Photogrammetry Impression Technique: A Case History Report.

PURPOSE: The aim of this report is to present photogrammetry as a reliable step in the fabrication of a full-arch immediate rehabilitation. MATERIALS AND METHODS: A 59-year-old man attended the department seeking dental rehabilitation for the sequelae of severe oral health neglect. The mandibular teeth suffered from advanced periodontal disease and the patient wore a maxillary complete denture. An irreversible hydrocolloid impression of the mandibular arch was made, poured in stone, and digitally scanned to create the first stereolithography (STL) file. All teeth with the exception of two retained as landmarks were extracted, and seven implants were placed under local anesthesia and their positions recorded using photogrammetry. Maxillary and mandibular dental arch alginate impressions were made, poured in laboratory stone, and scanned. A provisional restoration was placed 7 hours after surgery using the STL files to determine the best-fit line. RESULTS: Radiographic and clinical follow-up after 1 year showed a favorable evolution of the implants. No screw loosening or other mechanical or biologic complications were observed. CONCLUSION: The case history using the described system suggests certain advantages over conventional techniques. More research is needed to assess the possible benefits associated with photogrammetry when making implant-supported restorations.

Actualización sobre la optimización de la estética en prótesis fija mediante el manejo tisula / Update on the optimisation of aesthetics in fixed protheses through tissue handling

Las restauraciones localizadas en la zona estética orofacial son un reto especialmente difícil cuando existe pérdida acusada del reborde residual. En este trabajo se revisan distintas opciones de tratamiento para mejorar la apariencia de los tejidos blandos en los tratamientos con prótesis fija convencional. Para ello se han seleccionado artículos científicos nacionales e internacionales publicados en los últimos diez años. Para la introducción de conceptos no se establece límite de antigüedad. Básicamente, los hallazgos obtenidos de la revisión bibliográfica pueden sintetizarse en lo siguiente: una vez realizada una correcta selección del caso, distintos tipos de tratamiento demostraron aportar resultados satisfactorios para la estética de los tejidos blandos en el tratamiento con prótesis fija convencional. En primer lugar, se proponen tratamientos destinados a modificar la esté- tica manteniendo los tejidos duros y blandos (pónticos ovoides, tratamientos ortodóncicos, técnicas de preservación alveolar, regeneración tisular guiada, injerto monocortical). En segundo lugar, se indican tratamientos quirúrgicos de tejidos duros (osteoplastia/ostectomía) y blandos (injertos de tejido blando, gingivoplastia/gingivectomía, distintos tipos de colgajo). Como última indicación, los materiales de restauración actuales permiten alcanzar resultados estéticos aceptables. En la actualidad, tanto los tratamientos quirúrgicos como los protésicos son considerados estrategias valiosas para realizar un adecuado manejo tisular. El injerto de tejido conectivo es el procedimiento quirúrgico más predecible en el tratamiento de las recesiones, mientras que los pónticos constituyen el procedimiento protésico de elección para obtener una estética apropiada del margen gingival (AU)

Restorations in the aesthetic orofacial zone are particularly challenging in presence of intense resorption of the residual ridge. In this paper various treatment options are reviewed focusing on the improvement of the appearance of the soft tissues combined with conventional fixed prostheses. A deep and rigorous selection of national and international scientific papers published in the last ten years has been made. No age limit was set to describe the key concepts. Basically, the findings that emerge from the literature review can be summarized as follows: once made a correct selection of the case, different types of treatments have been shown to provide satisfactory aesthetic of the soft tissues in combination with conventional fixed prostheses. Treatments that intend to modify the aesthetics preserving hard and soft tissues are proposed (i.e., ovoid pontics, orthodontic treatment, alveolar preservation techniques, guided tissue regeneration, monocortical graft). In addition, surgical treatments including hard tissue (osteoplasty / ostectomy) and soft tissue modification (i.e., soft tissue grafts, gingivoplasty / gingivectomy, various types of flap, etc.) are detailed. Nowadays, both prosthetic and surgical treatments are considered valuable strategies for adequate tissue handling. The connective tissue graft may be considered as the most predictable surgical procedure in the management of recessions, whereas pontics are the first choice for achieving suitable aesthetic results in shaping the gingival margin (AU)

Vertical misfit of laser-sintered and vacuum-cast implant-supported crown copings luted with definitive and temporary luting agents

Objectives. This study aimed to evaluate the vertical discrepancy of implant-supported crown structures constructed with vacuum-casting and Direct Metal Laser Sintering (DMLS) technologies, and luted with different cement types. Study Design. Crown copings were fabricated using: (1) direct metal laser sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC); and (3) vacuum-cast Ti (CT). Frameworks were luted onto machined implant abutments under constant seating pressure. Each alloy group was randomly divided into 5 subgroups (n = 10 each) according to the cement system utilized: Subgroup 1 (KC) used resin-modified glass-ionomer Ketac Cem Plus; Subgroup 2 (PF) used Panavia F 2.0 dual-cure resin cement; Subgroup 3 (RXU) used RelyX Unicem 2 Automix self-adhesive dual-cure resin cement; Subgroup 4 (PIC) used acrylic/urethane-based temporary Premier Implant Cement; and Subgroup 5 (DT) used acrylic/urethane-based temporary DentoTemp cement. Vertical misfit was measured by scanning electron microscopy (SEM). Two-way ANOVA and Student-Newman-Keuls tests were run to investigate the effect of (..) (AU)

Vertical misfit of laser-sintered and vacuum-cast implant-supported crown copings luted with definitive and temporary luting agents.

OBJECTIVES: This study aimed to evaluate the vertical discrepancy of implant-supported crown structures constructed with vacuum-casting and Direct Metal Laser Sintering (DMLS) technologies, and luted with different cement types. STUDY DESIGN: Crown copings were fabricated using: (1) direct metal laser sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC); and (3) vacuum-cast Ti (CT). Frameworks were luted onto machined implant abutments under constant seating pressure. Each alloy group was randomly divided into 5 subgroups (n = 10 each) according to the cement system utilized: Subgroup 1 (KC) used resin-modified glass-ionomer Ketac Cem Plus; Subgroup 2 (PF) used Panavia F 2.0 dual-cure resin cement; Subgroup 3 (RXU) used RelyX Unicem 2 Automix self-adhesive dual-cure resin cement; Subgroup 4 (PIC) used acrylic/urethane-based temporary Premier Implant Cement; and Subgroup 5 (DT) used acrylic/urethane-based temporary DentoTemp cement. Vertical misfit was measured by scanning electron microscopy (SEM). Two-way ANOVA and Student-Newman-Keuls tests were run to investigate the effect of alloy/fabrication technique, and cement type on vertical misfit. The statistical significance was set at α = 0.05. RESULTS: The alloy/manufacturing technique and the luting cement affected the vertical discrepancy (p < 0.001). For each cement type, LS samples exhibited the best fit (p < 0.01) whereas CC and CT frames were statistically similar. Within each alloy group, PF and RXU provided comparably greater discrepancies than KC, PIC, and DT, which showed no differences. CONCLUSIONS: Laser sintering may be an alternative to vacuum-casting of base metals to obtain passive-fitting implant-supported crown copings. The best marginal adaptation corresponded to laser sintered structures luted with glass-ionomer KC, or temporary PIC or DT cements. The highest discrepancies were recorded for Co-Cr and Ti cast frameworks bonded with PF or RXU resinous agents. All groups were within the clinically acceptable misfit range.

Vertical discrepancy and microleakage of laser-sintered and vacuum-cast implant-supported structures luted with different cement types.

OBJECTIVES: This study aimed to evaluate the vertical misfit and microleakage of laser-sintered and vacuum-cast cement-retained implant-supported frameworks. METHODS: Three-unit implant-fixed structures were constructed with: (1) laser-sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC); and (3) vacuum-cast Pd-Au (CP). Every framework was luted onto 2 prefabricated abutments under constant seating pressure. Each alloy group was randomly divided into three subgroups (n=10) according to the cement used: (1) Ketac Cem Plus (KC); (2) Panavia F 2.0 (PF); and (3) RelyX Unicem 2 Automix (RXU). After 30 days of water ageing, vertical discrepancy was measured by SEM, and marginal microleakage was scored using a digital microscope. Three-way ANOVA and Student-Newman-Keuls tests were run to investigate the effect of alloy/fabrication technique, FDP retainer, and cement type on vertical misfit. Data for marginal microleakage were analysed with Kruskal-Wallis and Dunn's tests (α=0.05). RESULTS: Vertical discrepancy was affected by alloy/manufacturing technique and cement type (p<0.001). Despite the luting agent, LS structures showed the best marginal adaptation, followed by CP, and CC. Within each alloy group, KC provided the best fit, whilst the use of PF or RXU resulted in no significant differences. Regardless of the framework alloy, KC exhibited the highest microleakage scores, whilst PF and RXU showed values that were comparable to each other. CONCLUSIONS: Laser-sintered Co-Cr structures achieved the best fit in the study. Notwithstanding the framework alloy, resin-modified glass-ionomer demonstrated better marginal fit but greater microleakage than did MDP-based and self-adhesive dual-cure resin cements. All groups were within the clinically acceptable misfit range. CLINICAL SIGNIFICANCE: Laser-sintered Co-Cr may be an alternative to cast base metal and noble alloys to obtain passive-fitting structures. Despite showing higher discrepancies, resin cements displayed lower microleakage than resin-modified glass-ionomer. Further research is necessary to determine whether low microleakage scores may guarantee a suitable seal that could compensate for misfit.

Evaluation of fit of cement-retained implant-supported 3-unit structures fabricated with direct metal laser sintering and vacuum casting techniques.

This study evaluated the vertical discrepancy of implant-fixed 3-unit structures. Frameworks were constructed with laser-sintered Co-Cr, and vacuum-cast Co-Cr, Ni-Cr-Ti, and Pd-Au. Samples of each alloy group were randomly luted in standard fashion using resin-modified glass-ionomer, self-adhesive, and acrylic/urethane-based cements (n = 12 each). Discrepancies were SEM analyzed. Three-way ANOVA and Student-Newman-Keuls tests were run (P < 0.05). Laser-sintered structures achieved the best fit per cement tested. Within each alloy group, resin-modified glass-ionomer and acrylic/urethane-based cements produced comparably lower discrepancies than the self-adhesive agent. The abutment position did not yield significant differences. All misfit values could be considered clinically acceptable.

Evaluation of fit of zirconia posterior bridge structures constructed with different scanning methods and preparation angles.

This study evaluated the influence of scanning method, abutment position, and preparation angle on the vertical seal of three-unit posterior zirconia structures. Sixty differently angled metallic models were machined to receive 30 bridge frameworks. For each preparation type, half of the structures were waxed-up and digitized, whereas the other half were computer-designed after the abutments were scanned. Once milled, the samples were cemented in standard fashion. Misfit was assessed by scanning electron microscopy. Three-way analysis of variance showed significant differences. Computer-designed structures achieved the highest accuracy (P < 0.0001). No significant differences were recorded concerning the abutment position and convergence angle. All discrepancy values were within the clinically acceptable range.

Influence of CAD/CAM scanning method and tooth-preparation design on the vertical misfit of zirconia crown copings.

PURPOSE: To evaluate the influence of scanning method, finish line type and occlusal convergence angle of the teeth preparations on the vertical misfit of zirconia crown copings. METHODS: 20 standardized stainless-steel master dies were machined simulating full-crown preparations. The total convergence angle was 15 degrees or 20 degrees (n=10 each). Two of the finish line types: a chamfer (CH) and a shoulder (SH) were prepared around the contour of each abutment. Over these dies, 20 structures were made by CAD/CAM (Cercon, Dentsply). An optical laser digitized the wax patterns of 10 single-unit copings (WS), and 10 abutments were direct-scanned to design the cores by computer (DS). Zirconia milled caps were luted onto the models under constant seating pressure. Vertical discrepancy was assessed by SEM. Misfit data were analyzed using ANOVA and Student-Newman-Keuls (SNK) test for multiple comparisons at alpha = 0.05. RESULTS: Vertical gap measurements of WS copings were significantly higher than those of DS frames (P < 0.0001). SH exhibited statistically higher discrepancies than CH when combined with a 15-degree occlusal convergence angle regardless of the scanning method (P < 0.05). The taper angle of the preparation (15 degrees vs. 20 degrees) had no effect on the marginal adaptation of chamfered samples.

Influence of CAM vs. CAD/CAM scanning methods and finish line of tooth preparation in the vertical misfit of zirconia bridge structures.

PURPOSE: To evaluate the influence of CAD/CAM scanning method (wax-up digitization vs. direct scanning of tooth preparation) and finish line type (chamfer vs. shoulder) on the vertical fit of zirconia frameworks for three-unit posterior-lower bridges. METHODS: 30 sets of two stainless steel master dies were prepared with different marginal designs (chamfer and shoulder) around the contour of each abutment. Over these samples, 30 structures for three-unit posterior-lower bridges were made with Cercon Smart Ceramics CAD/CAM system (Dentsply). An optical laser digitized the wax patterns of 15 bridge structures, and 15 pairs of master dies were directly scanned for designing by computer the remaining half of frames. All zirconia milled structures were luted onto the metallic models with a special clamp made-up to maintain constant seating pressure. Vertical discrepancy around the margins was assessed under scanning electron microscopy (SEM). Misfit data was analyzed using two-way ANOVA and Tukey's test for multiple comparisons at a = 0.05. RESULTS: Vertical discrepancy of the wax-up/digitized bridge structures was significantly higher than that of the computer-designed frameworks (P < 0.0001). No statistically significant differences were found between the chamfer and shoulder vertical misfit values assessed around the metallic models margins (P = 0.55).

Evaluación de 80 implantes, sometidos a carga inmediata en desdentados inferiores tras un seguimiento de dos años / Evaluation of 80 implants subjected to immediate loading in edentulous mandibles after two years of follow-up

Objetivo: Analizar el comportamiento tanto clínico como radiológico de ochentas implantes con una nueva superficie tratada mediante una disolución de ácido sulfúrico y fluorhídrico con posterior tratamiento térmico, que han sido sometidos a carga inmediata en pacientes rehabilitados con sobredentaduras inferiores. Diseño del artículo: Estudio observacional, prospectivo en 20 pacientes rehabilitados con sobredentaduras inferiores, soportadas sobre cuatro implantes de 13 milímetros de longitud. Todos los pacientes fueron planificados e incluídos tras el consentimiento, anamnesis, exploración clínica y estudio radiográfico y mediante montaje clínico previo de la prótesis inferior. Resultados: Durante los dos años de seguimiento, se ha obervado que el acúmulo de placa y cálculo no ha sido importante, oscilando los índices (Silness y Löe) entre 0 y 1. El sondaje periodontal, ha sido favorable no encontrando pacientes que superasen 2 milímetros. Los controles radiográficos mostraron a lo largo del seguimiento ausencia de fracaso implantológico. Las pérdidas óseas cervicales, durante el primer año, no existieron en un alto porcentaje (65%), mientras que en un 10% se produjo la reabsorción de la mitad cervical y en el 35% restante sobre las ¾ partes cervicales. El comportamiento durante el segundo año fue compatible a los patrones estándares, observándose pérdidas que oscilaron entre 0,5 y 1,5 milímetros. Conclusiones: La rehabilitación mediante sobredentaduras inferiores, debiera contemplarse como una indicación prioritaria, planteándose la sustitución de los tratamientos implantológicos con períodos de reposo convencionales y/o precoces

Aim: An analysis is made of the clinical and radiological behavior of 80 implants with a new surface subjected to etching with a sulfuric and hydrofluoric acid solution followed by thermal treatment, and subjected to immediate loading in patients with lower overdentures. Study design: A prospective observational study was made of 20 patients with lower overdentures supported by four implants measuring 13 mm in length. All patients were included after the obtainment of informed consent, anamnesis, clinical examination and radiological study, with prior clinical elaboration of the lower dentures. Results: Over two years of follow-up, no important plaque or tartar accumulation was observed (with Silness and Löe indexes of 0-1). Periodontal probing proved favorable, with no pocket depths of over 2 mm in any case. The radiological controls showed no implant failures during follow-up. No cervical bone loss was recorded in the first year in a large proportion of cases (65%), while reabsorption of the cervical half was observed in 10%, and of three-quarters of the cervical portion in the remaining 35%. Performance in the second year was compatible with the standard references – with losses of between 0.5-1.5 mm. Conclusions: Rehabilitation with lower overdentures should be regarded as a priority indication, and implantological treatment substitution by conventional and/or early resting periods should be considered

Evaluation of 80 implants subjected to immediate loading in edentulous mandibles after two years of follow-up.

AIM: An analysis is made of the clinical and radiological behavior of 80 implants with a new surface subjected to etching with a sulfuric and hydrofluoric acid solution followed by thermal treatment, and subjected to immediate loading in patients with lower overdentures. STUDY DESIGN: A prospective observational study was made of 20 patients with lower overdentures supported by four implants measuring 13 mm in length. All patients were included after the obtainment of informed consent, anamnesis, clinical examination and radiological study, with prior clinical elaboration of the lower dentures. RESULTS: Over two years of follow-up, no important plaque or tartar accumulation was observed (with Silness and Loe indexes of 0-1). Periodontal probing proved favorable, with no pocket depths of over 2 mm in any case. The radiological controls showed no implant failures during follow-up. No cervical bone loss was recorded in the first year in a large proportion of cases (65%), while reabsorption of the cervical half was observed in 10%, and of three-quarters of the cervical portion in the remaining 35%. Performance in the second year was compatible with the standard references--with losses of between 0.5-1.5 mm. CONCLUSIONS: Rehabilitation with lower overdentures should be regarded as a priority indication, and implantological treatment substitution by conventional and/or early resting periods should be considered.