The New 4mm (2.0 Version)

When 4 millimeters change everything: a day with no margin for error

“When bone disappears, responsibility doesn’t — it increases.”

Good morning, Chat. This week was incredible. We had the opportunity to be involved in the first human trial of the new 4-millimeter implant.

We were the second center to receive this implant — the first was in Austria, and the second was here.

It was a very well-spent day, where the team was extremely well-calibrated. We also had the opportunity to have Lea and her team sponsor a case. We performed two cases that day.

The first case was Mrs. Hermelinda, a full mandibular rehabilitation case.

She was missing almost all her teeth, with only three remaining. What we did was a plan in CoDiagnostiX for four implants between the mental foramina, BLC 3.75 by 10 mm, placed in a subcrestal position of approximately 3.5 millimeters. Then, to achieve an A- P (anterior-posterior) spread extending to the first molar region, we placed these 4-millimeter implants.

The patient had severe posterior atrophy, and these implants allowed the prosthesis to have posterior stability without a cantilever, with a good anteroposterior distribution so that the center of rotation remained centralized and did not overload the prosthetic components. ( see the related post)

We performed a crestal incision with full-thickness mucoperiosteal flap and two posterior releasing incisions, followed by full-thickness flap elevation to access both the left and right mental foramina. After exposure, we performed bone regularization using a round bur under irrigation.

I had prepared a pilot drill surgical guide supported by the remaining teeth — 36 and 37, as well as tooth 45, which had extreme mobility. The guide only provided a visual reference, as my main reference was the midline.

Mrs. Hermelinda had a mandibular fusion prominence that clearly marked the midline.

So some classic implant dentistry ( the so-called old-fashioned style)

Using a lance drill, I marked a central point parallel to the facial midline and positioned vestibulo-lingually toward the upper incisors, which defines the prosthetically driven implant center. Once this reference was established, I performed two osteotomies on the left and right for the lateral incisor positions.

This part was actually quite amusing, because I don’t particularly like the Straumann Velodrill system, so I prepared the osteotomies my own way: starting with a 2.2 mm drill, followed by a 2.8 mm cylindrical BLT drill, and then widening to 3.5 mm for a 3.75 by 10 implant. We placed the lateral incisor implants, then isolated the mental foramina and placed implants in positions 34 and 44 between the lateral implants and the foramina. Stability values were above ISQ 70, with one reaching 84. A predictable hit !!! If I were to use the 2.8 yellow velodril bye bye crestal bone......

The Main Character the Leading Actor: Ladies and gentlemen, the 4 mm ....

After this, we proceeded with the placement of the 4-millimeter implants. We had two distinct situations. One implant was placed in a post-extraction site after removing tooth 36, utilizing the triangular space between the mesial root and the mental foramen. We had only six millimeters available to place a 4 mm implant. The osteotomy required great care — and here is a key point: the entry into this triangle cannot be centered or purely mesial. It must begin as if entering the mesial root of the extracted tooth, allowing the drills and implant to engage correctly without losing the available space. This is a critical detail.

In the fourth quadrant, we had an easier scenario, as it was healed bone. Here, I initially made a mistake: I thought I had a 4.5 mm implant and prepared the osteotomy up to a 4.2 drill. When placing the implant, it had no stability. A panoramic radiograph clearly showed that the implant was “floating” and dangerously close to the inferior alveolar nerve. It was also not in a prosthetically correct position, with emergence around the 45 region. We decided to remove it and reposition more posteriorly. With the correct preparation, we achieved proper positioning and excellent stability.

We then entered a very interesting phase. After implant placement, I placed 4.5 SRAs on the anterior implants and healing abutments on the posterior implants, as they would not be loaded at this stage.

We followed a fully digital protocol. I used a simple template with two temporary cylinders, splinted together to establish the correct vertical dimension and sagittal maxillomandibular relationship. Once stabilized, I performed a complete scanning protocol: first the template, then the soft tissue and SRAs, followed by scan bodies connected with smart links. I also recorded the interocclusal relationship and sent everything to the lab, where Sofia fabricated a fully milled PMMA prosthesis.

We performed suturing with non-resorbable sutures and some resorbable Vicryl stitches, and placed healing caps. Three hours later, we delivered the provisional prosthesis and adjusted the occlusion.

It was an exceptional day. We had Benjamim and his filming team capturing everything. Maria Rita was highly focused, and Liliana and Arlete did an outstanding job. João Afonso came from Switzerland specifically to observe this case.

In the end, we all raised a glass to another case completed from A to Z, entirely in-house, using new implant technology.

A day to remember.