The tunnel restoration

Equivalence study of the resin-dentine interface of internal tunnel restorations when using an enamel infiltrant resin with ethanol-wet dentine bonding

This preregistered ex vivo investigation examined the dentinal hybrid layer formation of a resinous infiltrant (Icon), with reference to both thickness (HLT) and homogeneity when combined with modified tunnel preparation (occlusal cavity only) and internal/external caries infiltration. The adhesives Syntac and Scotchbond MP were used as controls (Groups 1 and 3) or in combination with Icon (Groups 2 and 4). A split-tooth design using healthy third molars from 20 donors resulted in 20 prepared dentine cavities per experimental group. The cavity surfaces (n = 80) were etched (37% H3PO4), rinsed, and air-dried. Rewetting with ethanol was followed by application of the respective primers. After labeling with fluorescent dyes, either Syntac Adhesive/Heliobond or Scotchbond MP Adhesive was used alone or supplemented with Icon. HLT, as evaluated by scanning electron microscopy, did not significantly differ (P > 0.05), and confocal laser scanning microscopy revealed homogeneously mixed/polymerized resin-dentine interdiffusion zones in all groups. Icon can be successfully integrated into an ethanol-wet dentine bonding strategy, and will result in compact and homogeneous hybrid layers of comparable thickness considered equivalent to the non-Icon controls, thus allowing for preservation of the tooth's marginal ridge and interdental space in the case of internal/external infiltration of proximal caries.

Tunnel Restoration: A Minimally Invasive Dentistry Practice

With advances in technology, dentists nowadays manage dental caries with the philosophy of minimally invasive dentistry. Dental restoration is now performed most conservatively with minimal destruction of tooth structure when operative dentistry is indicated. Some operative dentists suggested using tunnel restoration for treating proximal caries as a conservative alternative to the conventional box preparation. The main advantage of tunnel restoration over the conventional box or slot preparation includes being more conservative and increasing tooth integrity and strength by preserving the marginal ridge. However, tunnel restoration is technique sensitive and requires advanced operative skills. Tunnel restoration can be an option to restore proximal caries if the dentist selects the proper case and pays attention to the details of the restorative procedures. With the dentist's advanced training, advanced light-emitting diode handpieces, magnifying loupes, precise digital imaging and new generation restorative materials, good results can be obtained in selected cases. This study reviews the literature on tunnel restoration and provides updated techniques and clinical data that can be used in tunnel restoration to oversee its limitations and the perspective on restorative treatment.

Class II resin composite restorations-tunnel vs. box-only in vitro and in vivo

Purpose

In a combined in vitro/in vivo approach, tunnel vs. box-only resin composite restorations should be evaluated using thermomechanical loading (TML) in vitro and a restrospective clinical trial in vivo.

Materials and methods

For the in vitro part, box-only and tunnel cavities were prepared in 32 extracted human third molars under simulated intraoral conditions in a phantom head. Specimens were randomly assigned to four groups (n = 8; 16 box-only/16 tunnel) and received bonded resin composite restorations with Amelogen Plus (box A/tunnel A) or lining with Ultraseal and Amelogen plus (box B/tunnel B) both bonded using PQ1 (all Ultradent). Specimens were subjected to a standardized aging protocol, 1-year water storage (WS) followed by TML (100,000 × 50 N; 2500 × + 5/+ 55 °C). Initially and after aging, marginal qualities were evaluated using replicas at × 200 magnification (SEM). For the corresponding in vivo observational study, 229 patients received 673 proximal resin composite restorations. From 371 tunnel restorations, 205 cavities were filled without flowable lining (tunnel A), and 166 tunnels were restored using UltraSeal as lining (tunnel B). A total of 302 teeth received conventional box-only fillings. Restorations were examined according to modified USPHS criteria during routine recalls up to 5 years of clinical service.

Results

In vitro, all initial results showed 100% gap-free margins when a flowable lining was used. Tunnels without lining exhibited some proximal shortcomings already before TML and even more pronounced after TML (p < 0.05). After TML, percentages of gap-free margins dropped to 87–90% in enamel with lining and 70–79% without lining (p < 0.05). In vivo, annual failure rates for box-only were 2.2%, for tunnel A 6.1%, and for tunnel B 1.8%, respectively (p < 0.05). Tunnels had significantly more sufficient proximal contact points than box-only restorations (p < 0.05). Flowable lining was highly beneficial for clinical outcome of tunnel-restorations (p < 0.05).

Conclusions

With a flowable lining, tunnel restorations proved to be a good alternative to box-only resin composite restorations.

Clinical relevance

Class II tunnel restorations showed to be a viable alternative for box-only restorations, however, only when flowable resin composite was used as adaptation promotor for areas being difficult to access.

Restorative Treatment Decisions on Approximal Caries Among Practicing Dentists in the College of Dentistry Clinics, Ajman University, United Arab Emirates

Objectives:

To assess restorative treatment decisions on approximal caries by dental practitioners in College of Dentistry at Ajman University regarding treatment threshold, restorative techniques and restorative materials, and to evaluate the characteristics of dentists relative to their treatment decisions.

Materials and Methods:

Questionnaires were completed by a population of 180 dentists working in the university’s clinics. The questionnaire assessed responses to the treatment threshold for a hypothetical approximal carious lesion, the most preferred types of cavity preparation and restorative materials.

Results:

Out of the 180 participants, 57.9% were females, and 42.2% were males. Eighty-three percent were 35 years old or less, 12.2% were between 36 and 50 years, and 4.4% were 50 years or older. Most participants were UAE graduates (84.4%). Majority of the participants would delay surgical intervention of the approximal carious lesion until it reaches the dentine-enamel junction (41%), and 27% would wait further until it reaches into the outer dentine, while only 21% would intervene when the lesion is limited to enamel. The majority of the participants preferred simple box preparation (72.8%), and most of them chose composite as the restorative material (85%).

Conclusion:

There is some variation among restorative treatment decisions of approximal caries by Ajman University’s dentists, but the majority tend to delay restorative intervention until caries reaches dentine, they prefer minimally invasive restorative techniques, and prefer composite as a restorative material.

A survey of practices of tunnel preparation among dentists who attended the 100th FDI Annual World Dental Congress

AIM

To study the practice of tunnel restoration (TR) among dentists who attended the 100th World Dental Federation (FDI) Annual World Dental Congress (AWDC).

METHODS

An anonymous questionnaire was administered to a sample of 150 dentists who attended the 100th FDI AWDC in 2012. The participants were asked about TR and their practice of TR. They were also asked to provide their years of dental practice and the countries in which they received their dental training.

RESULTS

Fifteen respondents were not performing restoration, and they were excluded from analysis. Most respondents (123/135) practiced general dentistry. Their basic dental training was from 46 countries and regions. Most of them (n = 117, 87%) knew about TR, and 53% (n = 71) practiced it. There were 12 dentists (9%) who had performed more than 10 TRs in the previous 12 months. Practice of TR among dentists who graduated more than 10 years previously was more common (odds ratio 5.87-5.98) than those who graduated <3 years previously.

CONCLUSIONS

The current study found that about half of the surveyed dentists practiced TR, although most of them knew about it. Tunnel restoration was performed more frequently among dentists who had more than 10 years of clinical experience.

Restoring proximal caries lesions conservatively with tunnel restorations

The tunnel restoration has been suggested as a conservative alternative to the conventional box preparation for treating proximal caries. The main advantage of tunnel restoration over the conventional box or slot preparation includes being more conservative and increasing tooth integrity and strength by preserving the marginal ridge. However, tunnel restoration is technique-sensitive and can be particularly challenging for inexperienced restorative dentists. Recent advances in technology, such as the contemporary design of dental handpieces with advanced light-emitting diode (LED) and handheld comfort, offer operative dentists better vision, illumination, and maneuverability. The use of magnifying loupes also enhances the visibility of the preparation. The advent of digital radiographic imaging has improved dental imaging and reduced radiation. The new generation of restorative materials has improved mechanical properties. Tunnel restoration can be an option to restore proximal caries if the dentist performs proper case selection and pays attention to the details of the restorative procedures. This paper describes the clinical technique of tunnel restoration and reviews the studies of tunnel restorations.

Resin composite contours

When placing posterior composite resin restorations, clinicians often struggle to achieve good contacts. Frequently contacts that are successful are only confined to the occlusal aspect of the proximal wall. A clinical technique is discussed which achieves the correct contour as well as tight contacts. The technique is also minimally invasive and highly aesthetic.

Clinical Evaluation of the Soft-Start (Pulse-delay) Polymerization Technique in Class I and II Composite Restorations

Class I and II composite restorations placed with a Soft-Start technique showed no significant changes in post-op sensitivity to cold or any decreased signs of marginal stress.