Effect of moisture, saliva, and blood contamination on the shear bond strength of brackets bonded with a conventional bonding system and self-etched bonding system

Abstract Background: The success of bonding brackets to enamel with resin bonding systems is negatively affected by contamination with oral fl uids such as blood and saliva. The new self-etch primer systems combine conditioning and priming agents into a single application, making the procedure more cost effective. Objective: The purpose of the study was to investigate the effect of moisture, saliva and blood contamination on shear bond strength of orthodontic brackets bonded with conventional bonding system and self-etch bonding system. Continue reading Effect of moisture, saliva, and blood contamination on the shear bond strength of brackets bonded with a conventional bonding system and self-etched bonding system

Effect of Load Deflection on Corrosion Behavior of NiTi Wire

ABSTRACT

For dental orthodontic applications, NiTi wires are used under bending conditions in the oral environment for a long period. The purpose of this study was to investigate the effect of bending stress on the corrosion of NiTi wires using potentiodynamic and potentiostatic tests in artificial saliva. The results indicated that bending stress induces a higher corrosion rate of NiTi wires in passive regions. Continue reading Effect of Load Deflection on Corrosion Behavior of NiTi Wire

Effect of rapid maxillary expansion on the vertical dimension.

Written by : Dr. Rania Alraddadi.

Dear all,

Another topic that we constantly discuss is the effect of rapid maxillary expansion on the vertical dimension.

It was shown that in the long term the  side effects on the vertical dimension are actually minimum.

Here is a systematic review:

http://libdigi.unicamp.br/document/?down=32604 that argues the real long term benefits claimed by bonded RPE users.

According to them, even after the use of bonded RPE, some vertical adverse effects are inevitable. They explained that the vertical change is not caused by buccal tipping of maxillary molars only (which can be controlled by using bonded RPE) but also caused by the whole maxilla being displaced downward. So it was suggested that in cases where vertical dimension is critically sensitive, the use of vertical pull chin cup (or I would also add high pull HG) might be an option.

Explanation of how mandibular expansion follows the Maxillary.

Written by : Dr. Rania Alraddadi .

Dear all,

Today we discussed expansion and mentioned that in most of the cases mandibular arch “follows” the expansion of the maxillary arch and so we rarely use expansion appliances in the mandible.

I just wanted to share the explanation to help the junior residents and refresh the info for the rest of us.

According to Hass, this happens due to several factors:

1- The forces of occlusion were altered by expansion so that the normal lingual vector on the mandibular teeth was lost and the lateral movement of maxilla widened the area of attachment of buccal musculature which caused change in balance between buccal surface and the tongue (a decrease in pressure from the cheeks as result of upper arch expansion will allow the tongue to exert more pressure thus uprighting and expanding lower arch).

2- Thickness of the appliance (3 quarters of an inch) might have caused the tongue to be in a lower position thus exerting even more lingual pressure on mandibular teeth.

Here is the original article:

http://www.angle.org/doi/pdf/10.1043/0003-3219(1961)031%3C0073:reotmd%3E2.0.co;2

Thank you.

Assessment of Lip Position

Written By : Dr. Rania AlRaddadi .

Dear all,

Here is a quick reminder & an illustration + some old but nonetheless classic references.

In ceph and photographic analysis there are many lines that have been introduced to assess lip position: Ricketts E line, Steiner’s S line, Holdaway’s H line, Burstone’s B line to name a few.. But actually the ones that are mostly used are the E line and the S line.
Continue reading Assessment of Lip Position

STCA (soft tissue cephalometric analysis)

Written by : Dr. Rania AlRaddadi ..

Dear all,

Attached is an article that discusses STCA (soft tissue cephalometric analysis).

I think some of us already came across it but I thought I would share it anyway.

Now I understand that we always say that ceph readings are only numbers and that we should always look at the patient clinically, but I still think that this is a good article because most of the time we rely on photographs to diagnose which are not always standard or accurate. Using the ceph (which we already take routinely for each patient) might aid in our diagnosis process.
Continue reading STCA (soft tissue cephalometric analysis)

Analysis of intra-arch and interarch measurements from digital models with 2 impression materials and a modeling process based on cone-beam computed tomography

 

Abstract :

Introduction: Study models are an essential part of an orthodontic record. Digital models are now available. One option for generating a digital model is cone-beam computed tomography (CBCT) scanning of orthodon- tic impressions and bite registrations. However, the accuracy of digital measurements from models generated by this method has yet to be thoroughly evaluated. Methods: A plastic typodont was modified with reference points for standardized intra-arch and interarch measurements, and 16 sets of maxillary and mandibular vinyl- polysiloxane and alginate impressions were made. A copper wax-bite registration was madewith the typodont in maximum intercuspal position to accompany each set of impressions. Continue reading Analysis of intra-arch and interarch measurements from digital models with 2 impression materials and a modeling process based on cone-beam computed tomography

Evaluation of CBCT Digital Models and Traditional Models Using the Little’s Index

 

ABSTRACT

Objective: To determine if measurements obtained from digital models from cone beam computed tomography (CBCT) images were comparable to the traditional method of digital study models by impressions.

Materials and Methods: Digital models of 30 subjects were used. InVivoDental (Anatomage, San Jose, Calif) software was used to analyze CBCT scans taken by a Galileos cone beam scanner (Sirona, Charlotte, NC) with a field of view of 15 3 15 3 15 cm3 and a voxel resolution of 0.125 mm. OrthoCAD (Cadent, Fairview, NJ) software was used to analyze impression scans of patients at different stages of orthodontic treatment. Impressions were taken using alginate and were mailed to OrthoCAD for digital conversion. The scans were then electronically returned in digital format for analysis. Continue reading Evaluation of CBCT Digital Models and Traditional Models Using the Little’s Index

How Systematic reviews are conducted?

By : Dr. Hani Alhebshi.

A systematic review is simply a structured and organized way to review many articles on specific topic and collecting their results and analyzing them with or without statistical methods; to reach a better conclusion on that topic under investigation.
If statistical methods were used ; It is called “Meta-analysis“.

For example :
If we want to make a systematic review on whether there is a relation between third molar impaction and late lower arch crowding , we raise the question : Is there a relation between them ?
Then we determine inclusion and exclusion criteria of papers that we are going to collect. They must be relevant to our topic. If articles found during our search has not matched our inclusion criteria ; they are ignored to others that match.
Then we organize data in tabular forms and analyze their results.
Analysis can summerize the net conclusion of whether they support or refute presence of any relation between molar impaction and lower arch crowding. Continue reading How Systematic reviews are conducted?

Sequence of archwires of 2 bracket prescriptions (0.018 and 0.022 slots)

This is a general guideline of the sequence of archwires during treatment which can be modified according to the clinical situation.

( Summerized from a lecture of Dr. Zuhair Bakhsh ).

*For 0.018 x 0.025 slot brackets

Phase I (Alignment&Leveling):

1.0.014 Niti

2.0.016 Nitti
Continue reading Sequence of archwires of 2 bracket prescriptions (0.018 and 0.022 slots)

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