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Retention of Bioflx, Zirconia, and Stainless Steel crowns using two different luting cements in primary molars: an in vitro study
Background
Different crown types are used for the full-coverage restoration of primary teeth with extensive caries. Bioflx crowns are hybrid polymer-resin crowns designed to combine the benefits of Stainless Steel and Zirconia. The longevity and clinical efficacy of dental restorations are significantly affected by crown retention. We aim to assess the retention of Bioflx, Zirconia, and Stainless Steel crowns using two different luting materials.
Methods
Fifty-four (
n
= 54) freshly extracted mandibular second primary molars were divided into three main groups (
n
= 18): Bioflx crowns, Zirconia crowns, and Stainless Steel crowns (SSCs). Each group was further subdivided into two subgroups (
n
= 9), using either Conventional Glass Ionomer luting cement (GIC) or Resin Modified Glass Ionomer luting cement (RMGIC). A retention test was performed to determine the retentive force required for crown removal after the samples underwent 2,000 cycles of thermocycling. A stereo light microscope was used to examine the debonding failure. Data were analysed using two-way analysis of variance (ANOVA) and Pearson’s chi-square test.
Results
Stainless Steel crowns exhibited the highest retention in both subgroups (GIC = 307.44 ± 53.58 N, RMGIC = 324.11 ± 52.04 N). Bioflx crowns outperformed Zirconia crowns (Bioflx: GIC = 138.11 ± 30.87 N, RMGIC = 218.11 ± 34.61 N; Zirconia: GIC = 35.50 ± 5.14 N, RMGIC = 131.78 ± 11.91 N). All differences between the GIC and RMGIC subgroups were significant (
p
< 0.001), except for Stainless Steel crowns (
p
= 0.5). RMGIC had greater retention values than GIC in all groups, and the difference was significant (
p
< 0.001), except for the SCCs group (
p
= 0.5).
Conclusions
Stainless Steel crowns showed the highest retention across all tested luting cements, followed by Bioflx crowns, which exhibited superior retention compared with Zirconia crowns. RMGIC showed superior retention compared with GIC.
Journal Article
The crown on your head
A story in rhyme, lovingly expressing that every child is born with a crown of features that gives him or her unique value.
Book
Treatment outcomes after uncomplicated and complicated crown fractures in permanent teeth
Objectives
The objectives of this retrospective clinical study were to describe characteristics of crown fractures in permanent teeth and to investigate the survival of pulp vitality and restorations in uncomplicated and complicated crown fractures.
Materials and methods
This retrospective study collected information from patients suffering from dental trauma who were treated between January 2004 and June 2017. The study population consisted of 434 patients (253 males/181 females; mean age 20.7 years) with 489 uncomplicated and 127 complicated crown fractures. The Kaplan-Meier survival curves and Cox proportional hazard regression analyses were performed to explore the data statistically.
Results
The mean observation time was 522 days. Uncomplicated crown fractures without luxation showed a higher success rate of 82.3% (345/419) than complicated crown fractures without luxation (72.3%, 73/101). An additional luxation in uncomplicated crown fractures resulted in significantly reduced success rates in terms of survival of the pulp and restoration. Direct restorations survived significantly better independent of the fracture mode than did adhesively reattached crown fragments. No superiority of mineral trioxide aggregate or calcium hydroxide as pulp capping agent in complicated crown fractures was documented. Approximately 85.5% of all complications occurred within 2 years after the accident.
Conclusion
The treatment of crown fractures resulted mostly in successful outcomes and only a moderate number of complications were observed.
Clinical relevance
Primary dental management of crown fractures should follow recently published clinical guidelines, and close monitoring over at least 2 years seems to be justified.
Journal Article
The Snow Fairy
It is time for the winter Sparkle Ball, so when Billy the badger has the Snow Fairy's crown snatched from his paws by a greedy magpie, who loves sparkly things, it is up to the Superfairies to retrieve it and save the Ball.
Book
Thermomechanical aging effects on vertical marginal gap and fracture resistance: a comparative study of Bioflx and traditional pediatric crowns
Background
Various types of crowns are used for full-coverage restoration of primary teeth affected by caries, developmental defects, or after pulp therapy. Prefabricated Stainless Steel and Zirconia crowns are commonly utilized. Bioflx crowns, which blend the properties of Stainless Steel and Zirconia, provide a flexible and aesthetically pleasing alternative.
Aim
This study aimed to evaluate the vertical marginal gap and fracture resistance of Bioflx pediatric crowns compared to Zirconia and Stainless Steel crowns following thermomechanical aging.
Methods
This in-vitro study was conducted using mandibular second primary crowns of three different materials (
n
= 30). Crowns were divided into three groups; Zirconia crowns group (
n
= 10, Nu Smile, USA), Bioflx crowns group (
n
= 10, Nu Smile, USA) and Stainless Steel crowns group (
n
= 10, Nu Smile, USA). The crowns were cemented onto standardized acrylic resin dies and subjected to thermomechanical aging. Vertical marginal gap measurements were obtained using a USB digital microscope with an integrated camera, while fracture resistance was assessed with a universal testing machine. Data were analyzed for outliers and tested for normality using the Shapiro-Wilk or Kolmogorov-Smirnov tests, with statistical significance set at 0.05.
Results
Significant differences were observed in the vertical marginal gaps among the groups after cementation and thermomechanical aging (
P
= 0.013 and
P
= 0.001, respectively). Zirconia crowns exhibited the largest average marginal gap, followed by Bioflx and Stainless Steel crowns. Stainless steel crowns demonstrated the highest fracture resistance, followed by Bioflx crowns, while Zirconia crowns showed the lowest.
Conclusions
Bioflx crowns exhibit the largest vertical marginal gap but show greater fracture resistance compared to Zirconia crowns, although they are still less resistant than Stainless Steel crowns after undergoing thermomechanical aging.
Journal Article
Mission paw
Chase and his PAW patrol friends come to the rescue when the royal crown of Barkingburg is stolen.
Book
Comparative clinical performance of stainless steel, zirconia, and Bioflx crowns in primary molars: a randomized controlled trial
Background
Choosing the appropriate crown type for primary molars is essential for effective restoration and oral health. Stainless steel crowns are durable and cost-effective, making them suitable for extensive decay. Zirconia crowns offer esthetic advantages, while Bioflx crowns require less preparation and provide optimal appearance. Understanding the benefits and limitations of each type ensures optimal outcomes for young patients. The purpose of the study was to clinically compare these three types of crowns for primary molars regarding plaque accumulation, debonding rate, crown substance loss and gingival health.
Materials and methods
Registered with clinicalTrials.gov (NCT06706167), this study included 75 children (43 males, 32 females; mean age: 6.3 years) divided into 3 groups: Group A (stainless steel crowns), Group B (zirconia crowns), and Group C (Bioflx crowns), with 25 patients each. Plaque index, crown survival regarding debonding rate and substance loss, and gingival index were evaluated at baseline, 6, and 12 months.
Results
At 6- and 12-month follow-ups, no significant differences were observed among groups. However, zirconia crown demonstrated better results in terms of plaque accumulation and gingival health. Conversely, stainless steel crown showed marginally better performance in crown retention.
Conclusion
All crowns showed acceptable clinical performance. Factors such as crown retention, esthetics and biocompatibility should be considered when selecting the most appropriate crown for each molar.
Trial registration
The study was registered on ClinicalTrials.gov, with the registration number NCT06706167 with registration date 26,112,024.
Journal Article
Clinical and radiographic performance of preformed zirconia crowns and stainless-steel crowns in permanent first molars: 18-month results of a prospective, randomized trial
Background
The treatment of young permanent first molars with extensive carious tissue loss may often require restoration with preformed crowns. This study compared the clinical and radiographic performance of stainless-steel crowns (SSCs) and preformed zirconia crowns (ZCs).
Methods
Forty-eight molar incisor hypomineralisation (MIH)- or caries-affected permanent molars in 20 healthy patients between 6–13-year-old were randomly divided into ZC and SSC groups (n = 24 teeth/group) in a split-mouth design. The oral hygiene levels of patients were assessed using Greene and Vermillion simplified oral hygiene index (OHI-S). Plaque accumulation and gingival health were evaluated using the Silness&Löe plaque index (PI) and Löe&Silness gingival index (GI), respectively. Clinical retention, marginal extension level, marginal adaptation of crowns and wear of the antagonist teeth were assessed at baseline, 1, 6, 12 and 18 months. The radiological assessments for evaluating the marginal adaptation of crowns and periapical pathology of crowned teeth were performed at 6 and 12 months. The data were analyzed using Kaplan–Meier analysis, Mann–Whitney U test, and two-way ANOVA.
Results
A total of forty teeth in 17 children were evaluated for 18 months. ZCs had significantly lower gingival and plaque index values than teeth restored with SSCs during all evaluation periods (p < 0.05). Neither crown type resulted in clinically-detectable wear on opposing dentition or periapical pathology. One ZC was lost at 13 months, while all SSCs survived in function clinically. The cumulative survival rates of ZCs and SSCs were 95.2% and 100% respectively.
Conclusions
Both ZCs and SSCs showed high clinical retention rates in young permanent molars. ZCs had lower plaque accumulation and better gingival health than SSCs, which were consistently associated with mild gingival inflammation.
Clinical Trial Registration Number
NCT05049694.
Journal Article