Background: Peri-implantitis due to infection of dental implants is a common complication that may cause significant patient morbidity. In this study, we investigated the antimicrobial potential of Sr(OH)₂ against different bacteria associated with peri-implantitis. Methods: The antimicrobial potential of five concentrations of Sr(OH)₂ (100, 10, 1, 0.1, and 0.01 mM) was assessed with agar diffusion test, minimal inhibitory concentration (MIC), and biofilm viability assays against six bacteria commonly associated with biomaterial infections: Streptococcus mitis, Staphylococcus epidermidis, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Escherichia coli, and Fusobacterium nucleatum. Results: Zones of inhibition were only observed for, 0.01, 0.1, and 1 mM of Sr(OH)₂ tested against P. gingivalis, in the agar diffusion test. Growth inhibition in planktonic cultures was achieved at 10 mM for all species tested (p < 0.001). In biofilm viability assay, 10 and 100 mM Sr(OH)₂ showed potent bactericidal affect against S. mitis, S. epidermidis, A. actinomycetemcomitans, E. coli, and P. gingivalis. Conclusions: The findings of this study indicate that Sr(OH)₂ has antimicrobial properties against bacteria associated with peri-implantitis.

The aim of this systematic review was to assess the current scientific evidence of the antimicrobial potential of strontium (Sr) when used to functionalize titanium (Ti) for oral applications. Out of an initial list of 1081 potentially relevant publications identified in three electronic databases (MEDLINE via PubMed, Scopus, and Cochrane) up to 1 February 2021, nine publications based on in vitro studies met the inclusion criteria. The antimicrobial potential of Sr was investigated on different types of functionalized Ti substrates, employing different application methods. Nine studies reported on the early, i.e., 6–24 h, and two studies on the late, i.e., 7–28 days, antimicrobial effect of Sr, primarily against Staphylococcus aureus (S. aureus) and/or Escherichia coli (E. coli). Sr-modified samples demonstrated relevant early antimicrobial potential against S. aureus in three studies; only one of which presented statistical significance values, while the other two presented only the percentage of antimicrobial rate and biofilm inhibition. A relevant late biofilm inhibition potential against S. aureus of 40% and 10%—after 7 and 14 days, respectively—was reported in one study. Combining Sr with other metal ions, i.e., silver (Ag), zinc (Zn), and fluorine (F), demonstrated a significant antimicrobial effect and biofilm inhibition against both S. aureus and E. coli. Sr ion release within the first 24 h was generally low, i.e., below 50 µg/L and 0.6 ppm; however, sustained Sr ion release for up to 30 days, while maintaining up to 90% of its original content, was also demonstrated. Thus, in most studies included herein, Sr-functionalized Ti showed a limited immediate (i.e., 24 h) antimicrobial effect, likely due to a low Sr ion release; however, with an adequate Sr ion release, a relevant antimicrobial effect, as well as a biofilm inhibition potential against S. aureus—but not E. coli—was observed at both early and late timepoints. Future studies should assess the antimicrobial potential of Ti functionalized with Sr against multispecies biofilms associated with peri-implantitis.

Objectives: To explore the antimicrobial potential of strontium (Sr)‐functionalized wafers against multiple bacteria associated with per‐implant infections, in both mono‐ and multispecies biofilms.Materials and Methods: The bactericidal and bacteriostatic effect of silicon wafers functionalized with a strontium titanium oxygen coating (Sr‐Ti‐O) or covered only with Ti (controls) against several bacteria, either grown as a mono‐species or multispecies biofilms, was assessed using a bacterial viability assay and a plate counting method. Mono‐species biofilms were assessed after 2 and 24 h, while the antimicrobial effect on multispecies biofilms was assessed at Days 1, 3, and 6. The impact of Sr functionalization on the total percentage of Porphyromonas gingivalis in the multispecies biofilm, using qPCR, and gingipain activity was also assessed.Results: Sr‐functionalized wafers, compared to controls, were associated with statistically significant less viable cells in both mono‐ and multispecies tests. The number of colony forming units (CFUs) within the biofilm was significantly less in Sr‐functionalized wafers, compared to control wafers, for Staphylococcus aureus at all time points of evaluation and for Escherichia coli at Day 1. Gingipain activity was less in Sr‐functionalized wafers, compared to control wafers, and the qPCR showed that P. gingivalis remained below detection levels at Sr‐functionalized wafers, while it consisted of 15% of the total biofilm on control wafers at Day 6.Conclusion: Sr functionalization displayed promising antimicrobial potential, possessing bactericidal and bacteriostatic ability against bacteria associated with peri‐implantitis grown either as mono‐species or mixed in a multispecies consortium with several common oral microorganisms.

Purpose: To investigate how varying ferrule heights and the number of glass fiber posts affect fracture resistance and behavior of endodontically treated maxillary first premolars with substantial loss of tooth structure.Materials and Methods: Twenty‐four extracted endodontically treated human maxillary first premolars were divided into three groups (n = 8) based on ferrule height and post number. The groups were as follows: premolars of 2 mm ferrule height that were restored with single posts (control group), premolars of 0.5 mm ferrule height that were restored with single posts in palatal canals (single‐post group), and premolars of 0.5 mm ferrule height that were restored with double posts in palatal and buccal canals (double‐post group). All groups were then restored with composite core and metal‐ceramic crowns cemented with zinc phosphate cement. All specimens were subjected to 10,000 thermal cycles at temperatures of 5°C and 55°C, as well as 1.2 million cyclic loadings of 49 N load at 1.2 Hz using a chewing simulator. The specimens were loaded to fracture in a universal testing machine and fracture behavior was examined under stereomicroscope and divided into restorable and unrestorable fracture modes. Fracture loads and modes were analyzed by one‐way ANOVA, Tukey's post hoc test, and Fisher's exact probability test (p ≤ 0.05).Results: The control group showed the highest mean fracture load (1127 ± 172) of all groups (p < 0.001). The specimens in the single‐post group showed numerically higher mean fracture load (522 ± 171) but with no significant difference compared to the ones in the double‐post group (518 ± 157; p > 0.967). In the control group, 75% of specimens showed unrestorable fractures compared to 50% and 12.5% in single‐post and double‐post groups. The specimens in the control group had similar unrestorable fractures, starting from the coronal part and extending obliquely to the cervical third of the root below resin level. Two specimens in the control group showed unrestorable fractures in the middle third of the root. No middle‐third root fractures were observed in single‐post and double‐post groups, and unrestorable fractures in both groups were similar to those of the control group. The single‐post group had two specimens with core‐post crown complex restorable fractures, while the control and double‐post groups had one specimen each. The remaining specimens showed cervical‐third root restorable fractures above resin level.Conclusion: The ferrule height significantly influences the fracture resistance of endodontically treated premolars compared to the number of placed posts. Nonetheless, more restorable fractures are seen in endodontically treated premolars restored with double posts than single posts regardless of ferrule height.

Background: This study’s objectives are to ascertain the frequency of congenital tooth missing and evaluate the relationship between gender and side characteristics. Method: This retrospective study involved participants who attended private dental clinics as well as a dental college in Hail, Saudi Arabia. Out of the 1,150 patients examined, 494 (220 males and 274 females) fulfilled the inclusion criteria. Different types of tooth agenesis were evaluated and classified into the following categories: mild (one or two teeth missing), moderate (three to five teeth missing), and severe (six or more teeth missing). The analysis did not include third molars. The existence of retained primary teeth was noted, along with any dental abnormalities accompanying tooth agenesis. Statistical analysis was conducted utilizing the chi-square test and Fisher’s exact test to explore possible relationships between variables. A significance level of 5% (alpha = 0.05) was utilized. Results: Out of the 1150 panoramic radiographs that were examined, 494 individuals (220 (44.5%) males and 274 (55.5%) females) met the criteria for inclusion. The prevalence of congenitally missing permanent teeth was 65 (13.2%) in the study sample. The prevalence of congenitally missing teeth were more incidence in maxilla 36 (56.3%) than mandible 28 (43.8%). There is statistically significant association between the occurrence of congenitally missing teeth and gender or arch (p < 0.05). The prevalence of dental anomalies was similar in both sides. There are not a statistically significant association (p > 0.05) between the occurrence of congenitally missing teeth and side. The second premolar was the most commonly missing (7.3%). The retained deciduous teeth was shown to be the most common dental anomaly, with a prevalence of 15 (23.4%). Conclusions: The prevalence of congenitally missing teeth fell within the range reported in previous studies. Second premolars were the most frequently congenitally missing teeth, with maxillary teeth more commonly affected than mandibular ones.