- Email: [email protected]
Bulk fill composites versus incrementally placed hybrids
be considerably more invasive. Composite restorations have fewer maintenance requirements as well. Patients also report a higher quality of life after placement of composite restorations to manage tooth wear.
Clinical Significance.—Further research is required, but there is evidence to support the use of composite resin restorations to manage tooth wear. Ninety-one percent of patients achieved increased OVD within 18 months. Long-term survival remains unknown,
however, so more studies are needed to address this aspect.
Ahmed KE, Murbay S: Survival rates of anterior composites in managing tooth wear: Systematic review. J Oral Rehabil 43:145-153, 2016 Reprints available from KE Ahmed, Comprehensive Dental Care Dept, Prince Philip Dental Hosp, Faculty of Dentistry, 34 Hospital Rd, Univ of Hong Kong, Hong Kong (SAR), China; e-mail: [email protected]
Bulk fill composites versus incrementally placed hybrids Background.—The current composite filling materials offer improved esthetics, avoid the risks of dental amalgam, and allow cavity preparation to be more conservative and protective of the remaining tooth structure. The most recent formulations also address the problems of polymerization shrinkage, with the newest posterior resin composite restorations (PRCRs) largely avoiding postoperative sensitivity and discomfort after placement. Bulk fill composite systems and incrementally placed hybrid PRCRs were compared in terms of postoperative sensitivity and tenderness on biting. Methods.—Two treatment groups were formed from carious teeth in 72 subjects, with group A restored using a bulk dentin replacement material and group B restored using incrementally placed hybrid composite. Follow-up via structured phone call was done 2 and 7 days after restoration. Patients who reported discomfort after 7 days were further followed up at days 14 and 30. Results.—Seventeen Class I cavities were restored (8 in group A and 9 in group B). Fifty-five Class II cavities were restored (28 in group A and 27 in group B). Only 3% of the cavities demonstrated sensitivity after 30 days, and none of the teeth had tenderness to biting then. After 2 days, 18 of the teeth had postoperative sensitivity. Patients in group A had a higher level of postoperative sensitivity than those in group B. After 7 days, 8 teeth had postoperative sensitivity, with no statistically significant difference between the two groups.
After 2 days, 8 teeth had tenderness to biting and after 7 days, 6 teeth demonstrated tenderness. Subjects with Class I cavities reported greater tenderness on biting than those with Class II cavities. Five of the Class I cavities (30%) and 13 of the Class II cavities (23%) demonstrated postoperative sensitivity after restoration placement. The differences between the rates of postoperative sensitivity were not statistically significant between the two groups at day 2 or 7. Two restorations (24%) in Class I cavities and 2 (7%) in Class II cavities had tenderness on biting. The difference was statistically significant regardless of the technique used. Discussion.—The postoperative sensitivity was slightly greater in group A teeth than group B teeth after 2 days. Tenderness on biting, however, did not differ significantly between the two groups. More well-designed studies carried out in clinical settings are needed to help determine the clinical effectiveness and longevity of the newest composite filling materials.
Clinical Significance.—Both bulk fill composites and incrementally placed hybrid PRCRs can produce postoperative problems with sensitivity and discomfort after placement. Both types of difficulties are short-lived, however. Because the time required for bulk placement
Volume 61
Issue 5
2016
251
of restorations is short, this approach is an acceptable alternative to incremental build-up of composites for short-term and mid-term restorations. Long-term studies are needed to support extended use.
Hickey D, Sharif O, Janjua F, et al: Bulk dentine replacement versus incrementally placed resin composite: A randomized controlled clinical trial. J Dent 46:18-22, 2016 Reprints available from PA Brunton, 310 Great King St, PO Box 647, Dunedin, New Zealand; e-mail: [email protected]
Dental Implants Tapered implant essentials Background.—Specific factors contribute to the success and durability of dental implants. The four main factors that create stability in implants are implant design, surface, surgical technique, and bone quality of the recipient site. The way these factors relate to one another defines the initial stability and influences the lifespan of these interventions. Parameters that can influence the success of tapered implants, which have been shown to be the most successful design, include drill protocol, thread design, surface modification, and implant shape. Drilling Protocol.—Low levels of compressive stresses after the implant is placed and micromotion is reduced are facilitated by proper implant selection and surgical drilling technique. The relationship between implant shape and bone also must be considered. High insertion torque may reduce destructive micromotion but does not always lead to stability. Surgical instrumentation and implant design may produce high levels of contact between implant and bone directly after placement, which will reduce micromovement. Contact of the implant thread outer portions may attain primary stability of the implant and permit the formation of void spaces between the implant and bone just after placement. Eliminating bone resorption in these chambers permits healing and faster bone formation. This minimizes implant stability loss where compression occurs and may permit immediate or early functional loading of single implants in poor quality bone. Surface texture and chemistry changes alter the bonehealing kinetics at the thread region early in the healing process. Use of an undersized drilling technique optimizes bone density and improves primary implant stability. In addition, the use of a tapered drill with a tapered implant may create more stability than the use of a straight drill with a tapered implant. Recently a cylindo-conical tapered implant was developed to create a drilling sequence that
252
Dental Abstracts
accounts for bone density (Fig 1). The shorter pitch of this device may be especially useful for areas of poor bone quality because it may increase the surface area and create higher levels of bone-implant contact (BIC). Thread Design.—The biomechanical design of implants can be optimized to improve implant osseointegration. This principle applies to all types of implant designs. Thread shape is determined by thread thickness and thread face angle and includes V-shaped, square shape, buttress, and reverse buttress types. Thread shape defines the angle between a thread face and a pleat threading perpendicular to the implant’s long axis. Thread pitch refers to the distance between thread centers as measured parallel to the screw axis. Pitch can significantly affect implant design because it influences surface area. As pitch decreases, surface area increases and the distribution of stress is more favorable for success. Stresses are more sensitive to thread pitch in cancellous than in cortical bone. Thread depth is the distance from the tip of the thread to implant body, whereas thread width is the distance in the same axial plane between the coronal-most and the apicalmost part at the tip of a single thread. Implant threads should provide favorable stress profiles and minimize adverse stress on the bone interface. The ideal implant scheme balances compressive and tensile forces while minimizing shear force generation. For implant stability the most favorable configuration is a single-threaded design, followed by a doublethreaded one. Microthread theory in the crestal portion has been considered to maintain marginal bone and soft tissues around the implants. In addition, it has been proposed that using a retaining plant neck will dissipate forces at the implant neck and sustain crestal bone height. The concept of preserving crestal bone is controversial, however. The highest stress concentrations occur around
Clinical Significance.—Further research is required, but there is evidence to support the use of composite resin restorations to manage tooth wear. Ninety-one percent of patients achieved increased OVD within 18 months. Long-term survival remains unknown,
however, so more studies are needed to address this aspect.
Ahmed KE, Murbay S: Survival rates of anterior composites in managing tooth wear: Systematic review. J Oral Rehabil 43:145-153, 2016 Reprints available from KE Ahmed, Comprehensive Dental Care Dept, Prince Philip Dental Hosp, Faculty of Dentistry, 34 Hospital Rd, Univ of Hong Kong, Hong Kong (SAR), China; e-mail: [email protected]
Bulk fill composites versus incrementally placed hybrids Background.—The current composite filling materials offer improved esthetics, avoid the risks of dental amalgam, and allow cavity preparation to be more conservative and protective of the remaining tooth structure. The most recent formulations also address the problems of polymerization shrinkage, with the newest posterior resin composite restorations (PRCRs) largely avoiding postoperative sensitivity and discomfort after placement. Bulk fill composite systems and incrementally placed hybrid PRCRs were compared in terms of postoperative sensitivity and tenderness on biting. Methods.—Two treatment groups were formed from carious teeth in 72 subjects, with group A restored using a bulk dentin replacement material and group B restored using incrementally placed hybrid composite. Follow-up via structured phone call was done 2 and 7 days after restoration. Patients who reported discomfort after 7 days were further followed up at days 14 and 30. Results.—Seventeen Class I cavities were restored (8 in group A and 9 in group B). Fifty-five Class II cavities were restored (28 in group A and 27 in group B). Only 3% of the cavities demonstrated sensitivity after 30 days, and none of the teeth had tenderness to biting then. After 2 days, 18 of the teeth had postoperative sensitivity. Patients in group A had a higher level of postoperative sensitivity than those in group B. After 7 days, 8 teeth had postoperative sensitivity, with no statistically significant difference between the two groups.
After 2 days, 8 teeth had tenderness to biting and after 7 days, 6 teeth demonstrated tenderness. Subjects with Class I cavities reported greater tenderness on biting than those with Class II cavities. Five of the Class I cavities (30%) and 13 of the Class II cavities (23%) demonstrated postoperative sensitivity after restoration placement. The differences between the rates of postoperative sensitivity were not statistically significant between the two groups at day 2 or 7. Two restorations (24%) in Class I cavities and 2 (7%) in Class II cavities had tenderness on biting. The difference was statistically significant regardless of the technique used. Discussion.—The postoperative sensitivity was slightly greater in group A teeth than group B teeth after 2 days. Tenderness on biting, however, did not differ significantly between the two groups. More well-designed studies carried out in clinical settings are needed to help determine the clinical effectiveness and longevity of the newest composite filling materials.
Clinical Significance.—Both bulk fill composites and incrementally placed hybrid PRCRs can produce postoperative problems with sensitivity and discomfort after placement. Both types of difficulties are short-lived, however. Because the time required for bulk placement
Volume 61
Issue 5
2016
251
of restorations is short, this approach is an acceptable alternative to incremental build-up of composites for short-term and mid-term restorations. Long-term studies are needed to support extended use.
Hickey D, Sharif O, Janjua F, et al: Bulk dentine replacement versus incrementally placed resin composite: A randomized controlled clinical trial. J Dent 46:18-22, 2016 Reprints available from PA Brunton, 310 Great King St, PO Box 647, Dunedin, New Zealand; e-mail: [email protected]
Dental Implants Tapered implant essentials Background.—Specific factors contribute to the success and durability of dental implants. The four main factors that create stability in implants are implant design, surface, surgical technique, and bone quality of the recipient site. The way these factors relate to one another defines the initial stability and influences the lifespan of these interventions. Parameters that can influence the success of tapered implants, which have been shown to be the most successful design, include drill protocol, thread design, surface modification, and implant shape. Drilling Protocol.—Low levels of compressive stresses after the implant is placed and micromotion is reduced are facilitated by proper implant selection and surgical drilling technique. The relationship between implant shape and bone also must be considered. High insertion torque may reduce destructive micromotion but does not always lead to stability. Surgical instrumentation and implant design may produce high levels of contact between implant and bone directly after placement, which will reduce micromovement. Contact of the implant thread outer portions may attain primary stability of the implant and permit the formation of void spaces between the implant and bone just after placement. Eliminating bone resorption in these chambers permits healing and faster bone formation. This minimizes implant stability loss where compression occurs and may permit immediate or early functional loading of single implants in poor quality bone. Surface texture and chemistry changes alter the bonehealing kinetics at the thread region early in the healing process. Use of an undersized drilling technique optimizes bone density and improves primary implant stability. In addition, the use of a tapered drill with a tapered implant may create more stability than the use of a straight drill with a tapered implant. Recently a cylindo-conical tapered implant was developed to create a drilling sequence that
252
Dental Abstracts
accounts for bone density (Fig 1). The shorter pitch of this device may be especially useful for areas of poor bone quality because it may increase the surface area and create higher levels of bone-implant contact (BIC). Thread Design.—The biomechanical design of implants can be optimized to improve implant osseointegration. This principle applies to all types of implant designs. Thread shape is determined by thread thickness and thread face angle and includes V-shaped, square shape, buttress, and reverse buttress types. Thread shape defines the angle between a thread face and a pleat threading perpendicular to the implant’s long axis. Thread pitch refers to the distance between thread centers as measured parallel to the screw axis. Pitch can significantly affect implant design because it influences surface area. As pitch decreases, surface area increases and the distribution of stress is more favorable for success. Stresses are more sensitive to thread pitch in cancellous than in cortical bone. Thread depth is the distance from the tip of the thread to implant body, whereas thread width is the distance in the same axial plane between the coronal-most and the apicalmost part at the tip of a single thread. Implant threads should provide favorable stress profiles and minimize adverse stress on the bone interface. The ideal implant scheme balances compressive and tensile forces while minimizing shear force generation. For implant stability the most favorable configuration is a single-threaded design, followed by a doublethreaded one. Microthread theory in the crestal portion has been considered to maintain marginal bone and soft tissues around the implants. In addition, it has been proposed that using a retaining plant neck will dissipate forces at the implant neck and sustain crestal bone height. The concept of preserving crestal bone is controversial, however. The highest stress concentrations occur around