Guide · Implant prosthetics
Emergence profile and peri-implantitis: restoration design
How implant restoration design weighs on peri-implantitis (emergence angle, convex profile, hygiene access, cement) and what to ask the lab for on the order.
Short answer
Implant restoration design weighs on peri-implantitis risk: an emergence angle over 30° with a convex profile on bone-level implants, and restorations that block hygiene access, were linked to more disease in cross-sectional studies and in the 2021 EAO consensus. The contour that helps is straight or concave and lets an interdental brush through.
Step by step
- 01
Measure the emergence angle on a periapical
On a periapical radiograph, draw a line parallel to the long axis of the implant and a tangent to the restoration profile, mesially and distally. Record the angle and whether the profile is concave, straight or convex.
- 02
Probe without the restoration when it's screw-retained
Remove the screw-retained crown or bridge and probe again, recording bleeding and suppuration. With the restoration out, the probe goes deeper and the diagnosis is more accurate.
- 03
Look for cement around cemented crowns
On a cemented crown with a submucosal margin, look for residual cement all the way around, including the buccal and lingual sides, which a periapical shows poorly.
- 04
Test hygiene access
Pass an interdental brush next to the abutment, from buccal and lingual. On a splinted bridge, pay close attention to the middle implant, joined to both neighbors.
- 05
Decide what changes in the restoration
If the contour is overextended or blocks access, plan the new restoration alongside treatment: straight or concave profile, an angle of 30° or less on bone-level implants, and a taller abutment when implant depth allows.
- 06
Send the lab the reference and the order
Scan with a scan body and scan the current restoration. Give the brand, platform, whether the implant is bone- or tissue-level and its depth below the mucosa, and write down the profile you want.
Which restoration designs raise the risk of peri-implantitis?
The design most often linked to peri-implantitis is overcontouring: an emergence angle over 30° with a convex profile on bone-level implants, and a restoration the patient can’t clean around. Group 3 of the 6th EAO Consensus Conference (Clinical Oral Implants Research, 2021) concluded that overcontouring and restricted hygiene access increase the risk.
The benchmark numbers come from Katafuchi and colleagues (Journal of Clinical Periodontology, 2018), with 168 implants followed for about 11 years. On bone-level implants, peri-implantitis reached 31.3% with angles over 30°, against 15.1% at 30° or less, and 37.8% when the wide angle came with a convex profile. On tissue-level implants, no such link appeared.
Yi and colleagues (Journal of Clinical Periodontology, 2020) reproduced the finding in 349 implants and added another: a middle implant splinted to both neighbors had more peri-implantitis. Raabe and colleagues (Clinical Oral Implants Research, 2026) assessed 332 single implants after 11.2 years on average. Angles over 30° on bone-level and over 48° on tissue-level implants went with peri-implant disease.
These are cross-sectional and retrospective studies: they show association, not cause. The systematic review by Soulami, Slot and van der Weijden (Clinical and Experimental Dental Research, 2022) found only three eligible studies and urges caution.
How do you measure the emergence angle?
The emergence angle is measured on a periapical radiograph, between a line parallel to the long axis of the implant and a tangent to the restoration profile, mesially and distally. That’s how all three studies pooled by Soulami and colleagues (2022) did it, classifying the profile as straight, concave or convex.
The 30° threshold applies to bone-level implants. On tissue-level implants, Katafuchi found no link and Raabe saw one above 48°. That’s why the implant type goes on the order: the threshold changes with it.
What other restoration details affect the risk?
Residual cement, abutment height and splinting matter too. Staubli and colleagues reviewed 1,010 cemented implant restorations (Clinical Oral Implants Research, 2017). Excess cement came out as a possible risk indicator, seen more often when the tissue had healed for less than four weeks. The authors recommend a margin at the mucosal level, with access to clean off the cement.
The AO/AAP systematic review by Lin and colleagues (Journal of Periodontology, 2025) pooled 93 studies. Abutments of 2 mm or taller and non-splinted implants had less marginal bone loss; screw- and cement-retained restorations didn’t differ. Angles under 30° and a straight or concave profile went with less peri-implantitis, with two studies behind each finding.
Which signs point to the cause, and what do you do?
The causes below come from studies on restoration contour, access and retention. Each row gives what you see on exam and what changes in the restoration; the decision to treat and to remake is yours.
| cause | sign | what to do | source |
|---|---|---|---|
| Angle over 30° with convex profile, bone-level | bleeding, pocketing and bone loss under a bulky crown | remake with a straight or concave profile at 30° or less | Katafuchi and colleagues, 2018; Lin and colleagues, 2025 |
| Very wide angle on a tissue-level implant | inflammation under a crown with a wide emergence | remake with a smaller angle, as depth allows | Raabe and colleagues, 2026 |
| No hygiene access | plaque and bleeding where the brush can’t reach | open embrasures and access in the design | Schwarz and colleagues, 2021 |
| Residual cement | bleeding or suppuration around a cemented crown with a deep margin | remove the cement; margin at the mucosal level or a screw-retained restoration | Staubli and colleagues, 2017 |
| Implant splinted to both neighbors | more disease at the middle implant | separate the units or open access between them | Yi and colleagues, 2020 |
| Short abutment | more marginal bone loss | abutment of 2 mm or more when depth allows | Lin and colleagues, 2025 |
Does changing the restoration help treat the disease?
Changing the contour helps as part of treatment, not instead of it. In the critical review by Mattheos and colleagues (Clinical Oral Implants Research, 2021), modifying the restoration contour was an effective adjunct to anti-infective treatment of peri-implant mucositis. The same review found that a sulcus of 3 mm or deeper reduces the effect of that treatment.
The restoration is one factor among several. In the review by Schwarz and colleagues (Journal of Clinical Periodontology, 2018), the strong evidence for risk lies in a history of periodontitis, poor plaque control and no regular maintenance. Submucosal cement, lack of keratinized mucosa and implant positions that hinder hygiene have limited evidence.
What should you put on the lab order?
For the lab to design a profile that favors the tissue, give the brand and platform, whether the implant is bone- or tissue-level, its depth below the mucosa and the profile you want. If a provisional has already shaped the tissue, scan its profile: it’s the reference the definitive crown will follow.
When the contour is critical, ask to see the design before milling: the case holds at the Approval stage and moves on only after you reply. Our article on screw- versus cement-retained implant crowns covers how to choose between the two. The provisional that shapes the tissue is on our milled PMMA provisionals page.
Who designs implant restorations at Smile Digital Lab?
Smile Digital Lab, a digital dental lab in São Paulo, Brazil, making restorations for oral rehabilitation, designs and mills implant crowns, provisionals and full-arch bridges with Neodent and Titaniumfix components, both made in Brazil. We check every case when it arrives and on eight points before it ships, and every stage is logged. The full range is on our implant restorations page; for full-arch bridges, the intaglio has its own guide on food trapping under a full-arch bridge.
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Open a portal accountFrequently asked questions
What emergence angle should I ask the lab for?
On bone-level implants, 30° or less with a straight or concave profile is what the studies linked to less peri-implantitis (Katafuchi, 2018; Lin, 2025). On tissue-level implants the reported threshold is wider, above 48° in Raabe (2026). Implant depth doesn't always allow it; the design shows that before milling.
Does a screw-retained crown prevent peri-implantitis?
In the systematic review by Lin and colleagues (2025), screw- and cement-retained restorations showed no difference in marginal bone loss. A screw-retained crown leaves no cement in the sulcus and comes off for maintenance; our article on screw- versus cement-retained implant crowns compares the two in detail.
Does splinting crowns on neighboring implants raise the risk?
In the data available, yes. In Yi and colleagues (2020), a middle implant splinted to both neighbors had more peri-implantitis, and in Lin's review (2025) non-splinted implants lost less bone. When splinting is needed, ask for embrasures an interdental brush can pass through.
Sources
- Restoration contour is a risk indicator for peri-implantitis: a cross-sectional radiographic analysis · Journal of Clinical Periodontology (Katafuchi et al., 2018)
- Association of prosthetic features and peri-implantitis: a cross-sectional study · Journal of Clinical Periodontology (Yi et al., 2020)
- Association of transmucosal emergence geometry and peri-implant diseases prevalence around bone- and tissue-level implants: a cross-sectional study · Clinical Oral Implants Research (Raabe et al., 2026)
- Implant-abutment emergence angle and profile in relation to peri-implantitis: a systematic review · Clinical and Experimental Dental Research (Soulami, Slot and van der Weijden, 2022)
- Peri-implantitis: summary and consensus statements of group 3. The 6th EAO Consensus Conference 2021 · Clinical Oral Implants Research (Schwarz et al., 2021)
- The influence of prosthetic designs on peri-implant bone loss: an AO/AAP systematic review and meta-analysis · Journal of Periodontology (Lin et al., 2025)
- Impact of design elements of the implant supracrestal complex (ISC) on the risk of peri-implant mucositis and peri-implantitis: a critical review · Clinical Oral Implants Research (Mattheos et al., 2021)
- Peri-implantitis · Journal of Clinical Periodontology (Schwarz, Derks, Monje and Wang, 2018)
- Excess cement and the risk of peri-implant disease - a systematic review · Clinical Oral Implants Research (Staubli et al., 2017)
- Diagnostic accuracy of peri-implant probing with or without prostheses in detecting peri-implantitis · Clinical Oral Implants Research (Xu et al., 2026)
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