Tissue response during self-ligating treatment

The effect of ligation methods on biofilm formation in patients undergoing multi-bracketed fixed orthodontic therapy - A systematic review

BACKGROUND

Many modifications to fixed orthodontic appliances have been introduced to manage biofilm formation. The aim of this review was to investigate elastomeric ligation in comparison with stainless steel ligation and self-ligation with regard to microbiological and clinical indicators of biofilm formation in patients wearing multi-bracketed fixed orthodontic appliances.

METHODS

The MEDLINE and the EMBASE databases were searched up to February 2021 and supplemented by additional manual searches of bibliographies. Parallel-group and split-mouth randomized controlled trials (RCTs) comparing different ligation methods were identified. The Cochrane Risk of Bias-2 tool was applied to assess the quality of evidence.

RESULTS

A total of 11 RCTs were included in this review. Nine RCTs compared self-ligation and elastomeric ligation; two compared elastomeric ligation and stainless steel ligation. The included studies had either some concerns or were at a high risk of bias. Qualitative assessment of the studies identified that there were no significant differences in biofilm formation between elastomeric ligation and self-ligation, but that stainless steel ligation was less susceptible to biofilm formation than elastomeric ligation.

CONCLUSIONS

There were no significant differences between self-ligation and elastomeric ligation for biofilm formation in patients wearing multi-bracketed fixed orthodontic appliances. Stainless steel ligation may accumulate less biofilm than elastomeric ligation; however, the clinical significance of the difference could not be evaluated. Further high-quality studies are required in order to determine which ligation method is better for managing biofilm formation in patients wearing multi-bracketed fixed orthodontic appliances.

Effect of orthodontic forces on levels of enzymes in gingival crevicular fluid (GCF): A systematic review

Objective:

Orthodontic force application releases multiple enzymes in gingival crevicular fluid (GCF) for activation, resorption, reversal, deposition of osseous elements and extracellular matrix degradation. The current systematic review critically evaluated all existing evidence on enzymes in orthodontic tooth movement.

Methods:

Literature was searched with predetermined search strategy on electronic databases (PubMed, Scopus, Embase), along with hand search.

Results:

Initial search identified 652 studies, shortlisted to 52 studies based on PRISMA. Quality assessment further led to final inclusion of 48 studies (13 moderately and 35 highly sensitive studies). Primary outcomes are significant upregulation in GCF levels of enzymes-aspartate aminotransferase (AST), alkaline phosphatase (ALP), matrix metalloproteinases (MMPs), lactate dehydrogenase (LDH), β-glucuronidase (βG), tartrate resistant acid phosphatase (TRAP), acid phosphatase (ACP) and down regulation in cathepsin B (Cb). Site specificity is shown by ALP, TRAP, AST, LDH, MMP9 with levels at compression site increasing earlier and in higher quantities compared with tension site. ALP levels are higher at tension site only in retention. A positive correlation of LDH, ALP and AST is also observed with increasing orthodontic force magnitude.

Conclusions:

A strong evidence of variation in enzymes (ALP, AST, ACP TRAP, LDH, MMPs, Cb) in GCF is found in association with different magnitude, stages and sites of orthodontic force application.

Finishing effectiveness of different archwires using SmartClip™ self-ligating brackets: a clinical study

OBJECTIVES

The aim of this clinical prospective trial was to evaluate finishing effectiveness of stainless steel (SS) archwires versus titanium molybdenum alloy (TMA) archwires using SmartClip™ self-ligating brackets.

SUBJECTS AND METHODS

Thirty-two patients were divided in two groups: a group of 21 (G1-SS) and a group of 12 (G2-TMA). The protocol consisted of two different finishing archwires coupled with self-ligating brackets: .019 × .025" SS archwires for G1-SS and .019 × .025" TMA archwires for G2-TMA. Lateral cephalometric radiographs obtained at the beginning (T1) and end (T2) of treatment were used to assess the changes in incisor inclination, and measurements of irregularity index (LII), interdental widths, arch length (AL) and arch depth (AD) were made on dental casts to investigate changes associated with crowding correction.

RESULTS

No significant differences from T1 to T2 were found for incisors proclination and AL changes. Statistically significant differences were found for LII (higher decrease in G1-SS), maxillary AD (higher increase in G1-SS) and three interdental maxillary widths (higher in G1-SS).

CONCLUSION

The statistically significant differences found were few and clinically negligible. Self-ligating brackets system coupled with .019 × .025" archwires showed good finishing effectiveness, but no clinically significant differences were found between SS and TMA.

Changes of substance P in the crevicular fluid in relation to orthodontic movement preliminary investigation

Substance P (SP) is a tachykinin released from both the central and the peripheral endings of primary afferent neurons and functions as a neurotransmitter. As a transmitter signaling pain, substance P is involved in nociception and is an extremely potent vasodilator. We found several studies about this neuropeptide especially in relation to parodontology and a few orthodontic reviews. This is because in the past the importance of this neuropeptide in dental element undergoing periodontal inflammation was observed. The aims of the present pilot study was to investigate whether the substance P was present in gingival crevicular fluid in dental elements undergoing orthodontic treatment with Invisalign technique compared to teeth belonging to the same series but not undergoing orthodontic movement. We analysed gengival crevicular fluid (GCF) collected from four young subjects, using a paper cone for a time of 60 seconds. The results showed that SP is present in the gengival sulcus in elements undergoing orthodontic forces during treatment with Invisalign technique and not in the control teeth. During the literature analysis, we have found a lot of papers describing involvement of SP in periodontitis and inflammatory diseases, but further studies are needed in order to demonstrate the role of this neuropeptide during teeth movement.