Orthodontic microabrasive reproximation

Comparative Evaluation of Dental Enamel Microhardness Following Various Methods of Interproximal Reduction: A Vickers Hardness Tester Investigation

Interproximal enamel reduction, also known as stripping, is a common orthodontic procedure that reduces the mesiodistal diameter of teeth, allowing for a balance of available space in dental arches. The aim of this study was to assess the enamel surface microhardness resulting from the application of currently available methods for interproximal reduction. Forty-two extracted human permanent teeth were divided into six different groups, each subjected to a therapeutic stripping procedure using various methods (i.e., diamond burs, abrasive strips of 90 μm, 60 μm, 40 μm, and 15 μm, and abrasive discs). Stripping was performed by a single individual in accordance with the manufacturers' recommendations for the various systems used. One of the proximal faces of the tooth underwent IPR, while the other side remained untreated for control. The hardness of the enamel surface was measured using a Vickers hardness tester. The control group achieved the hardest enamel surface (354.4 ± 41.02 HV1), while the lowest was observed for enamel surfaces treated with 90 µm abrasive strips (213.7 ± 118.6). The only statistically significant difference was identified in comparisons between the values measured for the control group and those obtained after stripping with diamond burs (p = 0.0159). Enamel microhardness varied depending on the stripping instrument used, but no statistically significant differences were found (p > 0.05). Optimal microhardness values, close to those of healthy enamel, were achieved after mechanical treatment with 15 µm abrasive strips and abrasive discs. Dental stripping is a safe therapeutic procedure that has a relatively minor influence on the microhardness of surface enamel.

The Role of Interproximal Reduction (IPR) in Clear Aligner Therapy: A Critical Analysis of Indications, Techniques, and Outcomes

Interproximal reduction (IPR) has become a standard practice in orthodontic treatment, particularly in the clear aligner therapy. It became an integral part of the digital plan when using clear aligners. Given the irreversible nature of IPR, precise planning and performance is essential. This article aims to analyze and summarize the existing literature on IPR in the context of clear aligners. The goal is to help clinicians to gain essential knowledge for safely and effectively navigating IPR. The review critically examines different perspectives found in the literature, covering indications, methods, and outcomes. Topics exploring the impact of IPR on treatment outcomes include space gaining, addressing tooth size discrepancies, tooth shape adjustments, resolving malocclusion, and enhancing aesthetics. Emphasizing precision of the procedure by the clinician and awareness of contraindications, the article also discusses the impact of IPR on patients. This includes considerations like increased pulp temperature, susceptibility to cavities due to changes in enamel roughness, effects on soft tissues, and post-IPR tooth sensitivity.

Does surface enamel composition and characteristics vary with inter proximal enamel reduction?

OBJECTIVE

This study aimed to evaluate the chemical composition of the proximal enamel surface and the surface characteristics subjected to different extents of interproximal reduction (IPR) in a clinical setting.

MATERIALS AND METHODS

Premolars of orthodontic patients which were designated for extraction were subjected to .2 mm, .3 mm, and .5 mm of IPR. After 1 month, the teeth were extracted and the teeth were subjected to scanning electron microscope (SEM) and energy-dispersive x-ray spectroscopy (EDX).

RESULTS

The SEM images of the three experimental groups (taken at magnification of 500 × and 2000 ×) showed that the enamel surfaces were irregular and rough compared to the honey comb appearance of the unstripped group. Small areas of erosion of enamel surface were seen in Group I (0.2 mm) under 2000 × magnification compared to Group IV (control) which showed typical arrangement of enamel rods in alternating orientation. The enamel surfaces of stripped and unstripped enamel contained calcium, phosphorus, carbon, oxygen, and nitrogen. The differences were not statistically significant and neither were the calcium phosphorous stoichiometric ratios between the four groups.

CONCLUSIONS

On analyzing the surface characteristics of enamel using SEM between the stripped and unstripped surfaces, there were irregularities and roughness seen in stripped surface whereas honey comb pattern was observed in unstripped enamel surfaces. The elements found in unstripped and stripped enamel surfaces were calcium, phosphorous, carbon, oxygen, and nitrogen. Although the calcium and phosphorus were high in the 0.5 mm IPR group, the difference between stripped and unstripped enamel surfaces was statistically not significant.

CLINICAL RELEVANCE

There have been concerns that IPR can remove the superficial mineral-rich layer making the deeper layers more susceptible to carious attack. No study has evaluated the mineral content in different layers of enamel in response to IPR in vivo and this study found no significant difference between pristine enamel and enamel subjected to IPR. The results of this study strengthen the validity of the clinical protocol employed.

Evaluation of Enamel Surfaces after Different Techniques of Interproximal Enamel Reduction

According to the literature, interproximal enamel reduction (IER) has become a consolidated technique used in orthodontic treatments to gain space in particular situations such as dental crowding, non-extractive therapies, tooth-size discrepancies, and prevention of dental relapse. There are different methods to realize stripping, and enamel surfaces resulting after this procedure can be analyzed with SEM. The aim of this study was to analyze how different devices of IER leave the surface of the teeth. One hundred and sixty freshly extracted, intact human lower incisors were included in the study, fixed in a plaster support, and then processed with four different techniques of enamel reduction and finishing. Then, they were divided randomly into eight groups (A1-A2, B1-B2, C1-C2, D, and E), each containing twenty teeth. The A, B, and C groups were divided into two subgroups and then all the teeth were observed at SEM. Each digital image acquired by SEM showed that there were streaks on the surfaces, due to the cutter used. The results of this study showed that only group C2 (tungsten carbide bur followed by twelve steps of medium-fine-ultrafine 3M Soft Lex disks) has a few line, which is very similar to group E (untreated group), while the other groups have a lot of lines and show a rougher final surface.

Manual and mechanical stripping-induced enamel roughness and elemental composition in vivo

Objectives

Interproximal enamel reduction (IPR) is routinely used in orthodontics to generate small to moderate amounts of space within the dental arch. Aim of this ex vivo study was to evaluate the effect of two different IPR systems on the enamel surface’s waviness, roughness, and elemental composition after 6 months of intraoral exposure.

Materials and methods

Fifteen orthodontic extraction patients were included in the present study. The 39 healthy premolars, which were scheduled to be extracted, were subjected to IPR at least 6 months before their extraction. IPR was performed on their mesial side with two different methods: (1) instrumented method with the Ortho-Strips system (on handpiece) and (2) manually with the Intensiv ProxoStrip (strips)—each with four different grits for contouring, finishing, and polishing. The distal side of each premolar served as its own internal control. Treated and untreated tooth surfaces were evaluated by optical profilometry, Raman, and scanning electron microscope/X-ray energy-dispersive (EDX) analyses. Data were analysed with descriptive statistics and generalized linear models at alpha = 5%.

Results

Both IPR methods significantly reduced the waviness of the enamel surface (P < 0.001), with manual IPR leading to smaller waviness reductions than the instrumented IPR (P ≤ 0.001). On the other side, both IPR methods led to a significant increase in enamel surface roughness (P < 0.001), with no significant differences between IPR methods. EDX and Raman analyses did not demonstrate any alterations on elemental composition of enamel after at least 6 months of intraoral exposure.

Conclusions

Both stripping systems led to a flatter but rougher enamel surface. Further polishing is needed to restore the initial enamel smoothness. The elemental composition of the stripped enamel returns to the baseline level after 6 months of intraoral exposure.

Association between incisor positions and amount of interdental stripping in patients undergoing orthodontic treatment

INTRODUCTION

The study aimed to investigate the effect of a nonextraction treatment approach with interdental stripping (IDS) on the dentofacial structures in patients with dental and skeletal Class I, II, and III malocclusions.

METHODS

A total of 60 patients with mild-to-moderate crowding of the teeth and nonsevere skeletal malocclusion were included and divided into 3 groups: Class I, Class II, and Class III groups (n = 20 per group). In all patients, nonextraction orthodontic treatment was administered, and those who underwent IDS at the jaw quadrants as needed were evaluated. For pretreatment and posttreatment evaluation, lateral cephalometric radiography and 3-dimensional dental model scans were acquired for each patient. For statistical analysis, paired-samples t test and 1-way analysis of variance with Tukey post-hoc test were used for parametric variables, whereas the Wilcoxon paired signed rank test and Kruskal-Wallis test with Dunn post-hoc test were used for nonparametric variables.

RESULTS

An increase in the maxillary incisor angle was observed in patients with Class I and Class III malocclusions, whereas a decrease was observed in patients with a Class II malocclusion (P < 0.05). Mandibular incisor angles were significantly increased in the Class II malocclusion group (P < 0.05) but unchanged in the other groups. IDS was more frequently applied to the posterior aspect of the maxilla and mandible in patients with a Class II malocclusion than in patients with other malocclusion types, and the amount of IDS at the anterior aspect of the mandible was significantly higher in the Class III group.

CONCLUSIONS

Combined nonextraction orthodontic treatment and IDS yielded successful treatment outcomes. IDS application was localized to different jaw regions according to the different malocclusion types.

Quantitative assessment of interproximal tooth reduction performed as part of Invisalign® treatment in 10 orthodontic practices

Background

Interproximal reduction (IPR) is a treatment option for orthodontic space gain. The attainment of prescribed objectives in aligner treatment may require IPR that is accurately performed both qualitatively and quantitatively.

Objective

This study assesses the in vivo accuracy of IPR carried out in 10 orthodontic practices as a method of orthodontic space creation.

Methods

A comparison of proposed and achieved amounts of IPR completed (accuracy), the accuracy of IPR within and between upper and lower dental arches, and the accuracy of IPR within and between posterior and anterior arch segments were performed using 3-dimensional digital study models gained via Align’s® ClinCheck.

Results

The findings indicated that IPR was routinely underperformed by all practices studied. On average, the amount of IPR achieved represented only 44.0% of the total prescribed per tooth in the sample assessed, with a mean discrepancy of 0.16 mm per tooth. There were statistically significant differences only between the overall anterior and posterior groups (p < 0.01) and between maxillary anterior and maxillary posterior groups (p < 0.01); however, these were not clinically significant. Significant differences in IPR performance were noted between different orthodontic practices.

Conclusions

This study demonstrates that the clinical performance of IPR in 10 orthodontic practices consistently fails to achieve the prescribed amount often by large variations. The effect of this under-performance on clinical outcomes remains to be quantified.

Depth of acid penetration and enamel surface roughness associated with different methods of interproximal enamel reduction

Objectives

To assess and compare the enamel surface quality after interproximal enamel reduction (IPR) was performed with different systems and to study the relation between acid penetration depth and enamel surface quality as well as the importance of remineralization.

Methods

Sixty-five extracted teeth were randomly allocated to five experimental groups: untreated control, manual with New Metal Strips, mechanical with oscillating segment (OS) discs, Safe-Tipped Bur Kit, and the Ortho-Strip, followed by 30 s of polishing with the Softflex system and the Compo-system after treating the tooth with OS discs. Mesial surfaces were demineralized for 24 h and distal surfaces were subjected to interchanging demineralization and remineralization cycles of 24 h each for 18 days. The analysis was carried out by profilometry, scanning electron microscopy, and polarization microscopy.

Results

After IPR and polishing, enamel roughness was reduced for all systems tested except for the Essix Safe-Tipped Bur Kit. Subsequent demineralization increased enamel roughness in all groups except controls beyond the original level prior to IPR except for IPR with New Metal Strips or Ortho-Strips and subsequent polishing. Cyclic demineralization and remineralization for 18 days yielded a reduction in acid penetration depth and an increase in surface smoothness, which correlated with each other only for controls and treatment with New Metal Strips or Ortho-Strips.

Conclusions

Manual IPR, using New Metal Strips and, even more, the oscillating IPR system Ortho-Strips, yielded smoother interproximal enamel surfaces and less acid penetration depth than the IPR systems with OS discs and the Safe-Tipped Bur Kit after polishing and 18 days of cyclic demineralization and remineralization. Irrespective of the IPR procedure, proper remineralization of IPR-treated surfaces is advisable to reduce caries susceptibility.

Comparison of Interproximal Reduction Techniques and Proximal Strips: An Atomic Force Microscopic and Confocal Microscopic Study

Objective: A vivo study was conducted to evaluate the surface roughness produced by two different methods: hand-held mechanical and air-rotor stripping and also by HORICO and Ortho-Organizer strips (Bengaluru, India), before and after polishing with 3M Sof-Lex Finishing Strips under Atomic Force Microscope.

Methodology: Study included 44 proximal surfaces of extracted premolars divided into a control group and 3 experimental groups with 12 surfaces in each. Hand-held mechanical stripping was done by 40 passages of 6 cm long abrasive strips and air-rotor stripping using high-speed air-rotor turbine hand piece. Polishing was done using 3M Sof-Lex finishing strips. Reduced teeth samples were viewed under Atomic Force Microscope and the proximal strips under Confocal microscope for surface roughness.

Results: Air-rotor stripping produced statistically significant more surface roughness compared to the mechanical reduction technique ( P = .01). There was no significant difference between the roughnesses produced by 2 different proximal strips. Tooth surface after IPR with polishing had less roughness compared to unpolished surface. There was no mean difference between the wear of proximal strips.

Conclusion: The mechanical reduction technique of interproximal surface produces less surface roughness compared to air-rotor stripping. Polishing with 3M Sof-Lex strips after reduction irrespective of the technique and material used gives smoother surface than even normal enamel.

Comparison of the abrasive properties of two different systems for interproximal enamel reduction: oscillating versus manual strips

Background

The aim of the present investigation was to evaluate enamel reduction efficiency, abrasive property decay, and enamel effects between oscillating mechanical and manual systems for interproximal enamel reduction (IPR).

Methods

Three oscillating strips and three manual strips were tested on twelve freshly extracted premolars blocked in an acrylic cylinder pot by means of a material testing machine. Each strip underwent one test of 8 cycles (30 s each). Both abrasive tracks and teeth surfaces were qualitative evaluated before and after IPR by means of SEM analysis. Efficiency and abrasive property decay of both IPR systems were investigated by the amount of enamel reduction within the eight-cycle testing. Independent t-test was used to evaluate differences in variables between the two systems.

Results

Mechanical IPR system showed higher efficiency in terms of enamel reduction (p < 0.005) when compared with manual IPR system (0.16 mm and 0.09 mm, respectively). Quantity of removed enamel decreased throughout the 8 cycles for both systems. Less presence of enamel debris and detachment of abrasive grains were observed on mechanical strips rather than manual strips. SEM analysis revealed more regular surface of teeth undergone mechanical IPR procedures.

Conclusion

Oscillating diamond strips showed more controlled efficiency when compared with the manual IPR system leading to a more regular enamel surface.

Quantitative evaluation of the progressive wear of powered interproximal reduction systems after repeated use : An in vitro study

PURPOSE

To evaluate the residual surface roughness of 5 common diamond-coated interproximal reduction (IPR) systems after consecutive in vitro applications in relation to system, diamond grain size, and instrument thickness.

METHODS

IPR was performed on 80 extracted human incisors using motor-driven strips and discs under predefined conditions. The IPR auxiliaries were applied at 5 consecutive sessions of 20 s on intact interproximal surfaces, and the surface profile (R_a, R_z, R_max) was analyzed at baseline and after each session with an optical profilometer.

RESULTS

No overall significant difference in the roughness values was found between systems (P = 0.07 for R_a, P = 0.33 for R_z, and P = 0.48 for R_max). There was a significant average decrease of R_a, R_z, and R_max for all systems for every unit increase in time by -0.171 μm (P < 0.001), -3.297 (P ≤ 0.001), and -2.788 μm (P = 0.001), respectively. R_a, R_z, and R_max values increased significantly, i.e., by 0.194 μm (P = 0.003), 5.890 μm (P = 0.001), and 5.319 μm (P = 0.010) as instrument thickness increased by one unit. No significant reductions in R_a, R_z, and R_max were observed across grain sizes (-0.008 μm [P > 0.05], -0.244 μm [P > 0.05], and -0.179 μm [P > 0.05], respectively). There was no evidence of interaction between system and time as the P values for R_a, R_z, and R_max were 0.88, 0.51, and 0.70, respectively.

CONCLUSIONS

All IPR materials presented significant gradual decrease of surface roughness after repeated applications. There were no significant roughness changes among auxiliaries of different grain sizes. Thinner auxiliaries showed significantly more roughness reduction, possibly requiring more frequent replacement than thick auxiliaries in clinical practice.

Enamel protection after stripping procedures: An in vivo study

INTRODUCTION

Interproximal enamel reduction (IPR) is a clinical procedure that has been in use since the advent of non-extraction orthodontic techniques. However, such a procedure affects the surface condition of the enamel and may predispose patients to cavities and hypersensitivity. The use of a remineralizing agent is recommended to prevent these side effects. The objective of our study was to evaluate the evolution of stripped proximal dental surfaces after exposure to the oral environment for 4 months with and without fluoride protection.

MATERIALS AND METHODS

Our sample consisted of 14 premolars (PM) from 6 patients of the Dentofacial Orthopaedics Department of the Consultation and Dental Treatment Centre of Rabat (CDTC) who required orthodontic treatment with PM extraction and had given their informed consent. The teeth were divided into 5 groups: group 1: intact enamel; group 2: intact enamel+fluoride varnish+4-month oral exposure; group 3: IPR (manual and mechanized)+extraction; group 4: IPR (manual and mechanized) without varnish+4-month oral exposure; group 5: IPR (manual and mechanized)+fluoride varnish+4-month oral exposure. Proximal surfaces were subjected to qualitative analysis by scanning electron microscopy and quantitative analysis by Dispersive Energy Spectroscopy (DES) to quantify the percentage of mineral elements.

RESULTS

Exposure of stripped dental surfaces to the oral environment for 4 months with or without fluoride protection showed the persistence of surface irregularities caused by stripping. We noted an improvement in the percentage of mineral elements for both groups with and without fluoride protection. However, the percentages of calcium (Ca) and phosphorus (P) were close to that of intact enamel in the fluoride varnish group.

CONCLUSION

Protecting stripped surfaces with fluoride varnish could help preserve the integrity of the enamel surface by restoring some of the mineral elements lost during stripping.

In vitro Macro-qualitative Comparison of Three Enamel Stripping Procedures: What is the Best Shape We can get?

Aim

Interdental stripping is a common clinical procedure in orthodontic therapy, by reshaping the proximal contacts. Handheld abrasive strips have been criticized as time-consuming process. Metallic strip system, diamond disk, or segment disks have become increasingly popular. The aim of this study is to evaluate the morphological aspects of remodeled dental surfaces so as to conclude which of the different techniques (disk, bur, or strip) used to reduce the mesiodistal diameter is the best to reproduce the initial contour of the proximal surface of the tooth.

Materials and methods

Seventy-nine pieces (“teeth”) were prepared from permanent healthy teeth (premolars and molars) extracted for orthodontic reasons. They were mounted on a stand resembling the position of the natural teeth in a mild crowded dentition. The “teeth” are divided into three groups as follows: group S (strip): 26 “teeth,” group D (disk): 25 “teeth,” group B (bur): 28 “teeth.” In order to study the changes, these prepared “teeth” are macro-photographed in groups of 5 before and after proximal grinding.

Results

The “teeth” contours have been identified using piecewise cubic Hermit polynomials. The change in the contour has been traduced in terms of the change of curvature in the “teeth” contours. We used the z-test in order to find the confidence interval for the proportion of the class “+” for each of the techniques B, S, and D. With confidence level of 95%, we obtained the following confidence intervals:

B = (0.6943; 0.9057); S = (0.9093; 1.0138); D = (0.6184; 0.8616)

These results can be interpreted, as the technique S is significantly much better than the other two techniques if we aim at conserving the shape of the teeth before and after treatment.

Conclusion

We conclude that the use of a strip for remodeling the proximal surface of a tooth is an optimal technique to preserve the proximal shape of the tooth although it requires more time.

Clinical significance

The use of abrasive strip preserves the best shape of the proximal side. Abrasive strip could be the last step of any proximal reshaping technique.

How to cite this article: Nassif N, Gholmieh MN, Sfeir E, Mourad A. In vitro Macro-qualitative Comparison of Three Enamel Stripping Procedures: What is the Best Shape We can get? Int J Clin Pediatr Dent 2017;10(4):358-362

Enamel defects during orthodontic treatment

Background/Aim: Orthodontic treatment has an inherent potential for causing defects to enamel in the course of bonding and debonding procedures, interproximal enamel stripping and induce the presence of white spot lesions, enamel discoloration or wear. The aim of this study is to present the stages of orthodontic therapy associated with potential damage to enamel and list the enamel alterations observed in each stage. Material and Methods: A literature search was carried out in MEDLINEPubMed database for papers published up to and including February 2015. Results: Enamel loss is induced by cleaning with abrasives before etching, the acid etching process itself, forcibly removing brackets, and mechanical removal of composite remnants with rotary instruments. Loss of enamel or topographic changes in the form of cracks, scarring and scratches may occur. Clinicians may cause structural damage of enamel by interproximal enamel stripping. Additionally, the enamel surface may become demineralized due to plaque accumulation around the orthodontic attachments. Additional complications are enamel color alterations due to its microstructural modifications or discoloration of adhesive remnants and enamel wear due to contact with the brackets of the opposing teeth. Conclusions: Therapeutic procedures performed in the course of orthodontic treatment may cause irreversible physical damage to the outermost enamel. To avoid this, the orthodontic practitioner should take great care in every stage of the treatment and manage the enamel surface conservatively. Moreover, patients should follow an effective oral hygiene regimen. Given these conditions enamel damage during orthodontic therapy is eliminated and longevity of the dentition is promoted.

Effects of casein phosphopeptide-amorphous calcium phosphate application after interproximal stripping on enamel surface: An in-vivo study

INTRODUCTION

The aim of this study was to investigate the effects of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) application after interproximal stripping on enamel surface structures in vivo.

METHODS

Fifteen patients with a mean age of 15.8 years participated in this study. For each patient, the extraction of 4 first premolars was part of the orthodontic treatment plan. The patients were randomly divided into 5 groups of 3 patients. With the exception of group 1, the mesial and distal surfaces of all first premolars were stripped with a stripping disc (Komet; Gebr Brasseler, Lemgo, Germany) under air cooling and then polished with Sof-Lex polishing discs (3M Dental Products, St Paul, Minn). In group 1, no stripping was performed, and the teeth were removed immediately. In group 2, the teeth were removed immediately after the stripping. In group 3, the stripped teeth were extracted after exposure to oral conditions for 3 months. In groups 4 and 5, CPP-ACP (Recaldent Tooth Mousse; GC Europe, Leuven, Belgium) or fluoride varnish (Bifluoride 12; Voco, Cuxhaven, Germany) was applied to the stripped surfaces for 3 months, respectively, before the teeth were extracted. Surface roughness and microhardness values were evaluated with 1-way analysis of variance and Tukey HSD tests.

RESULTS

The CPP-ACP and the fluoride varnish applications increased the surface roughness and microhardness values that had been decreased by stripping. No statistically significant differences were found between groups 3, 4, and 5 for microhardness or between groups 4 and 5 for surface roughness (P > 0.5).

CONCLUSIONS

The saliva and saliva plus remineralizing agents (fluoride varnish and CPP-ACP) increased the microhardness and surface roughness values of stripped enamel surfaces that had been decreased by stripping.

An in vitro study on the effect of an oscillating stripping method on enamel roughness

BACKGROUND

The aim of the present study was to assess the changes in enamel roughness parameters before and after stripping with an oscillating diamond strip system.

METHODS

Sound premolars extracted for orthodontic reasons were embedded up to their cervical area in a polyvinylsiloxane putty, creating four groups of four teeth with three interproximal areas each (mesial/distal). The same regions of interproximal enamel surfaces were studied by 3D optical interferometric profilometry before and after stripping with the Ortho-Strips system (Intensiv Dental SA, Montagnola, Switzerland) (n teeth = 16, n contact points = 12, n sites measured = 24). The roughness parameters tested were the amplitude parameters Sa and Sz, the hybrid parameter Sdr, and the functional parameters Sci and Svi. The parameter differences (ΔSa, ΔSz, ΔSdr, ΔSci, ΔSvi) were calculated per region and statistically analyzed by one-sample Mann-Whitney rank sum test (a = 0.05).

RESULTS

High statistically significant differences were found in ΔSa, ΔSz, and ΔSvi median values (0.453, 3.870, and 0.040 μm, respectively); a significant difference in ΔSdr median value (1.514%); and no statistically significant difference in ΔSci (0.110 median value).

CONCLUSIONS

Under the conditions of the present study, the Ortho-Strips system seems to significantly increase the amplitude parameters Sa and Sz; the hybrid parameter Sdr, associated with the developed interfacial area ratio; and the functional parameter Svi, which depicts the volume of the deepest valleys. Under the conditions of the present study, the Ortho-Strips seems to significantly increase four of five measured roughness parameters.

Interproximal reduction of teeth: differences in perspective between orthodontists and dentists

OBJECTIVE

To determine if interproximal reduction of teeth (IPR) is perceived differently by orthodontists and general dentists.

MATERIALS AND METHODS

A Web-based survey containing statements about IPR was developed and randomly distributed to orthodontists and general dentists.

RESULTS

The majority of orthodontists and general dentists strongly agreed that IPR is a minimally invasive procedure that poses little risk for the development of interproximal decay. However, general dentists were more likely to perform post-IPR polishing and to apply topical fluoride than are orthodontists (P < .0001). A greater percentage of orthodontists strongly believed that the esthetic and occlusal benefits of IPR outweigh the potential risk of tooth decay when IPR was performed (P < .0001). A greater percentage of general dentists were hesitant to perform IPR, despite research supporting that IPR has little negative effect on the health of teeth.

CONCLUSIONS

The results of this study disproved the null hypothesis that orthodontists and general dentists share similar views regarding the use of IPR during orthodontic treatment. General dentists were more conservative in their views of IPR and were less comfortable with performing IPR as a routine procedure. General dentists felt more strongly about the importance of post-IPR polishing and application of topical fluoride. Orthodontists were more likely to have researched the long-term effects of IPR on the health of teeth and therefore felt more comfortable performing IPR during orthodontic treatment.

Change in the pulp chamber temperature with different stripping techniques

Background

The aim of this study is to evaluate the change in pulp chamber temperature during the stripping technique.

Methods

Seventy-eight proximal surfaces of 39 extracted human teeth were stripped by two techniques: double-sided perforated stripping disk (PSD) and handheld stripper (HS). The teeth were divided into three groups: incisors (group 1), premolars (2), and molars (3). A J type thermocouple was inserted into the pulp chamber for temperature evaluation during the stripping procedure.

Results

Temperature rise was observed in all groups. The average temperature increase for the incisors was 2.58°C (±0.27°C) with PSD and 1.24°C (±0.3°C) with HS; for the premolars, 2.64°C (±0.29°C) with PSD and 0.96°C (±0.39°C) with HS; and for the molars, 2.48°C (±0.38°C) with PSD and 0.92°C (±0.18°C) with HS. There was significant difference (p < 0.001) in pulp temperature variation among the stripping techniques evaluated. Greater variations in the temperature were observed for the stripping technique with PSD for all groups (3.1°C in incisors and premolars, 3.2°C in molars). Stripping performed with HS had minor differences in pulp temperature (1.7°C in incisors, 1.9°C in premolars, and 1.2°C in molars) than those in PSD group. However, the temperature variation was less than the critical threshold (5.5°C) in all groups. The results for teeth group comparison showed no significant difference in the temperature variation.

Conclusions

The stripping technique with PSD produced significant increase in pulp temperature, with no differences between the types of teeth. However, it may not be clinically relevant, and both stripping techniques can be used safely.

Orthofile®: a new approach for mechanical interproximal reduction : a scanning electron microscopic enamel evaluation

PURPOSE

The aim of this in vitro study was to evaluate the stripping achieved on different teeth (incisors, canines, and premolars) by two grades of abrasive strips used for the first and tenth time. Our second aim was to test the efficacy of these strips by calculating the time necessary to perform interproximal reductions of 0.10, 0.20, and 0.30 mm.

METHODS

Four models were constructed using extracted teeth affixed in wax. The upper and lower arches were set on plaster bases and fixed in wax, carefully creating contact points. All model mouths were treated with artificial saliva (Oral Balance®) in order to simulate the biological conditions in the oral cavity. We then tested specific air-rotor strips of different grades and degrees of wear (15-µm-grain and 25-µm-grain Orthofile® strips). Afterwards the teeth from all samples were cut lengthwise in half, and each mesial and distal portion was gold-plated and observed under SEM at incremental magnification (30, 60, and 100 µm).

RESULTS

The 25-µm-grain strip was more effective than the 15-µm-grain strip, irrespective of the tooth involved. Second, the finishing phase with specific polishing strips after interproximal reduction was fundamental in reducing the number of abrasions and irregularities created by stripping, in particular after using the 25-µm-grain strip. To achieve the best result, the entire abraded area must be polished.

CONCLUSION

This system permits a rapid and effective stripping procedure in direct proportion to the strip's grain and in inverse proportion to the wear from its use. Further research will enable us to compare this system with similar procedures.

Enamel reduction techniques in orthodontics: a literature review

Artificial abrasion of interproximal surfaces has been described for almost seventy years as orthodontic intervention for achievement and maintenance of ideal treatment outcome. A variety of terms and approaches have been introduced throughout this period implying a growing clinicians’ interest. Nevertheless, the widespread recognition of enamel stripping technique was initiated by the advent of bonded orthodontic attachments and a 2-article series of Sheridan in the 80’s. Since then, experimental and clinical research has been focused on the investigation of instrumentation efficacy and potential iatrogenic sequelae related to interproximal stripping. This review discusses the evolution, technical aspects and trends of enamel reduction procedures as documented in the literature.

Comparison between different interdental stripping methods and evaluation of abrasive strips: SEM analysis

OBJECTIVES

The aim of this study was to evaluate the morphological effects and the surface irregularities produced by different methods of mechanical stripping (abrasive strips and burs) and chemical stripping (37% orthophosphoric acid) and the surface changes following the finishing procedures (polishing strips) or the subsequent application of sealants, in order to establish the right stripping method that can guarantee the smoothest surface. We have also analysed the level of wear on the different abrasive strips employed, according to their structure.

MATERIALS AND METHODS

160 proximal surfaces of 80 sound molar teeth extracted for orthodontic and periodontal reasons, were divided into: 1 control group with non-treated enamel proximal surfaces and 5 different groups according to the stripping method used, were observed with scanning electron microscopy (SEM). Each one of the 5 treated groups was also divided into 3 different subgroups according to the finishing procedures or the subsequent application of sealants.

RESULTS

The finishing stage following the manual reduction proves to be fundamental in reducing the number and depth of grooves created by the stripping. After the air rotor stripping method, the use of sealants is advised in order to obtain a smoother surface. The analysis of the combinations of mechanical and chemical stripping showed unsatisfactory results. Concerning the wear of the strips, we have highlighted a different abrasion degree for the different types of strips analysed with SEM.

CONCLUSIONS

The enamel damages are limited only if the finishing procedure is applied, independently of the type of abrasive strip employed. It would be advisable, though clinically seldom possible, the use of sealants after the air rotor stripping technique.

In vitro evaluation of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) effect on stripped enamel surfaces. A SEM investigation

OBJECTIVES

Interproximal enamel reduction (orthodontic stripping) leaves surface-roughness that encourages plaque adherence. Sealants and fluoride products have been recommended to avoid possible detrimental effects. The objective of this study was to qualitatively evaluate, by means of scanning electron microscopy (SEM), the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on stripped enamel morphology after exposure to an acid solution.

METHODS

15 extracted lower incisors underwent stripping with metal strips (Horico, 80 microm) by 1 operator. Mesial and distal surfaces were sectioned into 30 samples (22 stripped; 8 unstripped) and assigned to 2 groups: Group A (2 stripped; 2 unstripped) served as control; in Group B (20 stripped; 6 unstripped) tooth mousse containing CPP-ACP was tested. For 8 days, teeth were placed in acid lactic solution for 2h three times a day (from 9a.m. to 9p.m.) with 2h water preservation in between. After each demineralizing bath, samples of group B were coated with CPP-ACP for 5 min before immersion into water.

RESULTS

In Group A, stripped samples exhibited greater demineralization compared to unstripped. In Group B, CPP-ACP reduced enamel dissolution on both intact and abraded samples compared to Group A.

CONCLUSIONS

Injuries to enamel morphology caused by stripping might predispose to greater demineralization in the event of exposure to acid environment. Topical applications of CPP-ACP could be effective in promoting enamel remineralization after interdental stripping.

Enamel surfaces following interproximal reduction with different methods

OBJECTIVE

To assess the surface roughness resulting after application of currently available interproximal polishing.

MATERIALS AND METHODS

The analysis was carried out by means of digital subtraction radiography, profilometry, and scanning electron microscopy. The roughness of natural untreated enamel served as the reference. Five enamel reduction methods were tested (Profin, New Metal Strips, O-Drive D30, Air Rotor, and the Ortho-Strips) and were applied in accordance with their manufacturers' recommendations. Fifty-five teeth were treated by randomly chosen methods, all of which were applied by one person. One proximal surface was only ground and left unpolished while the other received the finishing and polish recommended by the manufacturer.

RESULTS

Loss of tooth substance, as measured by subtraction radiography, was significantly lower (P < .05) for the group treated with Ortho-Strips. Profilometric analysis of enamel roughness showed that the use of Ortho-Strips, O-Drive D30, and New Metal Strips in the grinding mode produced equally rough surfaces (P > .05). The Air Rotor and Profin system in the grinding mode produced the significantly (P < .05) roughest surfaces. A significant (P < .05) reduction of the mean roughness values was registered in all groups when treatment was followed by polishing. The Profin system and Ortho-Strips achieved the significantly smoothest surfaces (P < .05) with polishing.

CONCLUSIONS

In general, interproximal enamel reduction should be followed by thorough polishing. Furthermore, oscillating systems seem to be advantageous.

Temperature Rise in the Pulp Chamber duringDifferent Stripping Procedures

OBJECTIVE

To measure the temperature changes in the pulp chamber when different stripping procedures were used without any type of coolant.

MATERIALS AND METHODS

Ninety intact, freshly extracted human teeth were used in this study. The teeth were separated into nine groups of 10 teeth each. Mesial and distal sides of the teeth were used separately. The stripping procedures were performed on three different tooth groups (incisor, canine, premolar) with a metal handheld stripper, perforated stripping disk, or tungsten carbide bur. A J-type thermocouple wire was positioned in the center of the pulp chamber and was connected to a data logger during application of stripping procedures. The results were analyzed by analysis of variance (ANOVA) and the Duncan test.

RESULTS

Two-factor ANOVA revealed significant interaction between the stripping procedure and the tooth type (P = .000). The results of this study demonstrate that tungsten carbide burs used on mandibular incisors had the highest temperature variation (DeltaT) values, which exceeded the critical level (5.5 degrees C), and this was significantly higher than those of the other stripping procedures (DeltaT: 5.63 +/- 1.73 degrees C). On the other hand, six of the nine groups also produced temperature increases above the critical level (5.5 degrees C) for some of the specimens.

CONCLUSIONS

Frictional heat is a common side effect of stripping procedures, and appropriate measures (ie, cooling application) should be taken particularly for high-speed hand-piece stripping of mandibular incisors.

Dental health assessed more than 10 years after interproximal enamel reduction of mandibular anterior teeth

INTRODUCTION

We investigated whether interdental enamel reduction using fine diamond disks with air cooling, followed by polishing, leads to iatrogenic damage or reduced interradicular distances.

METHODS

Our subjects were 61 consecutive patients who had received mesiodistal enamel reduction of all 6 mandibular anterior teeth more than 10 years previously. Dental caries, bleeding on probing, probing depths, and gingival recessions were assessed with standard techniques. Incisor irregularities and tooth width/thickness ratios were measured on models, and the patients were asked about any increased tooth sensitivity. The reference group comprised 16 students.

RESULTS

No new caries lesions were detected. Three mature adults had some minor labial gingival recessions. There was no evidence of root pathology. The distance between the roots of the mandibular incisors was statistically significantly greater in the patients who had received stripping than in those who had not; 59 of 61 patients reported no increased sensitivity to temperature variations. The overall irregularity index at follow-up was only 0.67 (SD, 0.64).

CONCLUSIONS

Interdental enamel reduction according to this protocol did not result in iatrogenic damage. Dental caries, gingival problems, or alveolar bone loss did not increase, and the distances between the roots of the teeth in the mandibular anterior region were not reduced. The overall incisor irregularity at the follow-up examination was small.

Interdisciplinary treatment of an adult patient with old extraction sites

This case report describes the interdisciplinary treatment of a 31-year-old female patient showing a protrusive profile, maxillary constriction, mandibular crowding, a Class III canine relationship complicated with multiple missing teeth, old atrophic extraction sites, and periodontal defects. The lower dental arch irregularity was eliminated by air-rotor stripping (ARS). The upper extraction site was opened for prosthetic rehabilitation, whereas closure of the lower extraction space was preferred. The narrow alveolar crest of the atrophic bone was augmented with the use of autogenous bone, beta-tricalcium phosphate (Cerasorb), and autogenous platelet-rich plasma. A functional and esthetic occlusion in an improved facial profile was established at the end of orthodontic treatment combined with ARS technique, surgery, and prosthodontics.

Qualitative and quantitative evaluation of enamel after various stripping methods

INTRODUCTION

In this study, we investigated ultramorphology, surface roughness, and microhardness of permanent and deciduous tooth enamel after various stripping methods.

METHODS

One hundred twenty deciduous and permanent teeth (n = 60 each) were used. Qualitative (scanning electron microscopy) and quantitative (surface roughness and microhardness tests) experiments were carried out in the following experimental groups: group 1, stripping disk; group 2, diamond-coated metal strip; group 3, stripping disk and Sof-Lex discs (3M-ESPE, Seefeld, Germany); group 4, diamond-coated metal strip and Sof-Lex discs; group 5 (chemical stripping), 37% orthophosphoric acid in conjunction with diamond-coated metal strip; group 6 (control), no stripping. Surface roughness values (Ra) for permanent and deciduous enamel were evaluated with Welch analysis of variance (ANOVA) and Tamhane tests, and Kruskal-Wallis and Mann-Whitney tests, respectively. Microhardness values were evaluated statistically with Kruskal-Wallis, 1-way ANOVA, and Duncan tests.

RESULTS

Deciduous and permanent teeth showed similar results in terms of surface roughness and surface morphology. Groups 3 and 4 had the smoothest deciduous and permanent enamel surfaces, whereas chemical stripping (group 5) produced the roughest surfaces in both enamel types. Stripping did not lead to a significant change in the microhardness of permanent enamel.

CONCLUSIONS

All stripping methods significantly roughened the enamel surfaces. Polishing the stripped surface with Sof-Lex discs decreased the roughness.

Caries risk after interproximal enamel reduction

INTRODUCTION

Air-rotor stripping (ARS) is a commonly used method to alleviate crowding in the permanent dentition. Its widespread acceptance, however, has been limited by the potential increase in caries risk of the abraded enamel surface. The aim of this study was to compare the susceptibility of ARS-treated enamel surfaces with intact surfaces in patients undergoing fixed orthodontic therapy.

METHODS

Forty patients treated with ARS were examined clinically and radiographically for caries 1 to 6 years after interproximal enamel reduction. All patients were seen by their dentists for prophylaxis at 6-month intervals during active orthodontic treatment and were exposed to fluoridated water and toothpaste. Topical fluoride agents or sealants were not applied on the abraded surface after any ARS session. Caries incidence was compared between ARS-treated and unaltered surfaces within subjects. The decayed, missing, filled tooth (DMFT) and surface (DMFS) scores were used to evaluate the subjects' overall caries risk.

RESULTS

Totals of 376 test and 376 control surfaces were examined. The number of interproximal lesions detected was found to be low with no statistically significant difference detected between the groups (test = 3; control = 6; P = .33]. The DMFT and DMFS scores increased significantly during the study period, indicating that these patients were clearly at risk of tooth decay (P <.001).

CONCLUSIONS

The findings indicate that the risk of caries is not affected by ARS. Furthermore, our data show that the application of topical fluoride on the enamel surfaces immediately after ARS in patients exposed to fluoridated water and fluoride-containing toothpaste may not provide any additional benefit.

A scanning electron microscopy comparison of enamel polishing methods after air-rotor stripping

In the last few years, orthodontic literature has shown particular interest in the interproximal enamel reduction technique described as stripping or slenderizing. Most researchers have shown, by scanning electron microscopy (SEM) studies, the difficulties encountered while attempting to remove coarse abrasions left after stripping with the first instrument. The objective of this SEM study was to compare the different polishing methods proposed in the literature and to assess the efficiency of our own procedure. For this purpose, 48 healthy human teeth (premolars and molars) were used after removal for orthodontic or periodontal reasons. The teeth were divided into eight groups of six teeth each (two molars and four premolars), and mounted on a typodont to simulate a clinical situation. Each group underwent stripping according to one of the following techniques: 16-blade tungsten carbide bur and fine and ultrafine diamond burs; coarse diamond bur and fine and ultrafine diamond burs; coarse diamond disk and Sof-Lex disks (Dental products/3M, St. Paul, Minn.); 16-blade tungsten carbide bur and phosphoric acid on finishing strip; and 8-straight blade tungsten carbide diamond bur and Sof-Lex disks. The SEM investigations demonstrated that it is not possible to eliminate, with normal polishing and cleaning methods, the furrows left on the enamel both by the diamond burs and the diamond disks and the 16-blade tungsten carbide burs. Mechanical and chemical stripping as well did not prove to be effective. By contrast, with the use of a 8-straight blade tungsten carbide bur followed by Sof-Lex disks for polishing the enamel, it is possible to obtain well-polished surfaces that many times appear smoother than the intact or untreated enamel.