Same-Day Digital Dentistry Restorative Workflow for Single Immediate Provisionalization of Narrow-Diameter Implants: An Exploratory Prospective Study

Round 1

Reviewer 1 Report

This a well planed study and research project. The authors should be congratulated for it.

It's an easy to read manuscript that I think lacks on the number of patients but the inclusion requisites were understandable extensive.

I have some minor suggestions

Lines 157-159 need to be improved.

Line 189 at the visit of digital scanning and insertion of 190 the definitive abutments and crowns please shorten this it's too confusing

Line 217, 218, 222 and others are  missing +/- and commas

Lines 225-228 are unreadable and should be a table. I dislike so much detail that's easier read on a table. I prefer that the text highlights the main results found in table x (but it's a personal preference)

Tables are too big/wide and need formatting 

On a personal note I chose no to prep the titanium abutments in the mouth due to the risk of titanium particles being trapped in the gums causing long term inflammation.

I will be waiting for your future results. 

Author Response

RESPONSES TO REVIEWER #1

This a well planned study and research project. The authors should be congratulated for it.

It's an easy to read manuscript that I think lacks on the number of patients but the inclusion requisites were understandable extensive.

I have some minor suggestions

Lines 157-159 need to be improved.

RESPONSE: We appreciated the comment on the lines below:

“… The unsintered milled crown was then tried in. The crown surface was characterized and adjusted to mimic the adjacent and contralateral tooth surface morphology, texture, and characterization. The crown was then characterized and sintered. The implant screw access hole was then filled with a piece of Teflon tape…”

TEXT CHANGE: We revised the text to:

“After the milling finished the unsintered crown was inserted to determine the proximal fit and to customize the crown surface mimic the adjacent and contralateral tooth surface morphology, texture, and characterization. The crown was then stained with feldspathic ceramics and sintered. The implant screw access hole was then filled with a Teflon tape barrier.”

Line 189 at the visit of digital scanning and insertion of 190 the definitive abutments and crowns please shorten this it's too confusing

RESPONSE: Thank you for pointing this out. The original sentence below is now revised.

“Standardized periapical radiographs were taken with the patient’s occlusal registration at the implant placement visit, at the visit of digital scanning and insertion of the definitive abutments and crowns, and then at one-year and two-year follow-up visits.”

TEXT CHANGE: We revised the text to”

“Standardized periapical radiographs were taken at the implant placement visit, at the visit of digital scanning and prosthesis fabrication, and then at one-year and two-year follow-up visits.”

Line 217, 218, 222 and others are  missing +/- and commas

RESPONSE: We appreciate the comment.

TEXT CHANGE: The revised text is now read:

“The average age of the patients at the time of implant placement was 47.5 ±18.0 years. No implant failure was reported. Thus, the implant survival rate was 100%. It took on average 127.4 ±53.0 days from the implant surgery to the day of definitive crown fabrication and insertion. The most common implant length used was 11.5 mm, which accounted for over half of the implants used (6 out of 11). Two implants were placed immediately after extractions. The ISQ values were 73.50 ±12.01 at the time of the placement, and 76.59 ±11.87 at the time of prosthetic insertion.

Lines 225-228 are unreadable and should be a table. I dislike so much detail that's easier read on a table.

I prefer that the text highlights the main results found in table x (but it's a personal preference)

RESPONSE: Thank you for pointing this out. The information is now in a table form (Table 4)

TEXT CHANGE: See Table 4 and revised text below:

“Two implants were placed immediately after extractions. The ISQ values were 73.50 ±12.01 at the time of the placement and 76.59 ±11.87 at the time of prosthetic insertion. The mesial and distal crestal bone loss values were -0.56 ±0.54 mm and -0.32 ±0.68 mm. Negative values signified bone resorption. The probing depth changes were shown in Table 3.  Implant mobility was not found at any time point.  The gingival inflammatory (GI) scores, bleeding on probing (BOP) scores, the modified gingival index (MGI) scores, and the plaque index (PI) scores were shown in Table 4.”

Table 4 Clinical evaluation measures

*measures used only after the prosthetic insertion

RESPONSE:

TEXT CHANGE:

Tables are too big/wide and need formatting

RESPONSE: We appreciate the comment.

TEXT CHANGE: Tables are now reformatted to fit the text.

On a personal note I chose no to prep the titanium abutments in the mouth due to the risk of titanium particles being trapped in the gums causing long term inflammation.

RESPONSE: We appreciate the comment. However, the clinical protocol was set prior to the study.

TEXT CHANGE: N/A

I will be waiting for your future results.

RESPONSE: Appreciate your kind insight and thorough review very much.

TEXT CHANGE: N/A

Reviewer 2 Report

Dear Authors, first of all I would like to congratulate You on your work. The topic Is of great clinical relevance. The reviewer really appreciates the efforts of the authors to conduct this study which has a good clinical significance. However, there are lots of scopes to improve the quality of the manuscript. The reviewer would like to suggest the following revision in the manuscript to make it suitable for publication.

Abstract: is precisely written, and the aim of the study is mentioned. Please include some more information about the results/finding to enhance the impact of this section.

The introduction; is detailed, compact, covering the background information and the rationale of the study effectively. However, the last paragraph is very details and suggested to condense that information.

Discussion- this paragraph should be rearranged. It is very chaotic. Please do not repeat information from Introduction and try to be more focused. Rewrite this section using following paragraphs: main results and clinical relevance; comparison with other studies; advantages and disadvantages of the study; conclusions and suggestions for future studies.

Furthermore, In discussion, more studies in context should be included; as there is little support of literature from the previous studies. I would suggest this paper to increase your article: 

"Dental restorative digital workflow: Digital smile design from aesthetic to function"

The conclusion section needs to be revised with a more clear and summarized outcome of the paper.

I believe that your manuscript would have much more relevance after suggested improvements.

Author Response

REVIEWER #2

Dear Authors, first of all I would like to congratulate You on your work. The topic Is of great clinical relevance. The reviewer really appreciates the efforts of the authors to conduct this study which has a good clinical significance. However, there are lots of scopes to improve the quality of the manuscript. The reviewer would like to suggest the following revision in the manuscript to make it suitable for publication.

Abstract: is precisely written, and the aim of the study is mentioned. Please include some more information about the results/finding to enhance the impact of this section.

RESPONSE: Appreciate the kind comment. We had a 200-word limit per the journal format.

TEXT CHANGE: However, we highlighted a few results and revised the abstract as follow:

“This study evaluated a 2-year clinical outcomes of  3.1-mm-diameter dental implants immediately provisionalized and later restored using same-day dentistry in 10 patients receiving 11 narrow-diameter (3.1 mm) single implants. Each implant was placed and immediately restored with a provisional crown after the placement. At least 2 months after the placement, the implant was restored with a prefabricated titanium abutment and an all-ceramic crown using same-day dentistry protocol. Clinical outcomes including apical bone loss, probing depths, and gingival index, surgical and prosthetic complications were documented. There was no implant failure over the course of two years. No surgical complications were reported. Two cases lost provisional crowns. One crown needed to be remade due to esthetic concern. The cumulative two-year survival rate of the implants was 100%. Implant bone loss after a two-year of functional loading were -0.56 ±0.54 mm and -0.32 ±0.68 mm for mesial and distal crestal bone. Two prosthetic complications included recementation of a crown and remaking of a crown. This exploratory study suggests that immediate provisionalization and a same-day restorative dentistry digital workflow protocol for narrow-diameter implants appear to be predictable clinical procedures with no reported surgical complications and minimal prosthetic complications.”

The introduction; is detailed, compact, covering the background information and the rationale of the study effectively. However, the last paragraph is very details and suggested to condense that information.

RESPONSE: Thank you for the kind comment.

TEXT CHANGE: The paragraph is shortened and summarized as follow:

“Recent advances in digital dentistry allow same-day CAD-CAM dentistry to become a routine practice.[17,18] For NDIs, in general, the digital and prosthetic options are often limited due to the size of the implants. There is little information on the fabrication of NDI implant crowns using a same-day digital dentistry protocol. This prospective exploratory study, therefore, aimed to evaluate clinical outcomes when single NDIs were immediately provisionalized and later restored using a same-day dentistry restorative workflow.”

Discussion- this paragraph should be rearranged. It is very chaotic. Please do not repeat information from Introduction and try to be more focused. Rewrite this section using following paragraphs: main results and clinical relevance; comparison with other studies; advantages and disadvantages of the study; conclusions and suggestions for future studies.

RESPONSE: We truly appreciate the comments.

TEXT CHANGE: The Discussion is now read as follow:

The main results of this exploratory study present the success of immediate provisionalization of single NDIs together with a same-day dentistry prosthetic fabrication protocol. This treatment protocol of immediate provisionalization of NDIs has demonstrated a high implant success rate of 100%. This option allows clinicians to use titanium prefabricated abutments instead of Ti-base abutments that are often not available for NDIs. [16,19]

Comparing to other studies, this protocol demonstrated comparable results with minimal mesial-distal peri-implant bone loss of ~0.3 to 0.6 mm after two years of implant placement. These bone remodeling value are similar to ~0.35 mm bone resorption on average from a study reporting on immediate provisionalization of NDIs after one year following implant placement,[16] and from a study with delayed provisionalized protocol.[20] Immediate or delayed provisionalization appeared to have no effect on bone loss.[16,20] The long-term bone loss of <0.2 mm per year after the first year has been reported for NDIs.[21]  While the peri-implant bone and gingival health along with implant success results of the current study were almost identical with previously reported outcomes by Oyama et al,[16] the prosthetic complications were different. Only two crowns in this study required recementation or remake, accounting for 18% minor prosthetic complications with no complications observed during the provisional stage. On the other hand, in Oyama et al study,[16] more prosthetic complications at the provisional crown stage were reported, including seven fractured provisionals, two debonded provisionals, three loosened provisional abutment screws, all within the first three months following implant surgery, accounting for 70% for prosthetic complications. This may infer the different implant design and provisional-abutment and implant connection, as well as the difference between using titanium prefabricated provisional abutments with bisacryl resin in this study and the use of titanium-base polyetheretherketone (PEEK) abutments with flowable composite resin in Oyama et al.[16]

There are multiple factors in the preservation of crestal peri-implant bone. Immediate provisionalization of conventional dental implants and NDIs has been shown to preserve crestal peri-implant bone and prevent the first year of peri-implant bone resorption.[20,22] Other factors, however, such as the implant fixture platform switching design,[23] the microthread cervical design,[24] the stability of the implant-abutment friction-fit design, and reduction of micromovement/microgap,[24,25] may also have a favorable effect on the reduction of the crestal peri-implant bone resorption. Note here that in this study protocol, flap surgery was employed except for the immediate placement implants. It is possible that the bone resorption may have been reduced further if flapless surgery were used.[26–29]

Advances in digital technology including intraoral scanning, CAD-CAM prosthetic design, and milling of the definitive implant restoration allow for the same-day implant crown fabrication.[17,18,30,31] The majority of same-day implant crown fabrications rely however on the availability of titanium-based (Ti-base) prefabricated abutments together with a ceramic block with pre-milled implant screw-access.[17,18] This option is often missing for NDIs. Therefore, in this study, a prefabricated titanium implant abutment was used with monolithic lithium disilicate crown fabricated using CAD-CAM technology. One of the issues identified during this pilot clinical trial was the grayness of titanium abutment showing through at the facial cervical gingiva and in one case, the crown needed to be replaced after additional preparation at the facial margin to drop the crown margin slightly deeper subgingivally. Titanium abutment preparation is therefore an important issue to ensure optimization of the scanning ability as well as the milling capacity of the restoration.[17,32] The same-day dentistry protocol for NDIs appears otherwise to be very successful and in most cases, the patients were pleased with the treatment outcome esthetically and with the speed of the treatment. The monolithic lithium disilicate crown was prescribed in this study to allow the same-day dentistry protocol without compromising the esthetics of the restorations since zirconia restoration would have taken longer and likely would not be done in the same day.[18]

It is also important to note here that after enrolling and performing implant placement for the first seven patients, our clinic facility had to close for three months due to the COVID-19 pandemic. Some of our short-term care such as surgical recalls and restorative work had to be delayed. Some of the patients also refused to come back for the clinical follow-up until after the peak of the pandemic. While the COVID-19 pandemic has undoubtedly some adverse effects on the clinical protocol, same-day crown fabrication reduces treatment visits which eases the patient’s anxiety about seeing a dentist during the pandemic. Several previous studies demonstrated that patients prefer digital impressions over conventional elastomeric impression for a single implant.[33–37] Digital workflow for a single implant restoration has shown to be more effective and less expensive, with shortened treatment time and reduced number of clinical visit.[37–40]

It is important to discuss some limitations of this pilot study and possible future clinical studies. First, the sample size of this study was limited. The sample size of ten was planned for this study as a pilot exploratory clinical trial to provide the baseline data for future larger clinical studies. In the future, there is a potential for a clinical trial for immediate fabrication and insertion of the definitive crown together with guided implant surgery and CAD-CAM same-day dentistry. Second, only the titanium prefabricated abutments were used here. Other types of abutments such as zirconia fused titanium base may give different or even a better esthetic outcome. Third, in this study, while digital implant planning was employed, guided implant surgery was not applied. In the future, guided implant surgery can be applied together with possibly a definitive restoration fabricated ahead of the surgery. More importantly, nowadays digital smile design can be an important part of routine treatment planning.[41]  A future studies to incorporate fully digital smile design and guided implant surgery will be important to provide insight into the contemporary practices. Finally, the periapical radiograph is limited to 2D data and the superimposition of facial and lingual bones can potentially alter the results.

Furthermore, In discussion, more studies in context should be included; as there is little support of literature from the previous studies. I would suggest this paper to increase your article:

"Dental restorative digital workflow: Digital smile design from aesthetic to function"

RESPONSE: Thank you for pointing out this important reference.

TEXT CHANGE: We add this information and add this reference (as Reference #41) in the last part of the Discussion on future studies (See above comment/response).

Reference #41

Cervino G, Fiorillo L, Arzukanyan AV, Spagnuolo G, Cicciù M. Dental Restorative Digital Workflow: Digital Smile Design from Aesthetic to Function. Dent J (Basel). 2019, 7, 30.

The conclusion section needs to be revised with a more clear and summarized outcome of the paper.

I believe that your manuscript would have much more relevance after suggested improvements.

RESPONSE: Thank you for this insight.

TEXT CHANGE: New conclusion is now read as follow:

“NDIs are a viable alternative treatment for anterior and premolar implant sites without additional grafting or generative surgery. This exploratory study demonstrated that not only NDIs can be immediate provisionalized after implant placement in esthetic zone, but the study also highlights the fact the titanium preparable prefabricate abutments can be used together with same-day dentistry protocol with 100% implant survival rate over 24 months and minimal peri-implant bone loss or complications.”

Author Response File: Author Response.docx