnica de Sustracción/instrumentaciónRESUMEN
In the present report a repair set to retrieve fractured abutments remaining in the implants of the ITI Dental Implant System is presented. In 1 case in which such fractures occurred, the repair set was successfully applied. After removal of all particles of the fractured prosthetic abutments and recutting the threads, new abutments were used, and the original suprastructure could be reinserted. The causes for such technical failures are discussed considering the relatively sparse information in the literature on that topic.
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Pilares Dentales , Reparación de Prótesis Dental , Fracaso de la Restauración Dental , Remoción de Dispositivos/métodos , Implantes Dentales , Dentadura Parcial Fija , Humanos , Persona de Mediana EdadRESUMEN
The aim of this study was to evaluate a clinical and a microbiological test for monitoring tissue condition during supportive periodontal therapy (SPT) and to compare their diagnostic characteristics at implant and tooth sites. Twelve female (age: 37-72 years) and 7 male patients (age: 26-83 years) were evaluated in this study on the basis of availability to follow a rigid SPT program. Patients had received a complete periodontal examination at 1 and 5 years after implant placement. This included standardized radiographs obtained at implants and matching control teeth. One implant site and one tooth site per patient were followed during the last 2 years of the SPT program. At each recall visit microbiological samples were analyzed according to DNA/RNA analysis identifying periodontal pathogens (IAI Pado Test 4.5, Institute for Applied Immunology, Zuchwil, Switzerland). Presence or absence of bleeding on probing at these sites was also noted using a standardized probing force of 0.25 N (Audio Probe, ESRO, Thalwil ZH, Switzerland). The percentage number of recall visits with positive bacteriological test results and positive BOP scores were calculated. Disease progression at the sites was defined if the annual increase in probing depth was > or = 0.5 mm/year (2.5 mm in 5 years) or if the annual decrease in CADIA values (Computer Assisted Densitometric Image Analysis) was more than -0.7 per year (-3.5 in 5 years). Changes below these values were considered as negative test results indicating stability of the sites. The diagnostic characteristics (sensitivity, specificity, positive and negative predictive values) of BOP and microbiological tests alone or in combination were then calculated using two-by-two tables. By application of increasing thresholds of BOP frequencies set for definition of positive test outcome (BOP > or = 10% > or = 20% > or = 25% > or = 50% > or = 75% > or = 90% or the combined BOP > or = 75%, but DNA positive > or = 10%, > or = 25% > or = 34% > or = 50% > or = 67% > or = 90%) receiver operator characteristics curves (ROC) were constructed for teeth and implants. The areas under the ROC curves were calculated and compared by means of chi-square tests. The results indicated statistically significant better diagnostic characteristics of both tests at implants compared to teeth. The inclusion of an additional microbiological test significantly enhanced the diagnostic characteristics of BOP alone at teeth as well as at implants.
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Implantes Dentales/microbiología , Periodontitis/prevención & control , Periodoncio/microbiología , Adulto , Anciano , Anciano de 80 o más Años , Aggregatibacter actinomycetemcomitans/crecimiento & desarrollo , Área Bajo la Curva , Técnicas Bacteriológicas , Distribución de Chi-Cuadrado , ADN Bacteriano/análisis , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Hemorragia Gingival/microbiología , Hemorragia Gingival/prevención & control , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Bolsa Periodontal/microbiología , Bolsa Periodontal/prevención & control , Periodontitis/microbiología , Porphyromonas gingivalis/crecimiento & desarrollo , Valor Predictivo de las Pruebas , Prevotella intermedia/crecimiento & desarrollo , ARN Bacteriano/análisis , Curva ROC , Sensibilidad y Especificidad , Treponema/crecimiento & desarrolloRESUMEN
PURPOSE: The aim of this study was to propose a new clinical diagnostic rating index for secondary caries lesions at crown margins and to correlate this index with histologic evaluations. MATERIALS AND METHODS: Based on criteria for the evaluation of root caries, a modification of secondary caries lesions at the crown margin (SC index) was applied; the lesion characteristics were described as SCO to SC4. A total of 16 crowned teeth exhibiting secondary caries were randomly selected. The teeth were rated and grouped according to their clinical SC grades (SC1 to SC4). After embedding in Technovit, the teeth were serially sectioned and histologic caries scores were given for each section. RESULTS: Fifty-two percent of the prepared margins were in cementum/dentin. Crown margins with no caries lesions were mainly found in teeth clinically rated as SC1 and exhibiting localized discolorations, whereas deep lesions were found histologically at teeth rated SC4. The nonparametric test according to Spearman's rank correlation coefficient (rho) confirmed a highly significant correlation between the clinical SC index and the histologic evaluation (rho = 0.87, 95% confidence interval = 0.67 to 0.96, P < 0.01). SC1 discolorations overestimate caries lesions, whereas SC2 and SC4 lesions are well correlated to the percentage of histologically evaluated caries extension into all sections of a tooth. Lesions rated SC3 demonstrated a high variability of caries penetration into the dentin. CONCLUSION: The depth of discolorations and circular lesions is clinically not well predictable. Clinical diagnosis for localized superficial caries and deep caries lesions at the crown margin correlated well with the histologic caries rating.
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Coronas/efectos adversos , Caries Dental/diagnóstico , Adulto , Caries Dental/etiología , Caries Dental/patología , Progresión de la Enfermedad , Humanos , Persona de Mediana Edad , Recurrencia , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Estadísticas no Paramétricas , Cuello del DienteRESUMEN
PURPOSE: The aim of the present clinical study was to analyze the long-term treatment outcome of fixed partial dentures (FPD) with cantilevers. MATERIALS AND METHODS: Ninety-two patients with 115 cantilever FPDs on 239 abutment teeth were examined. Immediately following cementation, radiographs of the abutment teeth were obtained. At the follow-up examination 5 to 16 years after cementation, the abutment teeth were clinically and radiographically evaluated. Besides the assessment of periodontal parameters and vitality testing, the presence of carious lesions of the abutment teeth, loss of retention, fracture of bridgework, and fracture of abutment teeth were also recorded. The Student's t test was used to detect differences between abutment teeth and control teeth with natural crowns as well as over time within the groups. RESULTS: Plaque scores and bleeding on probing were low at both abutment and nonabutment teeth. Mean probing pocket depth and level of the clinical attachment never exceeded 3.0 mm in both groups. The radiographic bone levels at abutments were stable within 3% over the observation period. Of the 120 initially vital abutment teeth, 12 (10%) lost vitality during the observation period; one (1%) of the 119 initially nonvital abutments showed periapical pathology. Development of secondary caries was observed at 8% of the 239 abutment teeth. In total, 8% of the abutment teeth were affected by loss of retention, which made up more than half of all technical problems. Material fractures only occurred occasionally, affecting from 1% to less than 3% of the abutment teeth. Fracture of abutment teeth amounted to 3% and was twice as frequent at abutments adjacent to cantilevers compared to abutments not adjacent to cantilevers. CONCLUSION: The most frequent biologic (caries) and technical complications (loss of retention) made up more than half of all problems recorded. These problems may be at least partially avoided by performing optimal plaque control and by strictly observing the rules for preparation of retentive FPD abutments.
Asunto(s)
Pilares Dentales , Diseño de Dentadura , Dentadura Parcial Fija , Arcada Parcialmente Edéntula/rehabilitación , Adulto , Anciano , Anciano de 80 o más Años , Pérdida de Hueso Alveolar/diagnóstico por imagen , Pérdida de Hueso Alveolar/etiología , Distribución de Chi-Cuadrado , Estudios Transversales , Caries Dental/etiología , Índice de Placa Dental , Fracaso de la Restauración Dental , Retención de Dentadura , Dentadura Parcial Fija/efectos adversos , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Índice Periodontal , Radiografía , Estudios Retrospectivos , Estadísticas no Paramétricas , Fracturas de los Dientes/etiología , Resultado del TratamientoRESUMEN
The aims of this study were to compare clinical and microbiological features in the peri-implant area of implants carrying either screw retained or cemented suprastructures, and to investigate the relationship between the peri-implant microflora, the microbiota on the inner surface of removable suprastructures, and the periodontal microflora within the same subject. In 15 partially edentulous patients with ITI implants used as abutments for crown and bridge reconstructions, microbial samples were taken i) from the deepest periodontal pocket of each quadrant, ii) from the sulcus of the implants and iii) from the internal surface of the screw retained suprastructures. The samples were cultured using continuous anaerobic techniques. Five patients were found with both screw retained (S) and cemented (C) suprastructures. In these subjects the mean total cultivable counts were significantly higher in peri-implant samples from group C than in samples from group S. Furthermore, peri-implant samples of group S yielded a higher proportion of coccoid cells in the darkfield microscope and demonstrated absence of large spirochetes. From the 15 patients, Porphyromas gingivalis was detected in 10% of the periodontal samples and in only one peri-implant sample. Prevotella intermedia was detected in 33% of the periodontal and in 30% of the peri-implant samples. Fusobacterium spp. had a prevalence of 58% in the periodontal samples and was recovered from 50% of the peri-implant samples. Actinobacillus actinomycetemcomitans was not detected in any dental or peri-implant sample. In 1 case, however, the organism was recovered from the internal surface of the suprastructure. Linear regression analysis showed a significant relationship between the frequency of micro-organisms in peri-implant samples of group S and in samples from the inner surface of the suprastructure. Furthermore, there was a significant correlation between the incidence of micro-organisms in dental samples and i) in peri-implant samples of group S and ii) in samples from the internal suprastructure surface. These findings indicate, that the microbial leakage through the gap between the suprastructure and the abutment plays an important role in the bacterial colonization of the internal part of screw retained crowns and bridges. The study furthermore confirms the impact of the dental microflora on the microbial colonization of implants. This factor appears to be more important than the mode of fixation of the suprastructure.
Asunto(s)
Bacterias Anaerobias/aislamiento & purificación , Implantes Dentales/microbiología , Diseño de Prótesis Dental , Retención de Prótesis Dentales , Periodoncio/microbiología , Adulto , Anciano , Cementación , Filtración Dental/microbiología , Placa Dental/microbiología , Índice de Placa Dental , Retención de Prótesis Dentales/instrumentación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Bolsa Periodontal/microbiología , Análisis de Regresión , Estadísticas no ParamétricasRESUMEN
In most of the studies on long-term radiographic evaluations of crestal bone levels adjacent to dental implants, no baseline radiographs taken immediately postsurgically had been obtained. The aim of this study was to test the reproducibility of a simple radiographic method for linear measurements of changes in bone levels and to evaluate changes in crestal bone levels adjacent to non-submerged ITI implants 1 year following the surgical procedure. From 128 patients enrolled in a clinical and radiographic longitudinal study 40 patients also had radiographs taken immediately postsurgically. They were, however, not obtained as "identical" images. The radiographs were mounted onto slides and projected on a screen. Mesially and distally from 57 implants triplicate linear measurements of the distance implant shoulder to bone crest were taken, using known dimensions of the implants as internal reference distances. The median difference of 213 (out of 228 possible) duplicate measurements was 0.00 mm (ranging from -1.72 mm to +1.47 mm when comparing the second to the third reading). Some 81% of the double measurements were within +/- 0.5 mm and the precision was 0.30 mm. In the immediate postoperative radiographs the median mesial bone level was located at 2.07 mm (distally 2.19 mm) from the implant shoulder. A statistically significant amount of bone loss in the first year was observed mesially (median = -0.78 mm) and distally (-0.85 mm) (Wilcoxon matched pairs signed rank test P < or = 0.001). No statistically significant influence of the implant location, the implant length, type of the implant (screw; cylinder) was observed (Kruskal-Wallis P > 0.05). The age of the patients was not correlated significantly to the amount of bone loss observed. In conclusion, methodological limitations existed when evaluating linear bone changes in non-identical radiographs using reference dimensions of the implants. The amount of postsurgical bone loss estimated in other studies was confirmed when using an immediate postoperative radiograph as a baseline.