In Focus: Monthly study highlights

1. Performance of a new implant system and drilling protocol-A minipig intraoral dental implant model study.

Musskopf ML, Finger Stadler A, Fiorini T, et al. Clin Oral Implants Res. 2023 Oct 19.

In this animal intraoral dental implant model, a team of scientists from the US and Brazil led by Prof. Susin from the University of North Carolina looked into the safety and efficacy of the Nobel Biocare N1™ system and compared the rate of osseointegration with the well-established and clinically proven NobelActive implant. They observed:

– Enhanced osseointegration of the N1 implants, based on the percentage of BIC measured along the entire length of the implant within the extension of resident bone, which was 74.1% for N1 vs 60.9% in the control group after 13 weeks (p <0.001). Significantly higher BIC and trabecular thickness with N1 were also confirmed with the microCT analysis.

– Comparable mucosa height, epithelium length, and epithelium-platform distance between groups were reported. – Close contact of soft tissue and abutment or healing cap sealed the gap between the implant and bone around the platform.

– Similar insertion torque of the N1 Implant and NobelActive® groups were reached.

The authors concluded, “The site preparation protocol of the N1 implant system, which includes the use of drilling tools at low speed with no irrigation, simplifies implant site preparation and seems to favor peri-implant bone healing.”

Read the full study in the open-access journal.

2. Orthodontic tooth extrusion to regenerate missing papilla adjacent to maxillary anterior single implants: A 2- to 7-year retrospective study.

Kan JYK, Rungcharassaeng K, Yin S, Kang P, et al. J Esthet Restor Dent. 2023 Oct 13.

This retrospective study from Prof. Kan and colleagues throughout the US with 14 patients evaluated the use of orthodontic extrusion to regenerate dento-implant papilla defect. Of 14 implants, 12 were selected from the Nobel Biocare portfolio, and the other 2 were from Straumann and Dentsply Sirona. The implant success rate was 100% after a 4-year follow-up.

 – After a mean extrusion and retention period of 14.3 months, a mean orthodontic extrusion movement of 4.62 ± 0.78 mm was noted with a mean proximal bone level gain of 3.54 ± 0.61 mm (77.0% efficacy).

– Dento-implant papilla level gain of 3.98 ± 0.81 mm (86.8% efficacy), and facial gingival tissue gain of 4.27 mm ± 0.55 mm (93.4% efficacy) were reported.

– A mean keratinized tissue width gain of 4.17 ± 0.49 mm with minimal mean mucogingival junction level change of 0.10 ± 0.30 mm was observed.

Check out the clinical case in the open access manuscript, Figures 6-18, showing a step-by-step treatment protocol. After discussing various treatment options with the patient, the patient decided to have an immediate implant placement and provisionalization procedure made possible through NobelActive implant design.

3. Effects of cyclic loading on loss of abutment screw torque of angled screw channel single implant crowns on narrow diameter implants.

Bhumpattarachai S, Kan JYK, Goodacre CJ, et al. J Prosthet Dent. 2023 7:S0022-3913(23)00507-3.

This in vitro study by Prof. Bhumpattarachai and colleagues from California compares the loss of abutment screw torque after thermocycling and the cyclic loading of angulated screw channels (ASCs) from three different companies connected to narrow-diameter implants. A total of 40 narrow-diameter NobelReplace® Conical Connection 3.5×11.5 mm were mounted in acrylic resin blocks, divided into four groups, and restored with:

1. Screw-retained zirconia crowns fabricated on Nobel Biocare angulated screw channel (ASC) at 0°
2. Screw-retained zirconia crowns fabricated on Nobel Biocare ASCs at 25°
3. 20° Atlantis Custom Base Solution with angulated screw access from Dentsply Sirona
4. 20° Dynamic TiBase® from Dynamic Abutment Solutions

The corresponding titanium base insert and screw were tightened to the manufacturer's recommended torque with a digital torque gauge. After each specimen underwent thermocycling and then cyclic loading at 0 to 100 N at 10 Hz for 1 million cycles to simulate one year of functional loading, the percentage screw torque loss among all groups after cyclic loading was significantly different (P<.001).

– The percentage of torque loss in the Atlantis Custom Base Solution group was 51.4%, and significantly higher than Nobel Biocare ASCs with 0° or 25° (22.2% and 29.2%, P=.010).

– No significant difference was found in the percentage of torque loss among other groups (P>0.05). The NB-25 group demonstrated the lowest percentage torque loss. Torgue loss in Dynamic TiBase was 44.9%.

This study suggests crowns with an angled screw channel on a narrow-diameter implant with original components may perform better than those with non-original components. A high percentage of abutment screw torque loss was observed with non-original parts, which may increase the need for periodic recall of the restoration to check for loosening.

Check out the full manuscript in PubMed.