Minimizing excess cement around implant restorations: an in vitro study of cementation techniques.

Excess cement around cement-retained implant crowns is associated with a higher incidence of peri-implantitis, but there are limited data to indicate which cement application technique minimizes excess cement. The purpose of this in vitro study was to evaluate the amount of excess cement that resulted from different cement application techniques. Fifty identical titanium custom abutments and monolithic zirconia crowns were digitally designed and milled in the shape of a maxillary first molar. Ten crowns were cemented by applying temporary cement only to the intaglio coronal surface of the crown; these specimens were used as a control group to determine the amount of cement to be used in all other groups. Four different cement application methods were evaluated (n = 10): wall layer technique, in which cement was brushed on the intaglio axial walls of the crown; precementation technique, in which cement was applied to the intaglio coronal aspect of the crown, and the crown was precemented on an abutment replica, quickly removed, and then repositioned on the milled abutment; rim application, in which cement was applied to the cervical marginal rim of the crown; and increased cement space, in which the cement space was increased to 60 µm (compared with 40 µm in other groups) and cement was brushed on the intaglio coronal surface. Digital photographs of the cemented crowns were taken, and image editing software was used to measure the displacement of excess cement, that is, the distance that it traveled below the finish line on the mesial, distal, buccal, and lingual surfaces. Excess cement was then removed from each specimen and weighed. An analysis of variance test was used to evaluate the difference among groups, and each pair of groups was compared with the t test. Compared with all of the other experimental groups, specimens cemented with the wall layer technique showed a significantly smaller amount of cement excess in terms of both the distance traveled and weight (P < 0.05). Based on the findings, the wall layer cementation technique, in which cement is brushed on the intaglio walls of the crown, is recommended to reduce excess cement around implant crowns.

Does the calcar femorale affect the position of uncemented short stems?

BACKGROUND AND PURPOSE: Metaphyseal-stabilised short stems rely on sufficient metaphyseal fixation and are inserted by following the medial cortex. This type of stem is used extensively in our institution, and we observed on occasion unintended implant positioning with an increased distance between the implant and the medial cortex. A bony structure within the proximal femur which was first described in 1874 and named the calcar femorale, coincides with this phenomenon.The aim of this study was to investigate the impact of the calcar femorale on the position of a metaphyseal-stabilised short stem. PATIENTS AND METHODS: The frequency of cases with an increased distance between medial cortex and the implanted short stem was analysed in 52 consecutive patients. Additionally, we performed an anatomical CT study with 60 cadaveric femora to obtain more detailed information on the anatomy of the calcar femorale. Detailed measurements regarding the calcar femorale and its relationship to the proximal femur were obtained. From this, we derived implications for the implantation of a short stem prosthesis. RESULTS: In 50% of all cases, we found an increased gap between the stem and the medial cortex. An increased gap did not significantly affect stem size, position, or subsidence rate, but in cases with an increased gap we found fewer stems with a radiologically optimum fit. The calcar could be identified in all 60 cadavers. The calcar femorale angle showed a high correlation with the mechanical antetorsion (0.87, p = 0.02) and the functional antetorsion (0.86, p = 0.05) of the femur. CONCLUSIONS: The calcar femorale is a consistent anatomical structure which may be the cause for an increased gap medial to the short stem in 50% of our cases. It limits the intramedullary space and influences both stem size and orientation. The CF angle which correlates with femoral antetorsion may influence the anteversion of the stem.

Effect of cementation protocols on the fracture load of bilayer ceramic crowns manufactured by the Rapid Layer Technology.

To evaluate the fracture load of bilayer ceramic crowns manufactured by Rapid Layer Technology (RLT) after different cementation protocols of the veneering ceramic to the zirconia infrastructures. Sixty epoxy resin preparations simulating a molar tooth were obtained and 60 zirconia infrastructures and feldspathic crowns were manufactured by RLT and divided into 6 groups according to the cementation protocol at the interface to veneering ceramic (n=10): Ctr- control: conventional resin cement; Al- Al2O3 sandblasting 50µm + conventional resin cement; Al/MDP- Al2O3 sandblasting (50µm) + resin cement with MDP; Sil- silicatization 30µm + conventional resin cement; Gl/HF- glaze + hydrofluoridric acid (5%,60s) + silane + conventional resin cement; Gl- glazing as bonding agent. The feldspathic ceramic internal surface was etched with fluoridric acid (5%) + silane followed by cementation according to respective protocols. All samples were mechanically cycled (200N and 4.5x105 Pa, 37°C, 2x106 cycles, 3.4Hz) and submitted to axial compressing fracture load test (10kN, 0.5mm/min). The results(N) were submitted to descriptive and analytical statistical analysis with 1-way ANOVA, Weibull, and the Tukey test (α=0.05). ANOVA revealed that there was a significant difference among the tested groups (p<0.0001). The group Al/MDP presented the higher resistance to fracture (1972.46A N), followed by the Ctr group (1584.41B N). The characteristic strength(σ0) was significantly different (p=0.000). The crack and chipping were the predominant failures. The air-abrasion at the external surface of zirconia with Al2O3 followed by cementation with MDP resin cement, should be selected to Rapid Layer Technique when felspathic ceramic is used as veneer ceramic.

Effect of cemented vs uncemented on outcomes for hemiarthroplasty in the elderly: A meta-analysis of randomized clinical trials.

PURPOSE: In patients undergoing hemiarthroplasty in the elderly, the choice of the cemented method remains controversial. This meta-analysis was undertaken to compare the impact of cemented vs uncemented on outcomes for hemiarthroplasty in the elderly. METHODS: This study included randomized controlled trials comparing the postoperative effects of cemented vs uncemented in patients with hemiarthroplasty. With no language restrictions, we searched Medline (Ovid), Embase (Ovid), Cochrane Central Register of Controlled Trials (Cochrane Collaboration), Clinical Trials.gov, the ISRCTN registry, as well as gray literature with no language restrictions from January 1966 to April 2023. Data were quantitatively summarized using a random-effects model. The primary outcome was 1-year mortality. RESULTS: This study included 13 randomized controlled trials with 3485 patients. The primary outcomes of the meta-analysis showed that cemented fixation in elderly patients undergoing hemiarthroplasty was superior to noncemented in 1-year mortality (risk ratio [RR] = 0.87, 95% confidence interval [CI]: 0.77, 0.97). Moreover, cemented was associated with a reduced risk of intraoperative periprosthetic fracture (RR = 0.19, 95% CI: 0.07, 0.50), postoperative periprosthetic fracture (RR = 0.34, 95% CI: 0.16,0.72), and loosening (RR = 0.33, 95% CI: 0.11, 0.97). CONCLUSIONS: Cemented hemiarthroplasty is superior to noncemented in terms of survival. Moreover, cementation reduces the incidence of some implant-related complications. More extensive trials are needed to provide adequate guidance for choosing the proper cemented method.

In vitro assessment of cementation of CAD/CAM fabricated prostheses over titanium bases. A systematic review.

OBJECTIVES: The objective of this study is to investigate the outcomes of clinically relevant laboratory studies regarding the cementation of implant-supported restorations over ti-bases. MATERIALS AND METHODS: The present study has been conducted according to PRISMA statement. An electronic search was performed, including publications up to March 2024, to identify studies investigating the parameters affecting the cementation between ti-bases and CAD/CAM prostheses. An assessment of the internal validity was performed, using a custom-made risk of bias tool (QUIN). RESULTS: From the included studies, 40.1% were reported on luting systems, 25% on ti-base surface treatment, 25% on restoration surface, 21.8% on restoration material, and 18.7% on ti-base height. The majority of the included studies were associated with a medium risk of bias. In the absence of micro-retentive features, air-abrasion of ti-bases with a minimum height of 3.5 mm can be beneficial for restoration's retention. The bonding performance can vary not only between different bonding systems but also for different applications within the same system, based on a restoration's material and surface treatment as well as on ti-base height and surface treatment. CONCLUSIONS: The height of the ti-base seems to be the prevailing factor as it constitutes the prerequisite for other modifications of the bonding surfaces to have an advantageous effect. Since the parameters that can affect bonding performance between ti-base and restoration can interact with each other, it is important for the clinician to focus on verified bonding protocols.

The effect of ascorbic acid, QMix and other conditioning solutions on the bond strength of adhesively luted glass fiber-reinforced composite posts to root dentin, a laboratory study.

PURPOSE: This study was designed to investigate the effect of post space conditioning with different solutions on the bond strength of glass FRC posts and evaluate the mode of resin failure. METHODS: Sixty extracted human single rooted teeth were root filled using a resin sealer and suitable gutta-percha cones. Post spaces were prepared, and the teeth randomly allocated into 5 groups according to their irrigation regimens which included the following solutions: 17 % EDTA, 2 % CHX, 3 % NaOCl, 10 % ascorbic acid and QMix solutions. Post spaces were irrigated with 5 ml of the solution for 15 s and subsequently washed with distilled water and dried with paper points. Glass FRC posts were cemented into their spaces using a self-adhesive resin cement. The specimens were mounted in plexiglass molds using autopolymerizing acrylic resin. A universal testing machine was used to measure post retention at a crosshead speed of 2 mm/min. The results were analyzed by one-way ANOVA followed by Tukey HSD test (α = 0.05). Dislodged posts and post spaces were examined microscopically to evaluate retention failure. RESULTS: The Ascorbic acid group exhibited the highest mean retentive strength value at 229 N, followed by QMix at 198 N, NaOCl at 186 N, CHX at 170 N, and EDTA at 124 N. The mean value of the ascorbic acid group was significantly higher than EDTA group, p = 0.012. The failure category was primarily mixed. CONCLUSIONS: Rinsing post spaces with ascorbic acid exhibited significantly superior bond strength. The failure mode was mixed. CLINICAL SIGNIFICANCE: Irrigating post spaces with ascorbic acid solution before luting FRC posts significantly improves their bond strength compared to irrigation with EDTA solution. Irrigation with QMix solution produced the second highest retentive strength but showed no statistical significance when compared to using ascorbic acid, NaOCl, CHX, or EDTA solutions.

Influence of provisional cementation on the stability of adhesively bonded resin-based composite crowns.

PURPOSE: To investigate the influence of temporary cementation and subsequent bonding on the durability during in-vitro aging-simulation and fracture force of resin-based composite crowns. METHODS: Identical molar crowns (n=48, n=8 per group) were milled from resin-based composites and temporarily cemented and finally bonded to human molars. To simulate temporary application, crowns were cemented either with zinc-oxide-eugenol-cement (Tempbond) or with eugenol free zinc-oxide-cement (Tempbond NE). For a first simulation of a long-term provisional clinical application, thermal cycling, and mechanical loading (TCML 2 x 600 x 5°C-55°C, 2 minutes each cycle, distilled water, 240,000 cycles at 50N) was performed. After TCML all crowns were removed, cleaned, and luted either by using etch-and-rinse technique (Vococid, Futurabond U, Bifix QM) or a self-adhesive (Bifix SE) cementation system. A second thermal cycling and mechanical loading (TCML 2 x3,000 x 5°C/55°C, 2 minutes each cycle, distilled water, 1.2 x 106 at 50N) was accomplished to simulate 5 years of clinical application. To assess the survival of the crowns, the failure rates during TCML were documented. As controls, crowns were included without prior provisional cementation. After TCML all crowns were loaded to failure. Failure was categorized as fracture of the crown and partial loosening of the crown. RESULTS: All crowns survived both TCML procedures without any failures. The fracture values after TCML varied between 3,538.0 ± 1,041.2 N and 4,612.0 ± 801.5 N without significant (P= 0.146) differences between the individual groups. No correlation was found between fracture force and type of provisional cementation (zinc-oxide-eugenol vs. zinc-oxide: Pearson: -0.063/P= 0.672) or type of bonding (adhesive vs. self-adhesive: Pearson: -0.151/ P= 0.307). No different failure pattern was observed between the tested systems. CLINICAL SIGNIFICANCE: Regardless of the type of temporary cementation, there was no effect on the in-vitro performance or strength of the final permanently bonded crowns. Resin-based crowns might be bonded with adhesive or self-adhesive systems even after previous temporary cementation.

Restauração em resina composta semidireta em dente posterior: relato de caso / Semi-direct composite restoration in posterior toth: a case report

A escolha da técnica restauradora desempenha papel fundamental na eficácia e duração de um tratamento reabilitador. O objetivo deste relato de caso foi descrever a utilização da técnica semidireta para a confecção de uma restauração em resina composta em um primeiro molar inferior. A paciente apresentava uma restauração insatisfatória no dente 36, que necessitava ser substituída devido à infiltração por cárie. Optou-se pela técnica semidireta devido à amplitude da cavidade, que envolvia estruturas de suporte, e pela combinação das vantagens das abordagens direta e indireta. O procedimento envolveu a remoção de tecido cariado, a aplicação de hidróxido de cálcio pasta, seguida da aplicação de uma fina camada de ionômero de vidro e, posteriormente, resina fluída para realizar o selamento dentinário. O preparo foi realizado seguindo os princípios necessários. O elemento em questão foi moldado com silicone de adição e o arco antagonista, com alginato. Ambos modelos foram vertidos com silicone para modelos semirrígidos e montados em oclusor de peças de brinquedo. A restauração semidireta foi confeccionada em resina composta Filtek Z350 XT, respeitando a anatomia do dente 36. Pigmentos foram utilizados para aprimorar detalhes estéticos. Após acabamento e polimento, a peça foi condicionada e cimentada com cimento dual Relyx Ultimate. Pode-se concluir que a abordagem restauradora por meio da técnica semidireta construída em modelo semirrígido é uma opção terapêutica conservadora e vantajosa para dentes com extensa destruição coronária. Essa técnica possibilita a restauração de forma eficaz, garantindo tanto a estética quanto a função adequada do dente afetado(AU)

The choice of restorative technique plays a fundamental role in the effectiveness and duration of rehabilitation treatment. The objective of this case report was to describe the use of the semi-direct technique to create a composite resin restoration in a lower first molar. The patient had an unsatisfactory restoration on tooth 36, which needed to be replaced due to cavity infiltration. The semi-direct technique was chosen due to the amplitude of the cavity, which involved support structures, and the combination of advantages of the direct and indirect approaches. The procedure involved the removal of carious tissue, and the application of calcium hydroxide paste, followed by the application of a thin layer of glass ionomer and, subsequently, fluid resin to seal the dentin. The preparation was carried out following the necessary principles. The element in question was molded with addition silicone and the antagonist arch was molded with alginate. Both models were poured with silicone for semi-rigid models and mounted on toy parts occluders. The semi-direct restoration was made in Filtek Z350 XT composite resin, respecting the anatomy of tooth 36. Pigments were used to improve aesthetic details. After finishing and polishing, the piece was conditioned and cemented with Relyx Ultimate dual cement. It can be concluded that the restorative approach using the semi-direct technique built on a semi-rigid model is a conservative and advantageous therapeutic option for teeth with extensive coronal destruction. This technique allows for effective restoration, ensuring both the aesthetics and adequate function of the affected tooth(AU)

Long-term retention and survival of cemented implant-supported zirconia and metal-ceramic single crowns: A retrospective study.

OBJECTIVES: To evaluate the effect of different cement types on the incidence of failure and loss of retention of zirconia and metal-ceramic single crowns (SCs) cemented on implant abutments. METHODS: We placed 567 implant-supported SCs in 358 patients and retrospectively evaluated long-term retention for up to 12.8 years. The frameworks were made from metal alloy (n = 307) or zirconia (n = 260). SCs were cemented with permanent (glass-ionomer cement; n = 376) or semipermanent cement (zinc oxide non-eugenol cement; n = 191) on standardized (n = 446) or customized (n = 121) abutments. Kaplan-Meier curves were used to calculate the incidence of decementation. Differences between survival curves were assessed with log-rank tests. Cox-regression analysis was performed to evaluate multiple risk factors. RESULTS: Of the 567 SCs, 22 failed because of technical complications and four because of implant loss. Loss of retention was observed in 50 SCs. Analysis revealed a 7% probability of loss of retention for zirconia and 16% for metal-ceramic SCs after 10 years (p = .011). After 5 years, loss of retention was higher for standardized abutments than for customized abutments (p = .014). The probability of loss of retention was higher with semipermanent than with permanent cement (p = .001). Cox-regression analysis revealed semipermanent cement as the only significant risk factor for SC failure (p = .026). CONCLUSIONS: In contrast to semipermanent cement, permanent cement provides acceptable long-term retention of cemented implant-supported SCs. These possible positive effects of customized abutments have to be controlled with larger sample sizes.

Total knee arthroplasty using a cemented single-radius, condylar-stabilized design performed without posterior cruciate ligament sacrifice.

Aims: Total knee arthroplasty (TKA) with a highly congruent condylar-stabilized (CS) articulation may be advantageous due to increased stability versus cruciate-retaining (CR) designs, while mitigating the limitations of a posterior-stabilized construct. The aim was to assess ten-year implant survival and functional outcomes of a cemented single-radius TKA with a CS insert, performed without posterior cruciate ligament sacrifice. Methods: This retrospective cohort study included consecutive patients undergoing TKA at a specialist centre in the UK between November 2010 and December 2012. Data were collected using a bespoke electronic database and cross-referenced with national arthroplasty audit data, with variables including: preoperative characteristics, intraoperative factors, complications, and mortality status. Patient-reported outcome measures (PROMs) were collected by a specialist research team at ten years post-surgery. There were 536 TKAs, of which 308/536 (57.5%) were in female patients. The mean age was 69.0 years (95% CI 45.0 to 88.0), the mean BMI was 32.2 kg/m2 (95% CI 18.9 to 50.2), and 387/536 (72.2%) survived to ten years. There were four revisions (0.7%): two deep infections (requiring debridement and implant retention), one aseptic loosening, and one haemosiderosis. Results: Kaplan-Meier analysis demonstrated no difference in implant survival according to sex, age, or obesity status. Ten-year PROMs were available for 196/387 (50.6%) surviving patients and were excellent: mean Oxford Knee Score 34.4 (95% CI 32.7 to 36.1); mean Forgotten Joint Score (FJS) 51.2 (95% CI 16.1 to 86.3); mean EuroQol five-dimension five-level questionnaire score 69.9 (95% CI 46.8 to 93.0); 141/196 (71.9%) achieved the 22-point FJS patient-acceptable symptom state (PASS); and 156/196 (79.6%) were "very satisfied or satisfied". Conclusion: This is the only large study reporting ten-year implant survival and functional outcomes of TKA using a cemented single-radius design and with a CS tibial bearing construct. The findings of excellent implant survival, safety, and functional outcomes indicate that this combination is a safe and effective option in routine TKA. Further investigation of this single-radius design TKA with CS tibial bearings with well-matched patient study groups will allow further insight into the performance of these implants.

Biological interaction, esthetics, handling, and loss rate of temporary luting cements - a clinical single-blind randomized controlled trial.

OBJECTIVES: To evaluate three temporary luting cements in terms of their restoration loss rates, biological interactions, esthetic properties, and handling characteristics. MATERIALS AND METHODS: 75 adults requiring fixed prosthodontics voluntarily participated in a single-blind, randomized controlled trial. After preparation, temporary restorations were luted with a randomly selected temporary luting cement (either Provicol QM Plus (PQP), Bifix Temp (BT), or Provicol QM Aesthetic (PQA)). Clinical examinations were performed one to two weeks after cementation. The following criteria were evaluated: tooth vitality, percussion, hypersensitivity, gingival bleeding, odor formation, esthetics, cement handling, removability, cleanability, and retention loss. Antagonistic teeth served as controls. Statistical analysis was performed using the paired t-test, one-way ANOVA, Pearson's chi-square and Fisher's exact test, where appropriate. RESULTS: The overall loss rate of temporary restorations was 16.0%, showing no cement-specific differences. Postoperative hypersensitivity occurred in 8% of cases regardless of cement type. Esthetic impairment was reported by 31% of the PQP-fixed restorations, compared with 4.0% and 4.2% of the BT and PQA-bonded restorations. Cement application was reported to be easy in 100% of cases, excess removal in 88-96%, depending on the cement used. CONCLUSIONS: The choice of luting material affects the esthetic appearance of a temporary restoration and should be considered, particularly in restorations in esthetically demanding areas. No significant differences between the cements were identified regarding biocompatibility, handling, and loss rate. CLINICAL RELEVANCE: Translucent cements can help to reduce color interferences, resulting in a more appealing appearance of the temporary restoration.

The influence of finishing line and luting material selection on the seating accuracy of CAD/CAM indirect composite restorations.

OBJECTIVES: This study aimed to assess the seating accuracy of resin composite CAD/CAM overlay restorations, employing various preparation designs and luting materials (pre-heated composite (HC) or resin cement (RC)). METHODS: A human molar's STL file was utilized to create 100 3D-printed resin tooth replicas, randomly distributed into 5 groups (n = 20) based on finishing line preparation designs: 1) Rounded shoulder above the dental equator - DE (SA); 2) Chamfer above the DE (CA); 3) Butt joint above the DE (BJ); 4) Rounded shoulder below the DE (SB); 5) Chamfer below the DE (CB). Digital impressions were acquired for all replicas, and restorations milled using Tetric CAD (Ivoclar Vivadent). The restorations were luted with HC (Tetric Prime, Ivoclar Vivadent) or RC (RelyX Universal, 3 M). Seating accuracy was evaluated through digital scans during try-in without any luting agent and post-cementation using a 3D analysis software (Geomagic wrap, 3D Systems). Data were statistically analyzed using Two-Way ANOVA (p < 0.05). RESULTS: The type of luting material (RC vs HC), preparation design, and their interactions significantly impacted 3D seating of the restorations (p < 0.001). HC exhibited higer volumetric increase than RC. BJ and CA designs consistently demonstrated superior seating accuracy, irrespective of the luting material used. CONCLUSIONS: The utilization of pre-heated composite resin could negatively influence the seating of overlay restorations, probably due to its higher viscosity when compared to the resin cement. However, when HC is selected as luting agent, preparation designs lacking internal angles are recommended for enhancing the precision of overlays seating.

Periprosthetic Fractures: A Rising Tide of Hip Arthroplasty Failure Noted in the American Joint Replacement Registry and the Preventative Role of Cemented Stems.

BACKGROUND: This investigation examined cemented femoral component use in total hip arthroplasty (THA) and its impact on the incidence of periprosthetic fractures (PPFx), a common failure mode in THA. The study leverages data from the American Joint Replacement Registry (AJRR) to assess trends in cemented femoral component usage over time, its association with PPFx rates, and compares the survivorship and 90-day complication rates between cemented and cementless femoral component THAs. METHODS: Primary THAs, captured in the AJRR, in patients aged 65 years and older from 2012 to 2021 were analyzed. Variables considered included age, sex, race, region, teaching status, year, Charlson comorbidity index, and institution bed size. Analysis compared fixation types for THA on all-cause linked revision and PPFx. Logistic regression models analyzed the odds ratios for all-cause linked revision and PPFx for any follow-up time as well as for 90-day revision. The models were adjusted for the listed variables. RESULTS: During the study period, the rate of cement utilization as a percentage of primary THAs performed and reported to the AJRR increased from 4.4 to 8.3%. The rate of THA failure from PPFx increased from 11.4 to 33.3%. When both fixation groups were compared in the univariate analysis, there was a statistically significant difference in all demographic variables (P < .001). To account for this, multivariable logistic regression models were applied. In our models, cemented stems showed a 54.4% (odds ratio: 0.456; 95% confidence interval: 0.347 to 0.599; P < .0001) and 65.8% (odds ratio: 0.342; 95% confidence interval: 0.237 to 0.493; P < .0001) lower risk of PPFx linked and PPFx early linked revision, respectively. CONCLUSIONS: Periprosthetic fractures are becoming a leading failure mode for THAs in the AJRR. Given cemented fixation's relative resistance to this failure mode compared to cementless fixation, we should consider increasing the utilization of this technique.

Comparative in vitro evaluation of microgap in titanium stock versus cobalt-chrome custom abutments on a conical connection implant: Effect of crown cementation and ceramic veneering.

OBJECTIVE: To compare the implant-abutment connection microgap between computer-aided design and computer-aided manufacturing (CAD/CAM) milled or laser-sintered cobalt-chrome custom abutments with or without ceramic veneering and titanium stock abutments with or without crown cementation. MATERIAL AND METHODS: Six groups of six abutments each were prepared: (1) CAD/CAM cobalt-chrome custom abutments: milled, milled with ceramic veneering, laser-sintered, and laser-sintered with ceramic veneering (four groups: MIL, MIL-C, SIN, and SIN-C, respectively) and (2) titanium stock abutments with or without zirconia crown cementation (two groups: STK and STK-Z, respectively). Abutments were screwed to the implants by applying 30 Ncm torque. All 36 samples were sectioned along their long axes. The implant-abutment connection microgap was measured using scanning electron microscopy on the right and left sides of the connection at the upper, middle, and lower levels. Data were analyzed using the Kruskal-Wallis test (p < .05). RESULTS: Mean values (µm) of the microgap were 0.54 ± 0.44 (STK), 0.55 ± 0.48 (STK-Z), 1.53 ± 1.30 (MIL), 2.30 ± 2.2 (MIL-C), 1.53 ± 1.37 (SIN), and 1.87 ± 1.8 (SIN-C). Although significant differences were observed between the STK and STK-Z groups and the other groups (p < .05), none were observed between the milled and laser-sintered groups before or after ceramic veneering. The largest microgap was observed at the upper level in all groups. CONCLUSIONS: Titanium stock abutments provided a closer fit than cobalt-chrome custom abutments. Neither crown cementation nor ceramic veneering resulted in significant changes in the implant-abutment connection microgap.

[Study on the pressure on ceramic veneers during cementation]. / Izuchenie velichiny davleniya na keramicheskie viniry vo vremya ikh tsementirovaniya.

OBJECTIVE: The aim of the study is measuring the magnitude and determining the method of finger pressure exerted by doctors on ceramic veneers during their fixation. MATERIAL AND METHODS: A simulation model was designed in order to measure the volume of finger pressure. Veneers were produced for 2 central incisors. Doctors alternately placed veneers on the model and applied pressure on them for 20 seconds simulating the clinical stage of cementing. The operator recorded the maximum readings of the scales and entered the result on the research protocol. In addition, it was recorded which finger the doctor exerts on the veneer during its cementing to ensure a tight fit: thumb or index finger. RESULTS: The values obtained during cementation of 54% doctors ranged up to 1 kg, 27% of doctors from 1 to 2 kg and only 19% more than 2 kg. 80% of doctors applied the main pressure on the veneer using their thumb, while the pressure force was 1.4 kg. For those doctors who pressed the veneer to the tooth with their index finger, the impact value was 0.8 kg. CONCLUSION: The finger pressure on the veneer during cementation applied by dentists varies, the average pressure on the veneers was about 1.5 kg. The amount of pressure on cement during laboratory tests of cements for fixing veneers differs from clinical values many times. The development of a veneers fixation protocol, taking into account the conducted research, will ensure a reliable and accurate fit of the veneer at the stage of its cementing.

The effect of restorative material selection and cementation procedures on the durability of endocrowns in the anterior teeth: an in-vitro study.

OBJECTIVE: To investigate the fracture resistance and failure modalities of anterior endocrown restorations fabricated employing diverse ceramic materials, and bonded using various cementation methodologies. MATERIALS AND METHODS: Forty maxillary central incisors were divided into two main groups based on the ceramic materials used; GroupI (Zir): zirconia endocrwons (Zolid HT+, Ceramill, Amanngirrbach) and GroupII (E-Max): e-max endocrowns (IPS e.max CAD, Ivoclar Vivadent). Both groups were further split into two subgroups depending on the cementation protocols; subgroup IA "ZirMDP": endocowns cemented with MDP primer + MDP resin cement, subgroup IB (ZirNon-MDP): cemented with MDP primer + non-MDP resin cement, subgroup IIA (E-maxMDP): cemented with MDP primer + MDP resin cement, subgroup IIB (E-maxNon-MDP): cemented with MDP primer + non-MDP resin cement. (n = 10/subgroup). Endocrowns were manufactured using CAD/ CAM. Teeth were subjected to 10,000 thermal cycles. The fracture test was performed at 45o with a palatal force direction until the fracture occurred. Test results were recorded in Newton. The failure mode was examined using a stereomicroscope. A One-way ANOVA test was utilized to compare different groups regarding fracture strength values. Tukey`s Post Hoc was utilized for multiple comparisons. RESULTS: The comparative analysis of fracture strength across the diverse groups yielded non-significant differences, as indicated by a p-value exceeding 0.05. Nonetheless, an observable trend emerged regarding the mode of failure. Specifically, a statistically significant prevalence was noted in fractures localized within the endocrown/tooth complex below the cementoenamel junction (CEJ) across all groups, except for Group IIB, "E-max Non-MDP," where fractures within the endocrown/tooth complex occurred above the CEJ. CONCLUSIONS: Combining an MDP-based primer with an MDP-based resin cement did not result in a significant effect on the anterior endocrown fracture strength. CLINICAL RELEVANCE: Regardless of the presence of the MDP monomer in its composition, adhesive resin cement achieved highly successful fracture strength when used with MDP-based ceramic primers. Additionally, ceramic materials exhibiting elastic moduli surpassing those of dentin are discouraged due to their propensity to induce catastrophic fractures within the tooth structure.

Are there patients with an intracapsular fracture of the hip who may benefit from an uncemented hemiarthroplasty?

Aims: Cemented hemiarthroplasty is an effective form of treatment for most patients with an intracapsular fracture of the hip. However, it remains unclear whether there are subgroups of patients who may benefit from the alternative operation of a modern uncemented hemiarthroplasty - the aim of this study was to investigate this issue. Knowledge about the heterogeneity of treatment effects is important for surgeons in order to target operations towards specific subgroups who would benefit the most. Methods: We used causal forest analysis to compare subgroup- and individual-level treatment effects between cemented and modern uncemented hemiarthroplasty in patients aged > 60 years with an intracapsular fracture of the hip, using data from the World Hip Trauma Evaluation 5 (WHiTE 5) multicentre randomized clinical trial. EuroQol five-dimension index scores were used to measure health-related quality of life at one, four, and 12 months postoperatively. Results: Our analysis revealed a complex landscape of responses to the use of a cemented hemiarthroplasty in the 12 months after surgery. There was heterogeneity of effects with regard to baseline characteristics, including age, pre-injury health status, and lifestyle factors such as alcohol consumption. This heterogeneity was greater at the one-month mark than at subsequent follow-up timepoints, with particular regard to subgroups based on age. However, for all subgroups, the effect estimates for quality of life lay within the confidence intervals derived from the analysis of all patients. Conclusion: The use of a cemented hemiarthroplasty is expected to increase health-related quality of life compared with modern uncemented hemiarthroplasty for all subgroups of patients aged > 60 years with a displaced intracapsular fracture of the hip.

Clinical guidelines for posterior semidirect composite resin restorations: a case report with a 17-month follow-up.

Patients are always looking for conservative, esthetic, and long-lasting dental restorations, and the technique used directly influences the longevity of the treatment. The location of the restoration in the mouth and the extent of the decay influence the treatment choice. The larger the dimensions of the cavity preparation, the greater the difficulties in restoring the tooth using direct techniques. The semidirect technique, when indicated, can achieve satisfactory results. It is a relatively easy procedure, consisting of tooth preparation to receive an indirect restoration, fabrication of an alginate impression, fabrication of the composite resin restoration on a flexible cast, cementation, removal of excess cement, and occlusal adjustment. The aim of this case report is to present a viable alternative to direct and indirect restorations for posterior teeth with extensive decay. The article describes the extraoral semidirect technique for fabricating a composite resin restoration, highlighting its indications and discussing advantages and disadvantages.

Evidence-based clinical management of localised tooth wear and a repeatedly dislodged posterior crown utilising the Dahl Concept.

This clinical case report demonstrates the use of the Dahl Concept in the management of the repeated dislodgement of a posterior full coverage crown associated with a reduced restorative space. The described technique harnesses the addition of resin composite and a temporarily cemented provisional full coverage crown to create sufficient restorative space for the cementation of a definitive posterior full coverage crown restoration at the six-month review.

Intra-radicular retention with custom designed CAD-CAM fibRe-reinforced composite post-core: a dental technique.

A technique is outlined for utilising a polymeric composite reinforced with glass fibres in a three-dimensional mesh as a post-core in aesthetic cases. The clinical procedure involves obtaining an impression of the root canal space, scanning the definitive cast, and milling a fibre-reinforced composite post-core. Subsequently, the intra-radicular post-core is cemented using an adhesive resin cement. The use of custom-made computer-aided design-computer-aided manufacturing (CAD-CAM) fibre-reinforced composite post-core facilitates repairability, provides better adaptation to the root canal space, avoids uneven cement thickness, ensures chemical adhesion to resin cement, and promotes favourable aesthetics when combined with all-ceramic crowns.